751.22 P/S Concrete I Girders

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Concrete Girder

Contents

751.22.1 General

751.22.1.1 Material Properties

Concrete

Concrete strength utilized for prestressed girders may be conventional or high strength concrete (HSC) which shall be identified on the girder plans. HSC shall be concrete strengths in excess of 8.0 ksi and may only be used with the permission of the Structural Project Manager or Structural Liaison Engineer. Costs may increase due to production modifications necessary to obtain the required HSC strength.

Conventional concrete strength for P/S I-Girder shall be the following:

For MoDOT Standard Girders:
\, f'_{ci} = 4.5 ksi, \, f'_c = 6.0 ksi
Optional higher concrete strength shall be:
\, f'_{ci} = 5.0 ksi, \, f'_c = 7.0 ksi
OR
With the approval of the Structural Project Manager or Liaison:
\,f'_{ci} = 6.5 ksi, \,f'_c = 8.0 ksi
For NU Standard Girder:
\,f'_{ci} = 6.5 ksi, \,f'_c = 8.0 ksi


Modulus of Elasticity, \, E_c = 33,000\ K_1 \ (w_c^{1.5}) \sqrt{f^'_c}
Where,
f'c in ksi
K1 = correction factor for source of aggregate
= 1.0 unless determined by physical testing
w_c = 0.145 kcf\ \mbox{for}\ f'_c\le 5.0 ksi
w_c = 0.140 + 0.001 f'_c\ \mbox{for}\ f'_c>5.0 ksi
 
Prestressing strand
Type of strand:
AASHTO M203 (ASTM A416) Grade 270
Uncoated, seven-wire, low-relaxation strand
Ultimate tensile strength, \,f_{pu} = 270 ksi
Yield strength, \,f_{py} = 0.9 f_{pu} ksi
Strand modulus of elasticity, \,E_p = 28500 ksi
For conventional concrete strengths:
  Strand diameter, \,d_{ps} = 0.5 in
  Strand area, \,A_{ps} = 0.153 in^2
OR:
  Strand diameter, \,d_{ps} = 0.6 in
  Strand area, \,A_{ps} = 0.217 in^2
Maximum allowed initial prestress force (immediately prior to transfer)

= fpbt = 0.75fpu kips      LRFD table 5.9.3-1

Maximum allowed initial prestress force per strand

= Aps x fpbt kips

Maximum allowed initial force = 30.98 kips for 0.5 inch diameter strand

                                                   43.94 kips for 0.6 inch diameter strand

Total initial prestress force = (# of strands) x (required* initial prestress force per strand)
* Typically the required prestress force per strand is the maximum allowed prestress force.
Note: Report on the girder plans the required number of strands by design and the total initial prestress force using EPG 751.50 Standard Detailing Notes H2c1.3.  
Order of Material Use for Increasing Girder Capacity in Order of Increasing Costs
1. Increase concrete strength (readily producible by fabricator)
2. Increase strand size (readily available from fabricator but steel costs are high)
3. Modify MoDOT shape (most costly and inconvenient because of forming bed modifications required) (except NU shape)
 
Mild reinforcing steel
Minimum yield strength, \,f_y = 60.0 ksi
Steel modulus of elasticity, \,E_s = 29000 ksi
 
Welded Wire Reinforcement
Minimum yield strength, \,f_y = 70.0 ksi
Steel modulus of elasticity, \,E_s = 29000 ksi

751.22.1.2 Geometric Dimensions

The ratio of the depth of girder to span length will in general be not less than 1/18.

The cross sectional dimensions of the girder shall be one of the following:

MoDOT Standard Girders:
Image:751.22_dim_beam_types_2_thru_6.gif
BEAM TYPE 2 BEAM TYPE 3 BEAM TYPE 4 BEAM TYPE 6


Image:751.22_dim_beam_types_7_8.gif


BEAM TYPE 7 BEAM TYPE 8


* If the web is required to be increased, then the top and bottom flanges are to be increased by the same amount. (1" increments 2" max.).


NU Standard Girders:
BEAM NU 35 A = 639.79 in.2 Yb = 15.96 in. Yt = 19.48 in. Ixx = 108,498 in.4 Iyy = 60,086 in.4 V/S = 3.067 in.
BEAM NU 35
A = 639.79 in.2
Yb = 15.96 in.
Yt = 19.48 in.
Ixx = 108,498 in.4
Iyy = 60,086 in.4
V/S = 3.067 in.


BEAM NU 43BEAM NU 53
A = 686.05 in.2A = 743.88 in.2
Yb = 19.36 in. Yb = 23.71 in.
Yt = 23.95 in.Yt = 29.44 in.
Ixx = 179,343 in.4Ixx = 297,512 in.4
Iyy = 60,219 in.4Iyy = 60,385 in.4
V/S = 3.058 in.V/S = 3.048 in.


BEAM NU 63BEAM NU 70
A = 801.72 in.2A = 847.98 in.2
Yb = 28.14 in. Yb = 31.74 in.
Yt = 34.86 in.Yt = 39.14 in.
Ixx = 451,306 in.4Ixx = 601,931 in.4
Iyy = 60,551 in.4Iyy = 60,684 in.4
V/S = 3.040 in.V/S = 3.034 in.

751.22.1.3 Typical Span Ranges

The following charts provide span ranges (limits) for P/S I-girders based on girder spacing and standard roadway widths.

Limitations of the Charts:

A. Standard Concrete Charts Only
Criteria used in determining maximum span lengths for lower conventional concrete strength:
1) Low-relaxation strand with 0.5” strand diameter
2) Concrete strengths, \, f'_{ci} = 4.5 ksi and \, f'_c = 6.0 ksi
3) 3-span bridge consisting of 3 equal length girders made continuous and composite
B. Optional Concrete Charts Only
Criteria used in determining maximum span lengths for greater conventional concrete strength:
1) Low-relaxation strand with 0.6” strand diameter
2) Concrete strengths, \, f'_{ci} = 5.0 ksi and \, f'_c = 7.0 ksi
3) 3-span bridge consisting of 3 equal length girders made continuous and composite
C. Both Standard Concrete and Optional Concrete Charts
Criteria used in determining span ranges for both Standard and Optional Concrete conventional strengths.
1) Minimum span lengths were determined by the positive moment capacity of the smallest strand arrangement per beam shape. Shorter span lengths are possible.
2) Based on 10 ft. design lanes. (Current design practice meets AASHTO LRFD and uses 12 ft. design lanes.)
3) Based on unrefined prestress loss equations. (Current design practice meets AASHTO LRFD and uses refined losses.)

Recommended Adjustments for Using the Charts:

Because the span limit charts were developed using older design criteria as noted above, increased span lengths are probable.

1) Span limits given in all charts should be increased 10 percent to account for current design practice. Ten percent can safely be used without a preliminary girder analysis.
2) Span limits given in all charts shall be increased when a preliminary girder analysis based on actual design conditions is performed which shall be noted on the Design Layout.


Span range charts are planned for future replacement. Use the recommended adjustments until implemented.


Standard Concrete (\, f'_c = 6 ksi) P/S I Beam Span Ranges for
Given Roadway Widths and Girder Spacing
Image:751.22_standard_conc_PSI_span_ranges.gif


Optional Concrete (\, f'_c = 7 ksi) P/S I Beam Span Ranges for
Given Roadway Widths and Girder Spacing
Image:751.22_optional_conc_PSI_span_ranges.gif

751.22.1.4 Span and Structure Lengths

Girder Length and Geometric Layout

Tangent Bridges
Girder lengths of exterior spans (i.e., end spans) shall be computed using the requirements shown below.
Girder lengths of interior spans shall be computed using the requirements shown below.
Curved Bridges
Layout of any curved structure may be done using any coordinate geometry programs available. To layout the bridge, use the following steps:
  1. Start out by laying in the centerline (CL) of the survey curve.
  2. Locate the tie point of the bridge. This point will usually be on the CL of the survey curve but may be on a baseline which is offset a certain distance to the CL of the survey curve.
  3. A second tie point may be required if the skew is not measured to the CL of roadway at the bridge tie point. If this is the case, establish the tie point at the specified station and plot the skew line at the required angle.
  4. Next, on the centerline of structure or baseline curve, locate the station of the CL of bent for each intermediate bent and the fill face for the end bents. Once these points are located, plot lines through these stations parallel to skew line. Normally the layout file will specify that all bents are parallel to the skew line; however, there may be times when the bents are radial or have varying skews.
  5. When locating the stations in the preceding step, the distance between CL of intermediate bents are exactly the layout lengths specified on the file. However, the end spans need to follow the procedure for calculating length set forth in this section.
  6. When the CL of the intermediate bents and the fill face lines have been added, chords should be drawn connecting these points sequentially. For example, if you have a three span bridge, chords should be drawn from the fill face of bent 1 to CL of bent 2, CL bent 2 to CL bent 3, and CL bent 3 to fill face bent 4.
  7. When all the chords are in, offset each girder in each span parallel to this chord. The perpendicular distance between girders will be the same for all spans, but the skew distance between girders along the bent will vary from bent to bent depending on the skew to the CL at that point. The designer needs to be aware of the fact that at an intermediate bent the distance between bearings on the approaching and leaving span sides will be different distances. These bearings will not line up across the bent and will actually diverge more the farther away they are from the CL of the survey.
  8. When establishing the CL of bearing points, the designer needs to allow for a minimum of seven (7) inches between ends of girders at the bents while keeping in mind that the girders will be offset and at different skews. If the offset is greater than half the girder bottom flange width, see Structural Project Manager. The distance from the end of girder to CL of bearing point should be half of the bearing length plus one inch minimum clearance. Once the distance for CL bent to CL of bearing is calculated, the designer should offset lines by that dimension on either side of the CL of bent. These lines will then be intersected with each of the girder lines to create the bearing points on each bent.
  9. Between the bearing points at the ends of the girders, quarter points or tenth points need to be established, depending on the girder span. These points will be used in calculating the haunch and bottom of slab elevations for the bridge deck.
  10. The bridge deck and barrier curbs can be laid in by offsetting the CL of roadway to each side by the proper distance. Curves should be laid in to designate both the inside and outside edges of the barrier curb. These will later be useful in laying in the wings and end bents.
  11. After the outside edge of slab curves are plotted, the curve offsets need to be found. The intersection point of the outside edge of slab and the CL of each bent or fill face can be connected with chords. The distance between these chords and their partner curves need to be calculated at five foot intervals beginning at the center point of each chord.
  12. Joints are placed in the barrier curb at each bent. These joints are placed perpendicular to the CL of the roadway through the intersection point of the CL bent and the inside of barrier curb.
  13. Wing layout length is given on the profile sheets in the layout file. An arc should be struck so as to intersect the inside of barrier curb the specified length from a point at the intersection of the fill face and the inside of barrier curb. This point will mark the end of the wing which is perpendicular to the CL of the roadway.
The vertical curve information needs to be added so a program can calculate the elevations at the desired stations. After this is done, the designer can request any of the following information which will be needed:
  • Stations and elevations of all points
  • Offset distances to the chords
  • Lengths of girders
  • Distances between bearings
  • Angles between girders and each bent
  • Lengths of bents
  • Lengths of barrier curbs between joints
  • Minimum vertical clearance


INTEGRAL END BENTS


NON-INTEGRAL END BENTS


Note: Layout length for single span shall be measured from centerline of bearing to centerline of bearing. If the difference between layout length of the end span and interior span is within 1 ft., then layout length should be adjusted if possible so the girder lengths are equal for end span and interior span.
(*) Minimum dimension from edge of bearing pad to end of girder equals one inch.
(**) Design layout lengths are horizontal lengths. Girder lengths should be adjusted according to grade and shall be specified to the nearest 1/8 inch.
(***) For large skews, end bent beam caps may need to be larger to provide edge distance.
(****) Horizontal distance along certerline of girder.
(*****) = 1” (minimum) + ½ bearing pad length which equals:
5” (minimum) for MoDOT Standard Girders and Adjacent P/S Box Beams,
3 ½” (minimum) for NU Girders and P/S Spread Box Beams.


PART PLAN SHOWING COPING DETAIL
(MoDOT Standard Girders and NU Girders)

Note: Non-Integral end bents with skews greater than 40° shall always have girder ends coped. Skews less than 40° shall have girder ends coped on case by case basis. It is preferable to not cope across the web.

Check clearance from fill face of integral end bents to bottom flanges of NU standard girders. Maintain 3” (min.) clearance. Coping may be permitted with approval of the Structural Project Manager or Structural Liaison Engineer.

(*) Maximum length from End Bent to End Bent = 600 feet.
TYPICAL CONTINUOUS PRESTRESSED STRUCTURE
(INTEGRAL END BENTS)


Image:751.22_typ_continuous_PS_structure_Non_Integral_End_Bents.gif
(**) Maximum length from End Bent to End Bent = 800 feet.
TYPICAL CONTINUOUS PRESTRESSED STRUCTURE
(NON-INTEGRAL END BENTS)

751.22.1.5 Constant and Varied Joint Filler Loads

Varied joint filler load

The prestressed I-girder should first be designed assuming that the contractor will vary the joint filler supporting the panels on the girder flange. This assumption will maintain the minimum slab/panel combination thickness of 8 1/2”, and will eliminate the possibility of increased load due to varying slab thickness.


Constant joint filler load

With the girder designed and the camber and haunching dimensions calculated, the girder should be checked assuming the contractor will use a constant 1” joint filler. This will cause the slab thickness to vary due to camber of the girder, increasing load. This additional load shall be placed as a concentrated load at 1/8 point from each end of the girder.

An example of how this concentrated load could be calculated is shown as follows:

Load \, w = (A)(0.15 kips/ft.^3)
Determine the concentrated load* to girders by distributing w transversely across the girders. If the minimum haunch is greater than 1” joint filler, the additional haunch shall be included in the slab thickness as a uniform load. If the use of these loads causes the girder design to change, it shall be the responsibility of the designer to determine if the camber and haunching should be recalculated.

* This load shall be positioned at the 1/8 point from centerline of bearing pad.

The girder and bearing designs should be checked for the constant joint filler option and constant joint filler load. However, camber, haunching and beam seat elevations shown on the plans should be based on the variable joint filler option.


Image:751.22_Joint_Filler_Loads.gif
JOINT FILLER LOADS

751.22.2 Design

751.22.2.1 Load Combinations

In general, each component shall satisfy the following equation:

\,Q = \textstyle \sum\,  \eta_i  \gamma_i  Q_i  \le  \phi  R_n = R_r


Where:

\,Q= Total factored force effect
\,Q_i= Force effect
\,\eta_i= Load modifier
\,\gamma_i= Load factor
\,\phi= Resistance factor
\,R_n= Nominal resistance
\,R_r= Factored resistance


Limit States

The following limit states shall be considered for P/S Girder design:

SERVICE I - for compressive stress
SERVICE III - for tensile stress
STRENGTH I

See LRFD Table 3.4.1-1 for Loads and Load Factors applied at each given limit state.


Resistance factors, \,\phi

STRENGTH limit states, see LRFD Article 6.5.4.2 & 5.5.4.2.1
For all other limit states, \,\phi = 1.00


See EPG 751.2.3.1 Load Modifiers.

751.22.2.2 Prestressing Strands

Transfer Length of Prestressing Strands

The prestressing force may be assumed to vary linearly from zero at the point where bonding commences to a maximum at the transfer length. The transfer length may be taken as 60 times the strand diameter.


Development Length of Prestressing Strands

The development length for prestressing strands shall be taken as:

\,l_d\ge1.6\Bigg(f_{ps}-\frac{2}{3}f_{pe}\Bigg)d_{ps}

Where: \,d_{ps} = Nominal diameter of strand, (in.) \,f_{ps} = Average stress in prestressing strand at the time for which the nominal resistance of the girder is required, (ksi)


Stress limits for prestressing strands

Strand stress at service limit state shall not exceed the following:

At jacking:

\,f_{pj}\le0.75f_{pu} ksi
(For typical girders and fabrication economy, \,f_{pj} = 0.75 f_{pu})

At service limit state after all losses:

\,f_{pe}\le0.80f_{py} ksi

Where:

\,f_{pj} = Stress in prestressing strand at jacking, (ksi)
\,f_{pe} = Effective stress of strand after all losses, (ksi)
\,f_{py} = Yield strength of strand, (ksi)
\,f_{pu} = Ultimate tensile strength of strand, (ksi)


Prestress Losses

Refined estimates of time-dependent losses are used, based on AASHTO LRFD Article 5.9.5.4, as opposed to approximate lump sum estimate of losses in AASHTO LRFD Article 5.9.5.3.

The prestress losses shall be calculated to investigate concrete stresses at two different stages.

  1. Temporary stresses immediately after transfer:
  2. Final stresses


SERVICE I and SERVICE III Limit states shall be investigated at each stage.

Harped Strands

Harped strands, although they add to the shear strength of the girder, are primarily used to keep the girder stresses (both top and bottom) within allowable limits while developing the full capacity of the girder at midspan.

Harped strands should be held down at points of 0.4 of the distance from each end of the girder. Distances along girder to hold-down devices and between hold-down devices should be reported on the plans to the nearest inch. Per Sec 1029, precaster may position hold-down devices +/- 6 in. longitudinally from position shown on the plans.

Image:751.22_harped_strand_layout.gif


Example Harped Strand Layout


The jacking force applied to prestress strands produces an excessive vertical uplift in short spans on tall girders resulting in failure of harped strand hold-downs. The allowable limits for hold-downs are as follows:

  1. 5 kip/strand
  2. 10 kip/bolt
  3. 42 kip/hold-down


Image:751.22_hold-down_device.gif


Hold-Down Device


If necessary lower harped strand end location to meet criteria or use straight strands only. Investigate the possibility of using all straight strands when strength check of a hold-down device exceeds allowable.

Straight Strands.

Short spans (<40 ft.) are to use straight strands only for all girders greater than 2'-8" tall. Use at least two straight strands at the top of the girder when straight strands are used. Where straight strands only will not work a single hold-down point may be used. Note: A single point hold-down has twice the uplift force.

Strand Arrangement Optimizing

Using all straight strands for girder lengths less than 70 ft. should be investigated for MoDOT Standard Girder Types 6, 7, 8 and all NU Standard Girders in order to reduce risk of strand or hold-down breakage, increase safety by reducing risk of injury during fabrication and reduce cost.

Consider using the same section for all spans. This permits the use of shorter girders in the casting bed with longer girders, even if straight strands are needed, in the top flanges of the girders. They can be placed at either end of the bed and still optimize the usage of the bed.

Consider using the same number of draped strands for all spans and debond where needed. Strand patterns should be similar between long and short spans. For example, the designer should not use a single column of draped strands on the short spans and two columns of draped strands on the long spans. This will prevent optimization of the bed.

When using straight strands in the top flange of NU Girders and harped strands, lower (drop) the harped strand end locations and vertically align straight strands directly over harped strands to facilitate top flange blockout fabrication by removing interference created between straight strands placed to the outside of the harped strands and the flange blockout forms. If for any reason this is not possible, then place straight strands to the outside of the harped strands.

Debonding Strands

In all debonding operations the prestressing forces must be in such a manner as to prevent any sudden or shock loading.

Debonding a strand consists of wrapping the unnecessary strand(s) with a polyethylene plastic sleeve that prevents interaction of the strand with the concrete during casting and release which prevents any prestress force transfer.

751.22.2.3 Flexure

Flexure capacity of prestressed I-girders shall be determined as the following.

Flexural resistance at strength limit state

\,M_r = \phi M_n \ge M_u

Where:

\,M_r=Flexural resistance
\,M_n=Nominal flexural resistance
\,M_u=Total factored moment from Strength I load combination
\, \phi = Flexural resistance factor as calculated in LRFD 5.5.4.2


Negative moment reinforcement design

P/S I-girder shall be designed as a reinforced concrete section at regions of negative flexures (i.e., negative moments).

At least one-third of the total tensile reinforcement provided for negative moment at the support shall have an embedment length beyond the point of inflection not less than the specified development length of the bars used.

Slab longitudinal reinforcement that contributes to making the precast beam continuous over an intermediate bent shall be anchored in regions of the slab that can be shown to be crack-free at strength limit states. This reinforcement anchorage shall be staggered. Regular longitudinal slab reinforcement may be utilized as part of the total longitudinal reinforcement required.


Effective Slab Thickness

An effective slab thickness shall be used for design by deducting from the actual slab thickness a 1” integral, sacrificial wearing surface.


Design A1 reinforcement in the top flange

The A1 reinforcement shall resist the tensile force in a cracked section computed on the basis of an uncracked section.

For MoDOT Standard Girders, A1 reinforcement shall consist of deformed bars (minimum #5 for Girder Type 2, 3 and 4 and minimum #6 for Girder Type 6, 7 and 8).

For NU Standard Girders, A1 reinforcement shall consist of the four 3/8-inch diameter reinforcement support strands with deformed bars added only as needed. The WWR in the top flange shall not be used for A1 reinforcement because there is insufficient clearance to splice the WWR.

Reinforcement shall be designed and spliced using f’ci in accordance with EPG 751.5.9.2.7 Development and Lap Splices.


Required steel area is equal to:


\,A1=\frac{T_t}{f_s}


Where:

\, f_s= \, 0.5 f_y \le 30 KSI, allowable tensile stress of mild steel, (ksi)
Tt= Resultant of total tensile force computed on the basis of an uncracked section, (kips)


Limits for reinforcement

The following criteria shall be considered only at composite stage.

Minimum amount of prestressed and non-prestressed tensile reinforcement shall be so that the factored flexural resistance, Mr, is at least equal to the lesser of:

1) Mcr       LRFD Eq. 5.7.3.3.2-1
2) 1.33Mu

Where:

Mcr=Cracking moment, (kip-in.)
Mu =Total factored moment from Strength I load combination, (kip-in.)

751.22.2.4 Shear

Shear capacity of P/S I-girder should be checked along girder length and girder-slab interface.


Shear resistance at strength limit state

\, V_r = \phi V_n \ge V_u

Where:

\, V_r=Shear resistance
\, V_n=Nominal shear resistance
\, V_u=Total factored shear from Strength I load combination
\, \phi=Shear resistance factor


Nominal shear resistance

The nominal shear resistance, \, V_n, shall be lesser of:

  • \, V_c + V_s + V_p, or
  • \, 0.25 f'_{c} b_v d_v + V_p


Where:

\, V_c = 0.0316 \beta b_v d_v \sqrt{f'_c}


\, V_s = \frac {A_v f_y d_v (cot \theta + cot \alpha) sin \alpha}{s}


Where:

\, V_c=Nominal concrete shear resistance, (kips)
\, V_s=Nominal shear reinforcement resistance, (kips)
\, V_p=Component of prestressing force in the direction of shear force, (kips)
\, b_v=Thickness of web, (in.)
\, d_v = Effective shear depth taken as the distance measured perpendicular to the neutral axis, between the resultants of tensile and compressive forces due to flexure, (in.)
\, s=Spacing of shear reinforcement, (in.)
\, \beta=Factor indicating ability of diagonally cracked concrete to transmit tension
\, \theta=Angle of inclination of diagonal compressive stress, (degree)
\, \alpha=90.0, Angle of inclination of shear reinforcement to a longitudinal axis, (degree)
\, A_v=Area of shear reinforcement, (in.2)
\, f_y=Minimum yield strength of tension shear reinforcement, (ksi)


Design sections near supports

Where a reaction force in the direction of the applied shear introduces compression into the end region of girder, the location of the critical section for shear is measured from the internal face of support a distance, dv. Otherwise, the design section shall be taken at the internal face of the support.


Where:


\, d_v = effective shear depth taken as the distance, measured perpendicular to the neutral axis, between the resultants of the tensile and compressive forces due to flexure; it need not be taken to be less than the greater of 0.9de and 0.72h.


Girder regions requiring shear reinforcement

Girder shear reinforcement, usually consisting of stirrups, shall be provided where:


\, V_u > 0.50 \phi (V_c + V_p)


Where:

\, V_u=Factored shear force from Strength I load combination, (kips)
\, V_c=Nominal concrete shear resistance, (kips)
\, V_p=Component of prestressing force in the direction of shear force, (kips)
\, \phi =
=
Shear resistance factor

0.9 for normal weight concrete


Shear Reinforcement Limits


Minimum reinforcement

Area of shear reinforcement shall not be less than:


\, A_v \ge 0.0316 \Bigg( \frac{b_v s}{f_y} \Bigg) \sqrt{f'_c}


Where:

\, A_v=Area of shear reinforcement, (in.2)
\, b_v=Thickness of web, (in.)
\, s=Spacing of shear reinforcement, (in.)
\, f'_c=Final concrete compressive strength, (ksi)


Maximum reinforcement

Maximum spacing of shear reinforcement shall be determined as:
If \, v_u<0.125 f'_c, then \, s_{max} = 0.8 d_v \le 24.0^{\prime\prime}


If \, v_u \ge 0.125 f'_c, then \, s_{max} = 0.4 d_{v} \le 12.0^ {\prime\prime}


Where:

\, d_v = Effective shear depth taken as the distance measured perpendicular to the neutral axis, between the resultants of tensile and compressive forces due to flexure, (in.)
\, v_u=Shear stress on concrete, (ksi)
smax=Maximum spacing of shear reinforcement, (in.)


Shear stress on concrete shall be determined as:


\, v_u = \frac {V_u - \phi V_p}{\phi b_v d_v}


\, d_v = \Bigg( d_e - \frac{a}{2} \Bigg) \ge larger of \begin{cases}0.9 d_e\\0.72h\end{cases}


Where:

\, v_u=Shear stress on concrete, (ksi)
\, V_u=Factored shear from Strength I load combination, (kips)
\, \phi =
=
Shear resistance factor

0.9 for normal weight concrete

\, b_v=Thickness of web, (in.)
\, V_p=Component of prestressing force in the direction of shear force, (kips)
\, d_v = Effective shear depth taken as the distance measured perpendicular to the neutral axis, between the resultants of tensile and compressive forces due to flexure, (in.)
 =\, \frac{M_n}{A_s f_y + A_{ps} f_{ps}}
\, d_e=Distance from extreme compression fiber to the centroid of tensile force in the tensile reinforcement, (in.)
\, h=Total height of girder including slab thickness, (in.)


Girder-Slab Interface

The horizontal shear between the girder and slab shall be determined as specified in LRFD 5.8.4.3. The nominal horizontal shear resistance of the interface plane shall be taken as specified in LRFD 5.8.4.1. Minimum interface shear reinforcement shall be provided as specified in LRFD 5.8.4.4. The parameters used in determining the nominal horizontal shear resistance shall be taken as specified for a “cast-in-place concrete slab on clean concrete girder surfaces, free of laitance with surface roughened to an amplitude of 0.25 inch.”

The interface shear shall be resisted by extending and anchoring the vertical shear reinforcement into the slab. If the resistance provided by extending the vertical shear reinforcement is inadequate then additional U-bars may be provided as shown for a MoDOT Standard Girder Type 7 in EPG 751.22.3.6 Girder Reinforcement.

For NU Girders the edges of the top of girder flange are intentionally debonded (see figure below) and shall not be included when determining the nominal horizontal shear resistance. See EPG 751.50 Standard Detailing Notes H2c2.10 for specifics about the debonded width for NU Girders. Similarly, for all other prestressed girders, the joint filler width supporting precast panels shall be considered debonded and excluded when determining the interface resistance.

NU Girder Debonding Limits
NU Girder Debonding Limits

Pretensioned anchorage zones

The bursting resistance of anchorage zones provided by vertical reinforcement (i.e., B2 bars, WWF, G402 bars) in the ends of prestressed girders at the service limit state shall be taken as:


\, P_r = f_s A_s \ge 0.04F_{po}


Where:

\, f_s=Stress in mild steel not exceeding 20 ksi
\, A_s=Total area of vertical reinforcement located within a minimum distance of h/4 from the end of the girder where h is overall depth of precast member as shown below.
\, F_{po}=Prestressing force at transfer


MoDOT Standard Girder Anchorage Zone and Confinement Reinforcement
MoDOT Standard Girder
Anchorage Zone and Confinement Reinforcement


Confinement reinforcement

Reinforcement (i.e., D1 bars or G301 bars, not shown) shown in the figure above shall be placed to confine the prestressing strands in the bottom flange for a minimum distance of 1.5d from the end of beam.

The reinforcement shall not be less than #3 deformed bar, with spacing not exceeding 6.0 inches and shaped to enclose the strands.

MoDOT extends the use of D1 and G301 bars for the full length of girders.

751.22.2.5 Deformations

Criteria for deflection

For investigating maximum absolute deflection, all design lanes shall be loaded, and all supporting components should be assumed to deflect equally.

For composite design, the design cross-section should include the entire width of the roadway and the structurally continuous portions of railings, sidewalks, and median barriers. Note that safety barrier curbs are usually discontinuous over the bents. For skewed bridges, a right cross-section may be used.

Service I load combination shall be used. Dynamic load allowance shall be applied.


See EPG 751.2.4.2 Live Load Deflection Limits.


Calculation of deflection and camber

Deflection and camber calculations shall consider all internal loads (i.e., prestressing, concrete creep, and shrinkage) and external loads such as dead loads and live loads.


Camber is an upward displacement caused by moment due to prestressing forces. Deflection is a downward displacement due to external loads. Therefore, both camber and deflection shall be considered in making an appropriate adjustment for final profile grade on the bridge.


Initial camber at transfer at midspan

Total initial camber at transfer due to self-weight of girder and prestressing forces shall be determined as:


\, \Delta_{IC} = \Delta_g + \Delta_{SS} + \Delta_{HS}


Where:

\, \Delta_{IC}= Initial camber at transfer
\, \Delta_g= Deflection due to self-weight of girder
\, \Delta_{SS}= Camber due to prestressing straight strands
\, \Delta_{HS}= Camber due to prestressing harped strands


Note: Positive and negative values indicate downward and upward displacements, respectively.


Camber at midspan after strand release (Estimated at 7 days)

Theoretical camber of girder after strand release due to self-weight of girder and prestressing forces shall be determined at 7 days as:

\, \Delta_7 = \Delta_{IC} + \Delta_{CR\ at\ 7\ days}


Where:

\, \Delta_7= Camber at 7 days after strand release with creep
\, \Delta_{CR\ at\ 7\ days}= Time - dependent camber due to creep at 7 days

Note: Camber is calculated 7 days after strand release to allow sufficient time for inspection. See EPG 1029 Fabricating Prestressed Concrete Members for Bridges.

Camber at midspan after erection (Estimated at 90 days)

Theoretical camber of girder after erection due to self-weight of girder and prestressing forces shall be determined at 90 days as:

\, \Delta_{90} = \Delta_{IC} + \Delta_{CR\ at\ 90\ days}


Where:

\, \Delta_{90}= Camber at 90 days after strand release with creep
\, \Delta_{CR\ at\ 90\ days}= Time - dependent camber due to creep at 90 days


Final camber at midspan after slab is poured

Total deformation after slab is poured can be determined as the sum of theoretical camber of girder after erection (90 days) and deflections due to slab and concentrated loads (haunch, diaphragms, etc.) before composite action between slab and girder.

\, \Delta_{FC} = \Delta_{90} + \Delta_S + \sum \Delta_C


Where:

\, \Delta_{FC}=Final camber after slab is poured
\, \Delta_s=Deflection due to weight of slab
\, \sum \Delta_c=Deflection due to concentrated loads (haunch, diaphragms, etc.)


Final camber along span length

Deformations along the span length can be approximately determined as a product of final camber at midspan times correction factors.

\, \Delta_{0.10}=0.3140 \, \Delta_{FC} at span fraction of 0.10
\, \Delta_{0.20}=0.5930 \, \Delta_{FC} at span fraction of 0.20
\, \Delta_{0.25}=0.7125 \, \Delta_{FC} at span fraction of 0.25
\, \Delta_{0.30}=0.8130 \, \Delta_{FC} at span fraction of 0.30
\, \Delta_{0.40}=0.9520 \, \Delta_{FC} at span fraction of 0.40
\, \Delta_{0.50}=1.0000 \, \Delta_{FC} at span fraction of 0.50


Calculation of camber (upward)

Camber at midspan due to strand forces is determined as the following: For straight strands,


\, \Delta_{SS} = \Delta_{ss-j} + \Delta_{ss-l}


Where:   \, \Delta_{ss-j} = \frac{F_{1-j} e_1 L^2}{8 E_{ci} I_{tri}}     \, \Delta_{ss-l} = \frac{F_{1-l} e_1 L^2}{8 E_c I_{tr}}


Where:

\, F_{1-j}= Total prestressing force of straight strands at transfer (including losses due to elastic shortening), (kips)
\, F_{1-l}= Total prestressing force in straight strands due to time-dependent losses prior to slab placement (kips). Opposite in sign to \, F_{1-j}, typically.
\, L= Distance between centerlines of bearing pads, (in.)
\, E_{ci}= Initial concrete modulus of elasticity based on \, f'_{ci}, (ksi)
\, E_c= Final concrete modulus of elasticity based on \, f'_c (ksi)
\, I_{tri}= Moment of inertia of transformed non-composite section computed based on \, E_{ci}, (in.4)
\, I_{tr}= Moment of inertia of transformed non-composite section based on \, E_c, (in.4)
\, e_1= Eccentricity between centroid of straight strands (CSS) and center of gravity of transformed non-composite section (CGB) as shown in Figure below, (in.)


For two-point harped strands,


\, \Delta_{HS} = \Delta_{HS-j} + \Delta_{HS-l}


Where:   \, \Delta_{HS-j} = \frac {F_{2-j} e_2 L^2}{8 E_{ci} I_{tri}} - \frac {F_{2-j}(e_2 + e_3) a^2}{6 E_{ci} I_{tri}}     \, \Delta_{HS-l} = \frac {F_{2-l} e_2 L^2}{8 E_c I_{tr}} - \frac {F_{2-l}(e_2 + e_3) a^2}{6 E_c I_{tr}}


a = (Lb) / 2


Where:

\, F_{2-j}= Total prestressing force of harped strands at transfer (including loss due to elastic shortening), (kips)
\, F_{2-l}= Total prestressing force of harped strands due to time-dependent losses prior to slab placement (kips)
\, b= Length between harped points, (in.)
\, e_2= Eccentricity between centroid of harped strands (CHS) and center of gravity of transformed non-composite section (CGB) at midspan as shown in Figure below, (in.)
\, e_3= Eccentricity between centroid of harped strands (CHS) and center of gravity of transformed non-composite section (CGB) at the end of girder as shown in Figure below, (in.)


Image:751.22_details_of_girder_showing_distances_and_eccentricities_used_in_camber_calculations.gif


Details of girder showing distances and eccentricities used in camber calculations


Calculations of deflections (downward)

Deflections at midspan due to dead loads are determined as the following: For self-weight of girder,


\, \Delta_g = \frac {5 W_g L^4}{384 E_{ci} I_{tri}}


Where:

Wg=Uniform load due to self-weight of girder, (kip/in.)


For self-weight of slab,


\, \Delta_s = \frac {5 W_s L^4}{384 E_{c} I'_{tr}}


Where:

\, W_s=Uniform load due to self-weight of slab, (kip/in.)

Weight of additional slab haunch may be treated as uniform or concentrated load as appropriate. Diaphragm weight should be treated as concentrated load.

For one concentrated load at midspan,


\, \Delta_c = \frac {PL^3}{48 E_c I'_{tr}}


For two equal concentrated loads,


\, \Delta_c = \frac {Px}{24 E_c I'_{tr}} (3L^2 - 4x^2)


Where:

\, P= Concentrated load due to diaphragm and/or additional slab haunch, (kips)
\, x= Distance from the centerline of bearing pad to the applied load, P, (in.)

Creep coefficient

Research has indicated that high strength concrete (HSC) undergoes less ultimate creep and shrinkage than conventional concrete.

Creep is a time-dependent phenomenon in which deformation increases under a constant stress. Creep coefficient is a ratio of creep strain over elastic strain, and it can be estimated as follows:

\, \Psi(t,t_i)= \, 1.9k_s k_{hc} k_f k_{td} t_{i}^{-0.118}
\, k_s= \, 1.45 - 0.13(v/s)>= 1.0
\, k_{hc}= \, 1.56 - 0.008H
\, k_f= \, 5/(1+f'_{ci})
\, k_{td}= \, t/(61 - 4f'_{ci} + t)


Where:

\, \Psi= Creep coefficient.
\, H= 70, Average annual ambient relative humidity
\, t = Maturity of concrete, (days)
    Use 7 days for camber design after strand release
    Use 90 days for camber design after erection
\, t_i = Age of concrete when a load is initially applied, (days)
    Use 0.75 days for camber design.
\, v/s= Volume-to-surface area ratio, (in.)
\, f'_{ci}= Initial girder concrete compressive strength, (ksi)


\, \Delta_{CR} = \frac{(M_g - F_{1-j} e_1 - F_{2-j} e_2) \Psi L^2}{8 E_{ci} I_{tri}}

Where:

\, M_g= Moment due to girder weight at mid span.

751.22.3 Details

751.22.3.1 Reinforcement Criteria

Minimum Concrete Cover

  • 2.0" (Min.) to centerline of strands
  • 1.0" for stirrups


Minimum Bend Diameter for Stirrups

  • #3 through #5 bars = 4.0 x Nominal Bar Diameter.
  • Deformed wire larger than D6 = 4.0 x Nominal Wire Diameter


Minimum Spacing of Reinforcement Bars and Wires For precast concrete, the clear distance between parallel bars in a layer shall not be lesser than:

  • Nominal Bar Diameter or Nominal Wire Diameter
  • 1.33 x Maximum Aggregate Size
  • 1.0"


Minimum Spacing of Prestressing Strands Spacing between each pretressing strand shall not be less than the larger of:

  • A clear distance of 1.33 x Maximum Aggregate Size
  • Center-to-center spacing of 2" for 0.6" strand diameter
  • Center-to-center spacing of 1.75" for 0.5" strand diameter

751.22.3.2 MoDOT Standard Girders

751.22.3.2.1 Beam Type 2 Dimensions/Strand Arrangements

Image:751.22 Beam Type 2 dim & Girders 2A & 2B.gif


GIRDERS 2A THRU 2C

A = 310.9 SQ. IN.
Yb = 14.08 IN.
I = 33,974 IN.4

GIRDER 2A

(11 STRANDS)

GIRDER 2B

(12 STRANDS)


Image:751.22_Beam_Type_2_Girder_2C.gif

GIRDERS 2C
(14 STRANDS)

Image:751.22_Beam_Type_2_Girders_Sequence_No_2A_thru_2C_Table.gif
 
NOTE: Investigate the possibility of using all straight strands when strength check of a hold-down device exceeds allowable.
Strand arrangements shown for Girders 2A thru 2C have straight strands only.

Strand arrangements other than those shown may be investigated by the designer.



A = 310.9 SQ. IN.

Yb = 14.08 IN.
I = 33,974 IN.4

GROUP I



 
GROUP II
Numbers shown on girders
relate to strand locations.


ATTENTION: Location of harped strands shown in top flange are at end of girder and harped strands in bottom flange are at centerline.


If the web thickness is required to be increased, then the top and bottom flanges are to be increased by the same amount. (1" increments, 2" max.)

751.22.3.2.2 Beam Type 3 Dimensions/Strand Arrangements

Image:751.22_Beam_Type_3_Girders_3A_thru_3B.gif


GIRDERS 3A THRU 3B

A = 381.9 SQ. IN.
Yb = 17.08 IN.
I = 61,841 IN.4

GIRDER 3A

(11 STRANDS)

GIRDER 3B

(12 STRANDS)


Image:751.22_Beam_Type_3_Girders_Sequence_No_3A_thru_3B_Table.gif


Note: Investigate the possibility of using all straight strands when strength check of a hold-down device exceeds allowable.
Strand arrangements shown for Girders 3A thru 3B have straight strands only.

Strand arrangements other than those shown may be investigated by the designer.


Image:751.22_Beam_Type_3_Girders_dim_&_Group_I.gif


A = 381.9 SQ. IN.

Yb = 17.08 IN.
I = 61,841 IN.4

GROUP I
Image:751.22_Beam_Type_3_Girders_Group_II.gif
 
GROUP II
Numbers shown on girders
relate to strand locations.


ATTENTION: Location of harped strands shown in top flange are at end of girder and harped strands in bottom flange are at centerline.

If the web thickness is required to be increased, then the top and bottom flanges are to be increased by the same amount. (1" increments, 2" max.)

751.22.3.2.3 Beam Type 4 Dimensions/Strand Arrangements

Image:751.22_Beam_Type_4_Girders_4A_&_4B.gif


GIRDERS 4A THRU 4C

A = 428.9 SQ. IN.
Yb = 19.54 IN.
I = 92,450 IN.4

GIRDER 4A

(10 STRANDS)

GIRDER 4B

(11 STRANDS)


Image:751.22_Beam_Type_4_Girders_4C.gif

GIRDERS 4C
(13 STRANDS)

Image:751.22_Beam_Type_4_Girders_Sequence_No_4A_thru_4C_Table.gif
 
NOTE: Investigate the possibility of using all straight strands when strength check of a hold-down device exceeds allowable.
Strand arrangements shown for Girders 4A thru 4C have straight strands only.

Strand arrangements other than those shown may be investigated by the designer.


Image:751.22_Beam_Type_4_Girders_dim_&_Group_I.gif


A = 428.9 SQ. IN.

Yb = 19.54 IN.
I = 92,450 IN.4

GROUP I


Image:751.22_Beam_Type_4_Girders_Group_II.gif
 
GROUP II
Numbers shown on girders
relate to strand locations.


ATTENTION: Location of harped strands shown in top flange are at end of girder and harped strands in bottom flange are at centerline.


If the web thickness is required to be increased, then the top and bottom flanges are to be increased by the same amount. (1" increments, 2" max.)

751.22.3.2.4 Beam Type 6 Dimensions/Strand Arrangements

Image:751.22_Beam_Type_6_dimensions.gif  
\, A=643.6 Sq. In.
\, Y_b=25.92 In.
\, I=235,735 In.4


Image:751.22_Beam_Type_6_Group_I.gif
 

GROUP I

Numbers shown on girders
relate to strand locations.


ATTENTION: Location of harped strands shown in top flange are at end of girder and harped strands in bottom flange are at centerline.

If the web thickness is required to be increased, then the top and bottom flanges are to be increased by the same amount. (1" increments, 2" max.)

751.22.3.2.5 Beam Type 7 Dimensions/Strand Arrangements

Image:751.22_Beam_Type_7_dimensions.gif  
\, A=787.4 Sq. In.
\, Y_b=37.58 In.
\, I=571,047 In.4


Image:751.22_Beam_Type_7_Group_I.gif
 

GROUP I

Numbers shown on girders
relate to strand locations.


ATTENTION: Location of harped strands shown in top flange are at end of girder and harped strands in bottom flange are at centerline.

751.22.3.3 NU Standard Girders

NU Girder Dimensions/Strand Arrangements
* Strands shall be placed on outer edge to help place confinement steel
* Strands shall be placed on outer edge to help place confinement steel
Note: Strand arrangements shall start at the bottom row and then move up for the most efficient design.

751.22.3.4 Beam Section Properties Tables - Conventional Concrete Strength

The properties of prestressed I-girders in the following tables are valid for \, f'_{ci} = 4.5 ksi and \,f'_c = 6 ksi. The modular ratio , \, n, is 8 for the initial moment of inertia, \, I_{initial}, and 7 for the final moment of inertia, \, I_{final}.

Note: Moments of inertia, \, I_{initial} and \, I_{final} are computed based on transformed non-composite section and are used in camber calculations.

Definitions used in tables are:

Section Area=Gross area of girder, (in.2)
Section \, Y_b =Distance from bottom of girder to center of gravity of non-transformed non-composite section, (in.)
\, I_{nontransformed} =Moment of inertia of non-transformed non-composite section, (in.4)
Depth=Height of girder, (in.)
Strand size=Strand diameter, (in.)
e1*=Eccentricity between centroid of straight strands (CSS) and center of gravity of non-transformed non-composite section (CGB) as shown in figure below, (in.)
e2*=Eccentricity between centroid of harped strands (CHS) and center of gravity of non-transformed non-composite section (CGB) at midspan as shown in figure below, (in.)
e3*=Eccentricity between centroid of harped strands (CHS) and center of gravity of non-transformed non-composite section (CGB) at the end of girder as shown in figure below, (in.)


\, * A more accurate value can be used based on transformed non-composite section. The final camber calculation will not be significantly different using values between transformed and non-transformed sections.


Image:751.22_Girder_Plan_showing_strands.gif


Steps for detailing strand patterns from Prestressed Beam Tables

  1. For strand locations at mid-span of girder: Look up the "Total Number of Strands" value for the corresponding strand pattern number. The strands will then be located at that number and all numbers below that number. Ex. For 14 total strands, the strands will be placed at all locations numbered ≤14.
  2. For harped strand locations at end of girder: Look up the "Number of Harped Strands" value for the corresponding strand pattern number. The strands will then be located at that number and all numbers below that number. Ex. For 6 harped strands, the strands will be placed at all locations numbered ≤6.


Image:751.22_Girder_Section_showing_strands.gif
GROUP I



Section Properties
Beam Type 2 -- 6" Web


Section Area = 310.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 14.08in
\, I_{nontransformed} = 33,974in4
Depth= 32in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


         Iinitial Ifinal
  # T H S e1 e2 e3 A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars,
2-#6
Group 1 8 4 4 11.08 11.08 13.92 36,147 36,627 35,837 36,248
I 2 10 4 6 11.41 11.08 13.92 36,453 36,938 36,100 36,515
  3 12 6 6 11.41 10.08 12.92 36,587 37,075 36,215 36,632
  4 14 6 8 11.08 10.08 12.92 36,794 37,286 36,394 36,814
  5 16 8 8 11.08 9.08 11.92 36,866 37,360 36,456 36,878
  6 18 8 10 10.48 9.08 11.92 36,994 37,491 36,568 36,992
Group 7 8 2 6 11.41 10.08 14.92 36,147 36,627 35,837 36,248
II 8 10 2 8 11.58 10.08 14.92 36,453 36,938 36,100 36,515
  9 12 4 8 11.08 11.08 13.92 36,663 37,151 36,280 36,698
  10 14 4 10 11.28 9.08 13.92 36,794 37,286 36,394 36,814
  11 16 6 10 11.28 8.08 12.92 36,866 37,360 36,456 36,878
  12 18 6 12 10.75 8.08 12.92 36,994 37,491 36,568 36,992
  13 20 6 14 10.65 6.08 12.92 37,024 37,522 36,594 37,019


Section Properties
Beam Type 2 -- 7" Web


Section Area = 342.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 14.26in
\, I_{nontransformed} = 36,812in4
Depth= 32in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_{c} = 6ksi


         Iinitial Ifinal
 #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184411.2611.2613.7438,99439,46438,68339,085
I 2104611.5911.2613.7439,31039,78438,95439,360
 3126611.5910.2612.7439,45039,92739,07539,482
 4146811.2610.2612.7439,66640,14639,26139,671
 5168811.269.2611.7439,74240,22539,32739,739
 61881010.669.2611.7439,87740,36339,44439,858
Group 782611.5910.2614.7438,99439,46438,68339,085
II 8102811.7610.2614.7439,31039,78438,95439,360
 9124811.2611.2613.7439,52840,00539,14239,550
 101441011.469.2613.7439,66640,14639,26139,671
 111661011.468.2612.7439,74240,22539,32739,739
 121861210.938.2612.7439,87740,36339,44439,858
 132061410.836.2612.7439,91039,47339,47339,888


Section Properties
Beam Type 2 -- 8" Web


Section Area = 374.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 14.41in
\, I_{nontransformed} = 39,632in4
Depth= 32in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


         Iinitial Ifinal
 #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184411.4111.4113.5941,82342,28341,51041,905
I 2104611.7411.4113.5942,14742,61141,78942,186
 3126611.7410.4112.5942,29242,76041,91442,313
 4146811.4110.4112.5942,51542,98542,10642,508
 5168811.419.4111.5942,59643,06842,17642,579
 61881010.819.4111.5942,73743,21242,29842,703
Group 782611.7410.4114.5941,82342,28341,51041,905
II 8102811.9110.4114.5942,14742,61141,78942,186
 9124811.4111.4113.5942,37142,83941,98242,382
 101441011.619.4113.5942,51542,98542,10642,508
 111661011.618.4112.5942,59643,06842,17642,579
 121861211.088.4112.5942,73743,21242,29842,703
 132061410.986.4112.5942,77243,24942,32942,736


Section Properties
Beam Type 3 -- 6" Web

Section Area = 381.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 17.08in
\, I_{nontransformed} = 61,841in4
Depth= 39in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184413.0814.0817.9265,17965,93064,70265,346
I 2104613.7514.0817.9265,65966,41565,11465,762
 3124813.5814.0817.9266,01466,77665,42166,072
 4146813.5813.0816.9266,26567,03265,63766,292
 51661013.4813.0816.9266,61467,38665,93866,597
 61881013.4812.0815.9266,77667,55266,07966,740
 72081213.0812.0815.9267,02067,79966,29066,954
 82281412.5112.0815.9267,17867,96166,42767,095
 924101412.5111.0814.9267,27068,05666,50867,177
Group 1082613.7513.0818.9265,17965,93064,70265,346
II 11102814.0813.0818.9265,65966,41565,11465,762
 121221013.8813.0818.9266,01466,77665,42166,072
 131441013.4814.0817.9266,36667,13465,72466,379
 141641213.7512.0817.9266,61467,38665,93866,597
 151861213.7511.0816.9266,77667,55266,07966,740
 162061413.3711.0816.9267,02067,79966,29066,954
 172261612.8311.0816.9267,17867,96166,42767,095
 182481612.8310.0815.9267,27068,05666,50867,177


Section Properties
Beam Type 3 -- 7" Web

Section Area = 420.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 17.31in
\, I_{nontransformed} = 66,991in4
Depth= 39in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184413.3114.3117.6970,34371,07769,86570,493
I 2104613.9814.3117.6970,83871,57770,28970,922
 3124813.8114.3117.6971,20771,95170,60771,243
 4146813.8113.3116.6971,46972,21870,83371,473
 51661013.7113.3116.6971,83272,58571,14671,789
 61881013.7112.3115.6972,00472,76071,29571,940
 72081213.3112.3115.6972,25973,01971,51672,164
 82281412.7412.3115.6972,42773,19071,66272,312
 924101412.7411.3114.6972,52673,29271,74972,401
Group 1082613.9813.3118.6970,34371,07769,86570,493
II 11102814.3113.3118.6970,83871,57770,28970,922
 121221014.1113.3118.6971,20771,95170,60771,243
 131441013.7114.3117.6971,57272,32270,92271,562
 141641213.9812.3117.6971,83272,58571,14671,789
 151861213.9811.3116.6972,00472,76071,29571,940
 162061413.6011.3116.6972,25973,01971,51672,164
 172261613.0611.3116.6972,42773,19071,66272,312
 182481613.0610.3115.6972,52673,29271,74972,401


Section Properties
Beam Type 3 -- 8" Web

Section Area = 459.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 17.49in
\, I_{nontransformed} = 72,106in4
Depth= 39in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184413.4914.4917.5175,47076,19174,99075,607
I 2104614.1614.4917.5175,97776,70375,42576,046
 3124813.9914.4917.5176,35777,08775,75276,376
 4146813.9913.4916.5176,62877,36375,98676,613
 51661013.8913.4916.5177,00277,74076,30876,939
 61881013.8912.4915.5177,18277,92376,46477,096
 72081213.4912.4915.5177,44678,19176,69277,328
 82281412.9212.4915.5177,62278,37076,84577,483
 924101412.9211.4914.5177,72878,47976,93877,577
Group 1082614.1613.4918.5175,47076,19174,99075,607
II 11102814.4913.4918.5175,97776,70375,42576,046
 121221014.2913.4918.5176,35777,08775,75276,376
 131441013.8914.4917.5176,73377,46876,07676,704
 141641214.1612.4917.5177,00277,74076,30876,939
 151861214.1611.4916.5177,18277,92376,46477,096
 162061413.7811.4916.5177,44678,19176,69277,328
 172261613.2411.4916.5177,62278,37076,84577,483
 182481613.2410.4915.5177,72878,47976,93877,577


Section Properties
Beam Type 4 -- 6" Web

Section Area = 428.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 19.54in
\, I_{nontransformed} = 92,450in4
Depth= 45in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184415.5416.5421.4697,07798,11896,41697,308
I 2104616.2116.5421.4697,72798,77596,97497,872
 3124816.0416.5421.4698,23199,28697,40898,310
 4146816.0415.5420.4698,60899,66997,73398,640
 51661015.9415.5420.4699,103100,17098,16099,071
 61881015.9414.5419.4699,368100,44198,39099,305
 72081215.5414.5419.4699,735100,81398,70799,626
 82281414.9714.5419.4699,995101,07898,93399,856
 92481615.2912.5419.46100,168101,25499,083100,009
 1026101615.2911.5418.46100,271101,36099,174100,102
 1128101815.329.5418.46100,323101,41499,220100,149
Group 1282616.2115.5422.4697,07798,11896,41697,308
II 13102816.5415.5422.4697,72798,77596,97497,872
 14124816.0416.5421.4698,23199,28697,40898,310
 151441015.9416.5421.4698,73099,79297,83898,745
 161641216.2114.5421.4699,103100,17098,16099,071
 171661015.9415.5420.4699,103100,17098,16099,071
 181861216.2113.5420.4699,368100,44198,39099,305
 192061415.8313.5420.4699,735100,81398,70799,626
 202261615.2913.5420.4699,995101,07898,93399,856
 212461815.3211.5420.46100,168101,25499,083100,009
 222662015.149.5420.46100,271101,36099,174100,102
 232681815.3210.5419.46100,271101,36099,174100,102
 242862214.817.5420.46100,323101,41499,220100,149
 252882015.148.5419.46100,323101,41499,220100,149
 263082214.816.5419.46100,341101,43399,236100,166
 273282414.374.5419.46100,342101,43599,238100,168


Section Properties
Beam Type 4 -- 7" Web

Section Area = 473.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 19.82in
\, I_{nontransformed} = 100,400in4
Depth= 45in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184415.8216.8221.18105,048106,065104,384105,256
I 2104616.4916.8221.18105,719106,743104,960105,837
 3124816.3216.8221.18106,242107,272105,410106,291
 4146816.3215.8220.18106,636107,671105,750106,635
 51661016.2215.8220.18107,151108,192106,193107,083
 61881016.2214.8219.18107,431108,476106,436107,328
 72081215.8214.8219.18107,815108,866106,768107,664
 82281415.2514.8219.18108,090109,145107,007107,906
 92481615.5712.8219.18108,275109,334107,168108,070
 1026101615.5711.8218.18108,388109,449107,266108,171
 1128101815.609.8218.18108,446109,510107,318108,224
Group 1282616.4915.8222.18105,048106,065104,384105,256
II 13102816.8215.8222.18105,719106,743104,960105,837
 14124816.3216.8221.18106,242107,272105,410106,291
 151441016.2216.8221.18106,760107,796105,857106,742
 161641216.4914.8221.18107,151108,192106,193107,083
 171661016.2215.8220.18107,151108,192106,193107,083
 181861216.4913.8220.18107,431108,476106,436107,328
 192061416.1113.8220.18107,815108,866106,768107,664
 202261615.5713.8220.18108,090109,145107,007107,906
 212461815.6011.8220.18108,275109,334107,168108,070
 222662015.429.8220.18108,388109,449107,266108,171
 232681815.6010.8219.18108,388109,449107,266108,171
 242862215.097.8220.18108,446109,510107,318108,224
 252882015.428.8219.18108,446109,510107,318108,224
 263082215.096.8219.18108,469109,533107,338108,245
 273282414.654.8219.18108,472109,537107,341108,248


Section Properties
Beam Type 4 -- 8" Web

Section Area = 518.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 20.06in
\, I_{nontransformed} = 108,288in4
Depth= 45in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184416.0617.0620.94112,955113,952112,289113,143
I 2104616.7317.0620.94113,645114,648112,881113,739
 3124816.5617.0620.94114,185115,193113,345114,208
 4146816.5616.0619.94114,594115,607113,698114,563
 51661016.4616.0619.94115,126116,144114,156115,026
 61881016.4615.0618.94115,419116,442114,409115,282
 72081216.0615.0618.94115,818116,846114,755115,631
 82281415.4915.0618.94116,107117,138115,004115,884
 92481615.8113.0618.94116,303117,337115,175116,057
 1026101615.8112.0617.94116,424117,461115,281116,165
 1128101815.8410.0617.94116,489117,528115,338116,223
Group 1282616.7316.0621.94112,955113,952112,289113,143
II 13102817.0616.0621.94113,645114,648112,881113,739
 14124816.5617.0620.94114,185115,193113,345114,208
 151441016.4617.0620.94114,720115,734113,806114,673
 161641216.7315.0620.94115,126116,144114,156115,026
 171661016.4616.0619.94115,126116,144114,156115,026
 181861216.7314.0619.94115,419116,442114,409115,282
 192061416.3514.0619.94115,818116,846114,755115,631
 202261615.8114.0619.94116,107117,138115,004115,884
 212461815.8412.0619.94116,303117,337115,175116,057
 222662015.6610.0619.94116,424117,461115,281116,165
 232681815.8411.0618.94116,424117,461115,281116,165
 242862215.338.0619.94116,489117,528115,338116,223
 252882015.669.0618.94116,489117,528115,338116,223
 263082215.337.0618.94116,515117,555115,361116,247
 273282414.895.0618.94116,520117,560115,366116,252


Section Properties
Beam Type 6 -- 6.5" Web

Section Area = 643.6in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 25.92in
\, I_{nontransformed} = 235,735in4
Depth= 54in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


        IinitialIfinal
 #THSe1e2e3A1 Bars
2-#6
A1 Bars
2-#6
Group 11441023.5222.9223.08248,115246,353
I 21641223.2522.9223.08249,115247,213
 31861223.2521.9222.08249,933247,918
 42061423.0621.9222.08250,920248,769
 52261622.9221.9222.08251,901249,616
 62481622.9220.9221.08252,545250,173
 72681822.5920.9221.08253,342250,862
 82882022.3220.9221.08254,133251,547
 930102022.3219.9220.08254,626251,975
 1032102222.1019.9220.08255,408252,653
 1134102421.7519.9220.08256,032253,195
 1236102621.4619.9220.08256,651253,734
 1338122621.4618.9219.08257,011254,048


Section Properties
Beam Type 6 -- 7.5" Web

Section Area = 697.6in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 26.00in
\, I_{nontransformed} = 248,915in4
Depth= 54in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


        IinitialIfinal
 #THSe1e2e3A1 Bars
2-#6
A1 Bars
2-#6
Group 11441023.6023.0023.00262,852260,864
I 21641223.3323.0023.00263,868261,737
 31861223.3322.0022.00264,701262,454
 42061423.1422.0022.00265,707263,319
 52261623.0022.0022.00266,706264,180
 62481623.0021.0021.00267,365264,749
 72681822.6721.0021.00268,178265,452
 82882022.4021.0021.00268,987266,150
 930102022.4020.0020.00269,493266,589
 1032102222.1820.0020.00270,294267,282
 1134102421.8320.0020.00270,933267,836
 1236102621.5420.0020.00271,569268,387
 1338122621.5419.0019.00271,941268,712


Section Properties
Beam Type 6 -- 8.5" Web

Section Area = 751.6in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 26.07in
\, I_{nontransformed} = 262,087in4
Depth= 54in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


        IinitialIfinal
 #THSe1e2e3A1 Bars
2-#6
A1 Bars
2-#6
Group 11441023.6723.0722.93276,043274,052
I 21641223.4023.0722.93277,068274,932
 31861223.4022.0721.93277,908275,656
 42061423.2122.0721.93278,922276,528
 52261623.0722.0721.93279,930277,396
 62481623.0721.0720.93280,596277,971
 72681822.7421.0720.93281,418278,680
 82882022.4721.0720.93282,236279,386
 930102022.4720.0719.93282,750279,831
 1032102222.2520.0719.93283,559280,531
 1134102421.9020.0719.93284,207281,093
 1236102621.6120.0719.93284,851281,651
 1338122621.6119.0718.93285,230281,981

Section Properties
Beam Type 7 -- 6" Web
Bulb-Tee Girder

Section Area = 787.4in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 37.58in
\, I_{nontransformed} = 571,047in4
Depth= 72.5in
Strand Size= ½in
\, f'_{ci} = 4.5ksi
\, f'_c = 6ksi


Cont.        IinitialIfinal
Span #THSe1e2e3A1 Bars
4-#6
A1 Bars
4-#6
Group 11441035.5834.5829.92603,636598,983
I 21641235.2534.5829.92606,025601,033
 31861235.2533.5828.92608,125602,838
 42061435.0133.5828.92610,490604,871
 52261634.8333.5828.92612,843606,895
 62481634.8332.5827.92614,652608,453
 72681834.6932.5827.92616,981610,459
 82882034.5832.5827.92619,299612,457
 930102034.5831.5826.92620,839613,788
 1032102234.3131.5826.92622,864615,536
 1134102434.0831.5826.92624,878617,276
 1236102633.8931.5826.92626,881619,009
 1338102833.5831.5826.92628,622620,517
 1440122833.5830.5825.92629,902621,627

751.22.3.5 Beam Section Properties Tables - Higher Concrete Strength

The properties of prestressed I-girders in the following tables are valid for \, f'_{ci} = 5 ksi and \, f'_c = 7 ksi. The modular ratio , \, n, is 7 for the initial moment of inertia, \, I_{initial}, and 6 for the final moment of inertia, \, I_{final}.

Note: Moments of inertia, \, I_{initial} and \, I_{final} are computed based on transformed non-composite section and are used in camber calculations. A1 Bar locations are assumed at 3" from the top of girder.

Definitions used in tables are:

Section Area=Gross area of girder, (in.2)
Section \, Y_b =Distance from bottom of girder to center of gravity of non-transformed non-composite section, (in.)
\, I_{nontransformed} =Moment of inertia of non-transformed non-composite section, (in.4)
Depth=Height of girder, (in.)
Strand size=Strand diameter, (in.)
e1*=Eccentricity between centroid of straight strands (CSS) and center of gravity of non-transformed non-composite section (CGB) as shown in figure below, (in.)
e2*=Eccentricity between centroid of harped strands (CHS) and center of gravity of non-transformed non-composite section (CGB) at midspan as shown in figure below, (in.)
e3*=Eccentricity between centroid of harped strands (CHS) and center of gravity of non-transformed non-composite section (CGB) at the end of girder as shown in figure below, (in.)


\, * A more accurate value can be used based on transformed non-composite section. The final camber calculation will not be significantly different using values between transformed and non-transformed sections.


Image:751.22_Girder_Plan_showing_strands.gif


Steps for detailing strand patterns from Prestressed Beam Tables

  1. For strand locations at mid-span of girder: Look up the "Total Number of Strands" value for the corresponding strand pattern number. The strands will then be located at that number and all numbers below that number. Ex. For 14 total strands, the strands will be placed at all locations numbered ≤14.
  2. For harped strand locations at end of girder: Look up the "Number of Harped Strands" value for the corresponding strand pattern number. The strands will then be located at that number and all numbers below that number. Ex. For 6 harped strands, the strands will be placed at all locations numbered ≤6.


Image:751.22_Girder_Section_showing_strands.gif
GROUP I



Section Properties
Beam Type 2 -- 6" Web


Section Area = 310.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 14.08in
\, I_{nontransformed} = 33,974in4
Depth= 32in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


         Iinitial Ifinal
  # T H S e1 e2 e3 A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars,
2-#6
Group 1 8 4 4 11.08 11.08 13.92 36,407 36,838 36,062 36,429
I 2 10 4 6 11.41 11.08 13.92 36,828 37,265 36,424 36,797
  3 12 6 6 11.41 10.08 12.92 36,983 37,424 36,559 36,935
  4 14 6 8 11.08 10.08 12.92 37,265 37,711 36,804 37,183
  5 16 8 8 11.08 9.08 11.92 37,304 37,753 36,839 37,221
  6 18 8 10 10.48 9.08 11.92 37,465 37,917 36,980 37,364
Group 7 8 2 6 11.41 10.08 14.92 36,407 36,837 36,061 36,429
II 8 10 2 8 11.58 10.08 14.92 36,829 37,265 36,425 36,797
  9 12 4 8 11.08 11.08 13.92 37,112 37,553 36,670 37,046
  10 14 4 10 11.28 9.08 13.92 37,265 37,711 36,804 37,183
  11 16 6 10 11.28 8.08 12.92 37,304 37,753 36,839 37,221
  12 18 6 12 10.75 8.08 12.92 37,466 37,918 36,981 37,365
  13 20 6 14 10.65 6.08 12.92 37,409 37,864 36,934 37,320


Section Properties
Beam Type 2 -- 7" Web


Section Area = 342.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 14.26in
\, I_{nontransformed} = 36,812in4
Depth= 32in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


         Iinitial Ifinal
 #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184411.2611.2613.7439,27239,69138,92239,281
I 2104611.5911.2613.7439,70640,13239,29739,660
 3126611.5910.2612.7439,87140,30039,44039,806
 4146811.2610.2612.7440,16540,59939,69540,064
 5168811.269.2611.7440,21140,64839,73640,108
 61881010.669.2611.7440,38240,82239,88540,259
Group 782611.5910.2614.7439,27139,69138,92139,280
II 8102811.7610.2614.7439,70740,13339,29739,660
 9124811.2611.2613.7440,00240,43239,55339,919
 101441011.469.2613.7440,16540,59939,69540,064
 111661011.468.2612.7440,21140,64839,73640,108
 121861210.938.2612.7440,38340,82339,88640,260
 132061410.836.2612.7440,33140,77339,84340,219


Section Properties
Beam Type 2 -- 8" Web


Section Area = 374.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 14.41in
\, I_{nontransformed} = 39,632in4
Depth= 32in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


         Iinitial Ifinal
 #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184411.4111.4113.5942,11442,52541,76142,113
I 2104611.7411.4113.5942,56142,97742,14642,502
 3126611.7410.4112.5942,73443,15442,29642,654
 4146811.4110.4112.5943,03943,46342,56042,921
 5168811.419.4111.5943,09143,51842,60742,970
 61881010.819.4111.5943,27043,70042,76443,129
Group 782611.7410.4114.5942,11442,52541,76142,112
II 8102811.9110.4114.5942,56242,97842,14742,502
 9124811.4111.4113.5942,86743,28842,41142,769
 101441011.619.4113.5943,03943,46342,56042,921
 111661011.618.4112.5943,09143,51842,60742,970
 121861211.088.4112.5943,27143,70142,76543,130
 132061410.986.4112.5943,22443,65542,72543,092


Section Properties
Beam Type 3 -- 6" Web

Section Area = 381.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 17.08in
\, I_{nontransformed} = 61,841in4
Depth= 39in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184413.0814.0817.9265,60366,29165,06865,656
I 2104613.7514.0817.9266,26566,96265,63866,233
 3124813.5814.0817.9266,75367,45766,06066,660
 4146813.5813.0816.9267,07767,78766,34166,945
 51661013.4813.0816.9267,55568,27166,75567,364
 61881013.4812.0815.9267,72368,44466,90367,516
 72081213.0812.0815.9268,04268,76967,18267,799
 82281412.5112.0815.9268,21868,94967,33667,957
 924101412.5111.0814.9268,26068,99467,37667,998
Group 1082613.7513.0818.9265,60466,29265,06865,657
II 11102814.0813.0818.9266,26466,96165,63766,232
 121221013.8813.0818.9266,75367,45766,06066,660
 131441013.4814.0817.9267,23667,94666,47767,082
 141641213.7512.0817.9267,55668,27266,75667,366
 151861213.7511.0816.9267,72568,44566,90467,517
 162061413.3711.0816.9268,04568,77167,18467,800
 172261612.8311.0816.9268,21768,94867,33667,956
 182481612.8310.0815.9268,25968,99367,37567,998


Section Properties
Beam Type 3 -- 7" Web

Section Area = 420.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 17.31in
\, I_{nontransformed} = 66,991in4
Depth= 39in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184413.3114.3117.6970,79271,46470,25170,826
I 2104613.9814.3117.6971,47772,15670,84171,420
 3124813.8114.3117.6971,98572,67071,27971,864
 4146813.8113.3116.6972,32673,01671,57572,163
 51661013.7113.3116.6972,82373,52072,00672,599
 61881013.7112.3115.6973,00673,70772,16672,762
 72081213.3112.3115.6973,34274,04972,45973,060
 82281412.7412.3115.6973,53274,24272,62673,229
 924101412.7411.3114.6973,58474,29872,67573,280
Group 1082613.9813.3118.6970,79371,46570,25270,826
II 11102814.3113.3118.6971,47672,15570,84071,420
 121221014.1113.3118.6971,98572,67071,27971,864
 131441013.7114.3117.6972,48773,17871,71472,303
 141641213.9812.3117.6972,82573,52272,00772,600
 151861213.9811.3116.6973,00773,70872,16772,764
 162061413.6011.3116.6973,34474,05172,46173,061
 172261613.0611.3116.6973,53174,24272,62573,229
 182481613.0610.3115.6973,58474,29872,67473,280


Section Properties
Beam Type 3 -- 8" Web

Section Area = 459.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 17.49in
\, I_{nontransformed} = 72,106in4
Depth= 39in
Strand Size= 0.60in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184413.4914.4917.5175,94076,59875,39475,957
I 2104614.1614.4917.5176,64277,30775,99976,567
 3124813.9914.4917.5177,16677,83776,45177,023
 4146813.9913.4916.5177,52078,19676,75877,334
 51661013.8913.4916.5178,03478,71677,20377,783
 61881013.8912.4915.5178,22978,91477,37377,956
 72081213.4912.4915.5178,58079,27077,67878,265
 82281412.9212.4915.5178,78179,47577,85578,445
 924101412.9211.4914.5178,84379,54077,91178,504
Group 1082614.1613.4918.5175,94176,59975,39575,958
II 11102814.4913.4918.5176,64177,30675,99876,566
 121221014.2913.4918.5177,16677,83776,45177,023
 131441013.8914.4917.5177,68478,36176,89977,476
 141641214.1612.4917.5178,03678,71877,20477,785
 151861214.1611.4916.5178,23078,91677,37477,957
 162061413.7811.4916.5178,58279,27377,68078,267
 172261613.2411.4916.5178,78079,47577,85478,444
 182481613.2410.4915.5178,84279,54077,91178,503


Section Properties
Beam Type 4 -- 6" Web

Section Area = 428.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 19.54in
\, I_{nontransformed} = 92,450in4
Depth= 45in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184415.5416.5421.4697,72398,69196,97297,800
I 2104616.2116.5421.4698,62399,60297,74898,583
 3124816.0416.5421.4699,318100,30598,34799,189
 4146816.0415.5420.4699,818100,81298,78099,627
 51661015.9415.5420.46100,497101,50199,369100,223
 61881015.9414.5419.46100,808101,81899,640100,499
 72081215.5414.5419.46101,297102,314100,066100,930
 82281414.9714.5419.46101,611102,634100,341101,210
 92481615.2912.5419.46101,761102,789100,475101,347
 1026101615.2911.5418.46101,762102,794100,480101,356
 1128101815.329.5418.46101,633102,667100,372101,250
Group 1282616.2115.5422.4697,72498,69296,97397,801
II 13102816.5415.5422.4698,62299,60197,74798,582
 14124816.0416.5421.4699,318100,30598,34799,189
 151441015.9416.5421.46100,005101,00198,94199,790
 161641216.2114.5421.46100,499101,50399,370100,224
 171661015.9415.5420.46100,497101,50199,369100,223
 181861216.2113.5420.46100,810101,81999,641100,500
 192061415.8313.5420.46101,300102,317100,068100,932
 202261615.2913.5420.46101,610102,633100,340101,209
 212461815.3211.5420.46101,762102,790100,476101,349
 222662015.149.5420.46101,762102,794100,480101,356
 232681815.3210.5419.46101,764102,796100,482101,357
 242862214.817.5420.46101,629102,663100,369101,246
 252882015.148.5419.46101,631102,666100,371101,248
 263082214.816.5419.46101,381102,417100,158101,037
 273282414.374.5419.46101,033102,06999,860100,739


Section Properties
Beam Type 4 -- 7" Web

Section Area = 473.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 19.82in
\, I_{nontransformed} = 100,400in4
Depth= 45in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184415.8216.8221.18105,729106,673104,971105,778
I 2104616.4916.8221.18106,661107,614105,773106,587
 3124816.3216.8221.18107,384108,345106,396107,216
 4146816.3215.8220.18107,908108,876106,850107,675
 51661016.2215.8220.18108,617109,593107,464108,295
 61881016.2214.8219.18108,950109,931107,753108,589
 72081215.8214.8219.18109,464110,453108,201109,041
 82281415.2514.8219.18109,801110,795108,495109,340
 92481615.5712.8219.18109,968110,967108,644109,492
 1026101615.5711.8218.18109,984110,986108,661109,512
 1128101815.609.8218.18109,864110,869108,562109,415
Group 1282616.4915.8222.18105,730106,674104,971105,779
II 13102816.8215.8222.18106,660107,613105,772106,586
 14124816.3216.8221.18107,384108,345106,396107,216
 151441016.2216.8221.18108,100109,069107,015107,841
 161641216.4914.8221.18108,619109,595107,465108,296
 171661016.2215.8220.18108,617109,593107,464108,295
 181861216.4913.8220.18108,951109,933107,755108,590
 192061416.1113.8220.18109,467110,456108,203109,044
 202261615.5713.8220.18109,800110,794108,484109,339
 212461815.6011.8220.18109,970110,969108,645109,494
 222662015.429.8220.18109,984110,986108,661109,512
 232681815.6010.8219.18109,985110,988108,663109,514
 242862215.097.8220.18109,860110,865108,559109,411
 252882015.428.8219.18109,862110,867108,561109,413
 263082215.096.8219.18109,618110,624108,353109,207
 273282414.654.8219.18109,271110,278108,056108,910


Section Properties
Beam Type 4 -- 8" Web

Section Area = 518.9in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 20.06in
\, I_{nontransformed} = 108,288in4
Depth= 45in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


Cont.         Iinitial Ifinal
Span #THSe1e2e3A1 Bars
2-#5
A1 Bars
2-#6
A1 Bars
2-#5
A1 Bars
2-#6
Group 184416.0617.0620.94113,668114,591112,902113,692
I 2104616.7317.0620.94114,627115,559113,727114,523
 3124816.5617.0620.94115,375116,314114,372115,174
 4146816.5616.0619.94115,921116,866114,844115,651
 51661016.4616.0619.94116,655117,608115,480116,291
 61881016.4615.0618.94117,007117,965115,786116,601
 72081216.0615.0618.94117,544118,509116,252117,073
 82281415.4915.0618.94117,900118,870116,563117,387
 92481615.8113.0618.94118,084119,058119,725117,553
 1026101615.8112.0617.94118,112119,089116,754117,584
 1128101815.8410.0617.94118,001118,981116,662117,494
Group 1282616.7316.0621.94113,669114,592112,903113,693
II 13102817.0616.0621.94114,626115,558113,726114,522
 14124816.5617.0620.94115,375116,314114,372115,174
 151441016.4617.0620.94116,116117,062115,012115,819
 161641216.7315.0620.94116,657117,610115,481116,293
 171661016.4616.0619.94116,655117,608115,480116,291
 181861216.7314.0619.94117,009117,967115,787116,603
 192061416.3514.0619.94117,547118,512116,255117,075
 202261615.8114.0619.94117,899118,869116,562117,387
 212461815.8412.0619.94118,085119,059116,727117,554
 222662015.6610.0619.94118,112119,089116,754117,584
 232681815.8411.0618.94118,113119,091116,755117,585
 242862215.338.0619.94117,997118,977116,659117,490
 252882015.669.0618.94117,999118,979116,661117,493
 263082215.337.0618.94117,760118,742116,458117,291
 273282414.895.0618.94117,415118,397116,163116,996


Section Properties
Beam Type 6 -- 6.5" Web

Section Area = 643.6in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 25.92in
\, I_{nontransformed} = 235,735in4
Depth= 54in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


        IinitialIfinal
 #THSe1e2e3A1 Bars
2-#6
A1 Bars
2-#6
Group 11441023.5222.9223.08251,047248,880
I 21641223.2522.9223.08252,425250,070
 31861223.2521.9222.08253,525251,022
 42061423.0621.9222.08254,886252,199
 52261622.9221.9222.08256,238253,370
 62481622.9220.9221.08257,053254,081
 72681822.5920.9221.08258,130255,017
 82882022.3220.9221.08259,191255,940
 930102022.3219.9220.08259,751256,433
 1032102222.1019.9220.08260,803257,350
 1134102421.7519.9220.08261,604258,052
 1236102621.4619.9220.08262,412258,760
 1338122621.4618.9219.08262,739259,053


Section Properties
Beam Type 6 -- 7.5" Web

Section Area = 697.6in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 26.00in
\, I_{nontransformed} = 248,915in4
Depth= 54in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


        IinitialIfinal
 #THSe1e2e3A1 Bars
2-#6
A1 Bars
2-#6
Group 11441023.6023.0023.00264,293262,115
I 21641223.3323.0023.00265,686263,318
 31861223.3322.0022.00266,801264,281
 42061423.1422.0022.00268,178265,473
 52261623.0022.0022.00269,548266,658
 62481623.0021.0021.00270,378267,381
 72681822.6721.0021.00271,472268,330
 82882022.4021.0021.00272,551269,269
 930102022.4020.0020.00273,125269,772
 1032102222.1820.0020.00274,195270,705
 1134102421.8320.0020.00275,014271,420
 1236102621.5420.0020.00275,839272,143
 1338122621.5419.0019.00276,180272,447


Section Properties
Beam Type 6 -- 8.5" Web

Section Area = 751.6in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 26.07in
\, I_{nontransformed} = 262,087in4
Depth= 54in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


        IinitialIfinal
 #THSe1e2e3A1 Bars
2-#6
A1 Bars
2-#6
Group 11441023.6723.0722.93277,522275,336
I 21641223.4023.0722.93278,930276,549
 31861223.4022.0721.93280,057277,523
 42061423.2122.0721.93281,449278,727
 52261623.0722.0721.93282,834279,925
 62481623.0721.0720.93283,678280,658
 72681822.7421.0720.93284,786281,620
 82882022.4721.0720.93285,881282,571
 930102022.4720.0719.93286,468283,085
 1032102222.2520.0719.93287,554284,030
 1134102421.9020.0719.93288,388284,758
 1236102621.6120.0719.93289,228285,493
 1338122621.6119.0718.93289,581285,807

Section Properties
Beam Type 7 -- 6" Web
Bulb-Tee Girder

Section Area = 787.4in2  
NOTE:#=strand pattern number
 T=total number of strands
 H=number of harped strands
 S=number of straight strands
Section \, Y_b = 37.58in
\, I_{nontransformed} = 571,047in4
Depth= 72.5in
Strand Size= 0.6in
\, f'_{ci} = 5ksi
\, f'_c = 7ksi


Cont.        IinitialIfinal
Span #THSe1e2e3A1 Bars
4-#6
A1 Bars
4-#6
Group 11441035.5834.5829.92609,994604,448
I 21641235.2534.5829.92613,316607,307
 31861235.2533.5828.92616,196609,790
 42061435.0133.5828.92619,469612,612
 52261634.8333.5828.92622,719615,417
 62481634.8332.5827.92625,140617,512
 72681834.6932.5827.92628,347620,286
 82882034.5832.5827.92631,536623,046
 930102034.5831.5826.92633,518624,769
 1032102234.3131.5826.92636,280627,166
 1134102434.0831.5826.92639,012629,539
 1236102633.8931.5826.92641,737631,909
 1338102833.5831.5826.92644,052633,926
 1440122833.5830.5825.92645,607635,289

751.22.3.6 Girder Reinforcement

751.22.3.6.1 Reinforcing Steel Details

Bar Reinforcing Steel Details for MoDOT Standard Girders
See Bridge Standard Drawings for details not shown below.
  TABLE OF DIMENSIONS BY GIRDER TYPE
  TYPE 2 TYPE 3 TYPE 4 TYPE 6 TYPE 7
WEB6"7"8"6"7"8"6"7"8"6½"7½"8½"6"
"A"5½"5½"5½"5½"5½"5½"5½"5½"5½"8¾"8¾"8¾"10"
"B"4"4"4"4"4"4"4"4"4"4"4"4"4"
"C"6"6"6"6"6"6"6"6"6"7"7"7"4½"
"D"3¼"3¼"3¼"5⅛"5⅛"5⅛"6¼"6¼"6¼"4⅛"4⅛"4⅛"4⅛"
"E"13"14"15"13"14"15"13"14"15"18"19"20"20"
"F"2"2"2"2"2"2"2"2"2"3"3"3"7¾"
"G"11"12"13"11"12"13"11"12"13"22"23"24"2'-10"
"H"2'-6"2'-6"2'-6"3'-1"3'-1"3'-1"3'-7"3'-7"3'-7"4'-4"4'-4"4'-4"5'-10½"
"I" 3'-0½"3'-0½"3'-0½"3'-7½"3'-7½"3'-7½"4'-1½"4'-1½"4'-1½"4'-10½"4'-10½"4'-10½"6'-5"


Note: Dimensions shown above are out to out.


  TOTAL BAR LENGTH BY GIRDER TYPE
  TYPE 2 TYPE 3 TYPE 4 TYPE 6 TYPE 7
WEB6"7"8"6"7"8"6"7"8"6½"7½"8½"6"
#4-B14'-1"4'-1"4'-1"4'-8"4'-8"4'-8"5'-2"5'-2"5'-2"5'-11"5'-11"5'-11"7'-8"
#5-B14'-1"4'-1"4'-1"4'-8"4'-8"4'-8"5'-2"5'-2"5'-2"5'-11"5'-11"5'-11"7'-7"
#6-B13'-11"3'-11"3'-11"4'-6"4'-6"4'-6"5'-0"5'-0"5'-0"5'-9"5'-9"5'-9"7'-6"
#6-B23'-5"3'-5"3'-5"4'-0"4'-0"4'-0"4'-6"4'-6"4'-6"5'-3"5'-3"5'-3"6'-11"
#4-C113"14"15"13"14"15"13"14"15"2'-2"2'-3"2'-4"3'-5"
#4-D12'-3"2'-4"2'-5"2'-5"2'-6"2'-7"2'-6"2'-7"2'-8"3'-0"3'-1"3'-2"3'-1"


Note: For girders that have excessive haunch or girder steps, create new B1 and C1 bars and adjust heights in one-inch increments to ensure at least 2 inches of embedment into slab.


C1 BAR

(Girders Type 2-6)

C1 BAR

(Girder Type 7)

  B1 and B2 Bar Image:751.22_Section_Thru_Girder_Type_7.gif
Image:751.22_Section_Thru_Girder_2-6.gif
D1 BAR
SECTION THRU GIRDER

(Typical for MoDOT standard girder Type 2-6)

  SECTION THRU GIRDER

(MoDOT standard girder Type 7)

Welded Wire Reinforcing Steel Details for NU Standard Girders

See Bridge Standard Drawings for details. For girders that have excessive haunch or girder steps, create new WWR and adjust heights in one inch increments to ensure at least 2 inches of embedment into slab. Length of WWR sections should be based on shear and confinement requirements before adjusting height to avoid multiple short sections.

Alternate Bar Reinforcing Steel Details for NU Standard Girders

Alternate bar reinforcing steel details shall be provided for all NU girders for all spans.

See Bridge Standard Drawings for details. For girders that have excessive haunch or girder steps, create new B1 bars and adjust heights in one inch increments to ensure at least 2 inches of embedment into slab.

751.22.3.6.2 Shear Reinforcement

The following criteria are preferred by girder manufacturers and reinforcement suppliers. If the design requires a deviation from the preferred criteria then feasibility should be verified with a manufacturer.

MoDOT Standard Girders and NU Standard Girders with Alternate Bar Reinforcing Steel

  • B1 bars shall be either #4 or #5 epoxy-coated bars with #4 bars preferred to allow permissible alternate bar shape. Using #6 B1 bars does not provide one inch clearance when center strands are spaced one inch off centerline of girder between hold down devices because of bend radius of the #6 bars.
  • The same shear reinforcement bar size shall be used in a girder. Using the same shear reinforcement bar size for all of the spans is preferred but not required for girders of different spans lengths.
  • 6” is the preferred minimum spacing.
  • 5” spacing may be used for first set if required.
  • 21” is the maximum spacing for #4 bars.
  • 24” is the maximum spacing for #5 bars.
  • 3” increment spacing shall be used (i.e. 6”, 9”, 12”, 15”, 18”, 21” and 24”) except when less than 6” spacing is required for the first set. In this case, 6” or 9” shall be used for the next set of B1 bars.
  • Four or less spacing changes are preferred for spans up to 100 feet.
  • Six spacing changes may be used for spans greater than 100 feet.
  • Using the same spacing scenario (i.e. sets of B1 bars at 6”, 12” and 18” spacing) for all of spans is preferred but not required for girders of different span lengths.

NU Standard Girders with Welded Wire Reinforcing Steel

  • WWR shall be uncoated and shall use either D18, D20, D22 or D31 vertical wire sizes.
  • The same shear reinforcement wire size shall be used in a girder. Using the same shear reinforcement wire size for all of the spans is preferred but not required for girders of different spans lengths.
  • 4” is the preferred minimum spacing.
  • 2” or 3” spacing (maximum eight spaces) may be used for WWR1 if required.
  • 20” is the maximum spacing for the D18, D20 and D22 wire sizes.
  • 24” is the maximum spacing for the D31 wire size.
  • 4” increment spacing shall be used (i.e. 4”, 8”, 12”, 16”, 20” and 24”) except when the required spacing of WWR1 is less than 4”. In this case, 4” or 8” shall be used for WWR2.
  • Three or less spacing changes (WWR pieces) are preferred for spans less than 100 feet.
  • An additional spacing change (WWR piece) may be used when the spacing of WWR1 is less than 4” or in spans greater than 100 feet.
  • Using the same spacing scenario (i.e. S1=4”, S2=12” and S3=20”) for all of the spans is preferred but not required for girders of different span lengths.

751.22.3.6.3 Anchorage Zone Reinforcement

The following details meet the criteria for anchorage zone reinforcement for pretensioned girders in EPG 751.22.2.4 for all MoDOT and NU standard girder shapes.


MoDOT Standard Girder End Section Reinforcement


NU Standard Girder End Section Reinforcement

Typical end section reinforcement shall be all welded wire reinforcement (WWR) or all deformed bars. If additional reinforcement is required with WWR, the following options shall be considered.

   Option 1 (Preferred) Option 2    (Use for heavier reinforcement)
Option 1 (Preferred) Option 2
(Use for heavier reinforcement)

Minimum spacing of reinforcing bars shall be in accordance with LRFD 5.10.3.1.2.

Consideration shall be given to spacing reinforcing bars 1” clear from welded studs on bearing plates (not shown).


Bearing Plate Anchor Studs


The standard ½" bearing plate will be anchored with four ½" x 4" studs for MoDOT shapes and eight ½” x 5” studs for NU shapes.

If required, increase the number of ½" studs and space between open B2 bars.


The minimum ¼" fillet weld between the ½" bearing plate and 1½" sole plate is adequate for all cases.

LFD Seismic Design

Studs shall be designed to meet the criteria of 2002 AASHTO 17th Edition Division I-A in Seismic Performance Category C or D.

Stud capacity is determined as follows for:

Stud Cap. = (n)(As)(0.4Fy)(1.5)
Where:
N = number of studs
As = area of stud
Fy = yield strength of stud (50 ksi)
0.4Fy = Allowable Shear in Pins AASHTO Table 10.32.1A
1.5 = seismic overload factor

If required, increase the number of 1/2” studs to six and space between open B2 bars or WWF. If this is still not adequate, 5/8” studs may be used. The following table may be used as a guide for upper limits of dead load reactions:

No. of Studs Stud Dia.Max Allowable D.L Reaction (kips)
A = 0.30 A = 0.36
4 1/2” 78 65
6 1/2” 117 98
4 5/8” 122 102
6 5/8” 184 153
8 1/2” 156 130
10 1/2” 195 163
8 5/8” 244 204
10 5/8” 306 255

751.22.3.7 Bent-up Strands

Bent-up strands for positive moment connection

Tables below show the number of bent-up strands for closed and open diaphragms (with a continuous superstructure), respectively. Provide a minimum number of bent-up strands as shown in tables at the bottom of girder ends. These bent-up strands shall be adequate to resist a positive moment over the bents.


*     Varies
* *   #5 bars typical at each layer of bent-up strands.
* * *   Use 3’-0” projection for NU Girders.
(1)   #5-strand tie bars normal to girder.


WEB
THICKNESS
(INCHES)
NUMBER OF BOTTOM STRANDS FOR POSITIVE MOMENT
CONNECTION (C)
BEAM TYPE 2 BEAM TYPE 3BEAM TYPE 4BEAM TYPE 6BEAM TYPE 7
(BULB-TEE)
6668---12
6-1/2---------10---
7(A)688------
7-1/2(B)---------12---
8(A)6810------
8-1/2(B)---------12---
(A) Modified Beam Type 2, 3 or 4.
(B) Modified Beam Type 6.
(C) If available. Otherwise, bend all bottom strands.


NUMBER OF BOTTOM STRANDS FOR POSITIVE MOMENT CONNECTION (C)
NU 35 10
NU 43 10
NU 53 10
NU 63 12
NU 70 12

751.22.3.8 Camber, Haunching and Girder Steps

Camber

Compute theoretical camber of girder at 90 days and show on the plan as a “Theoretical camber of girder after erection (Estimated at 90 days)". Compute theoretical camber of girder at 7 days and show on the plan as a “Theoretical camber of girder after strand release (Estimated at 7 days)". Camber shall be reported to the nearest 1/8 inch.

Sample detail:

Show conversion factors for girder camber with camber diagram as per EPG 751.50 H2c6.1.

Note: The example shows Dimension A as greater than Dimension C. When Dimension A is less than Dimension C, modify detail to show this correctly keeping definitions of Dimensions A and C the same. MS Cells are given for each case.

Haunching

Haunching for a P/S I-girder bridge is the distance between the top of the girder and the bottom of the slab.

Haunching shall be computed at quarter (1/4) points for bridges with spans less than 75 feet, and at tenth (1/10) points for span 75 feet and longer. Haunching shall be reported to the nearest 1/8 inch. A typical theoretical slab haunching diagram as shown below shall be provided on all P/S I-girder bridges.

For full depth cast-in-place decks, a minimum haunch of 1 in. at the centerline of girder and 1/2 in. at the edge of the girder flange shall be provided to allow for construction tolerances and normal concrete variations. For NU and MoDOT Bulb-Tee standard girders, the minimum haunch may need to be increased. See the Structural Project Manager or Structural Liaison Engineer for full depth cast-in-place decks.

For the same reasons the following minimum haunch shall be provided for precast prestressed panel deck slabs:

1 1/8” for MoDOT standard girders Type 2, 3 and 4
1 1/4” for MoDOT standard girder Type 6
1 1/2” for MoDOT standard girders Type 7 and 8 (bulb-tee) and NU standard girders

A minimum of 1 in. shall be made available below the precast prestressed panels to allow for adequate flow of concrete below the panel. This is accomplished by specifying the placement of 1 in. minimum joint filler thickness under all panels.

The following maximum haunch at the centerline of the girder is allowed when prestressed panels are used:

2 1/2" for MoDOT standard girders Type 2, 3 and 4
4 1/2” for MoDOT standard girders Type 6, 7 and 8 and NU standard girders

A maximum haunch of 3 1/2 in. is allowed for all girders when only the cast-in-place option is used.

The maximum joint filler thickness to be used for supporting panels shall be 2 inches for MoDOT standard girders Type 2, 3 and 4 or 4 inches for MoDOT standard girders Type 6, 7 and 8 and NU standard girders; the remaining haunch thickness will be addressed by varying the slab thickness.

Sample detail:


Girder Haunch Reinforcement

Hairpin reinforcement may be required in accordance with EPG 751.10.1.14 Girder Haunch Reinforcement.

Girder Steps

Steps shall be provided on prestressed girders with precast prestressed panels as shown below to keep the haunch from exceeding 2 inches for MoDOT standard girders Type 2, 3 and 4 or exceeding 4 inches for MoDOT standard girders Type 6, 7 and 8 and NU standard girders. The minimum step height shall be 1/2 inch with 1/2 inch increments with no limit of the number of steps.

Image:751.22_Girder_Steps.gif
PART ELEVATION OF GIRDER SECTION A-A


Girder Top Flange Step Example


Top of Girder

Tops of girders, for bridges with a superelevation of more than 2 percent, shall be sloped across the top flange to match the superelevation as shown below. The minimum thickness of the top flange shall be the standard flange thickness and the overall height at the minimum point shall be the standard girder height.

NU and MoDOT Bulb-Tee standard girders with top flanges exceeding a 4 percent cross-slope may experience sweep after form removal because of the unsymmetrical section and a resulting imbalanced prestressed load. It is recommended that the flange thickness be increased to only half of that required (but less than or equal to 4 percent cross-slope) and the height difference mitigated using thicker joint filler on the high side. If thicker joint filler cannot be fully used to compensate for the height difference, the extra load of a thicker slab must be accounted for in the design of the girders.

Image:751.22_Superelevation_Slope.gif


Top Flange Slope with Superelevation

751.22.3.9 Open Intermediate Bent Diaphragms

(Expansion Intermediate Bent with Continuous Slab)

Dimensions:

PART ELEVATION
FOR BULB-TEE GIRDERS
PART ELEVATION



PART PLAN



 
PART SECTION A-A
* A sloped diaphragm allows clearance for the future placement of jacks needed to replace bearings.

** For Bulb-Tee Girder, spacings less than 8'-8" dimensions A, B & C may have to be modified.

*** Make sure the diaphragm is wide enough to provide enough cover for the Coil Tie Rods.

**** Not given on plans.

GIRDER
TYPE
DIMENSIONS
A B C
TYPE 2
2'-8"
12"15"13"
TYPE 3
3'-3"
17"15"19"
TYPE 4
3'-9"
19"18"21"
TYPE 6
4'-6"
2'-3"21"2'-1"
BULB-TEE
6'-0½ *
3'-0"2'-6½"2'-9"
NU 35 **** 18” 14”
NU 43 **** 18” 19”
NU 53 **** 20” 22”
NU 63 **** 2’-0” 2’-0”
NU 70 **** 2’-4” 2’-7”


(Expansion Intermediate Bent with Continuous Slab)

Coil Tie Rod:

PART ELEVATION


* 6" (Min.) shall be used for all I-Girders including Bulb-Tee and NU Girders.


Image:751.22_Open_Int_Bent_Diaphragms_Coil_Tie_Rod_Part_Section_AA_Details.gif
PART SECTION A-ADETAILS OF COIL TIE RODS
IN BULB-TEE GIRDERS


(Expansion Intermediate Bent with Continuous Slab)

Reinforcement:


Image:751.22_Open_Int_Bent_Diaphragms_Reinf_Part_Elevations.gif
PART ELEVATION
FOR BULB-TEE GIRDERS
PART ELEVATION


Image:751.22_Open_Int_Bent_Diaphragms_Reinf_Part_Plan.gif


PART PLAN


(1) For Bulb-Tee Girders, the first #6 Bar shall be placed 10" from the centerline of Web (Top Flange will prevent some Bars from extending into the Slab). Image:751.22_Open_Int_Bent_Diaphragms_Reinf_Part_Section.gif
 
 
(*) See Section "A" for the placement of reinforcement.

(**) Use the same clearance as longitudinal slab steel.
(***) #5 Bars for each layer of bent up strands.

PART SECTION A-A

751.22.3.10 Closed Intermediate Bent Diaphragms

(Fixed Intermediate Bents with Continuous Slab)
Dimensions:


Image:751.22_Closed_Int_Bent_Diaphragms_Dim_Part_Elevations.gif
PART ELEVATION FOR
BULB-TEE GIRDERS
PART ELEVATION


Image:751.22_Closed_Int_Bent_Diaphragms_Dim_Part_Plan.gif
PART PLAN


Image:751.22_Closed_Int_Bent_Diaphragms_Dim_Part_Plan_Showing_Jt_Filler.gif
PART PLAN
(Showing Joint Filler)


Image:751.22_Closed_Int_Bent_Diaphragms_Detail_of_Key.gif (*) Make flush with Bent Caps less than 3'-0" wide. For Bent Caps 3'-0" and over, make Diaphragms 2'-6" wide unless skew requires wider Diaphragm to accommodate Coil Ties.
 
(**) For tapered bearings or for bearings with different thickness use the following note: "Fill area under girders with Joint Filler."


(Expansion Intermediate Bents with Continuous Slab)
Dimensions:


Image:751.22_Closed_Int_Bent_Expansion_Diaphragms_Dim_Part_Elevations.gif
PART ELEVATION FOR
BULB-TEE GIRDERS
PART ELEVATION
PART ELEVATION FOR NU GIRDERS
PART ELEVATION FOR NU GIRDERS
Image:751.22_Closed_Int_Bent_Expansion_Diaphragms_Dim_Part_Plan.gif
PART PLAN
Image:751.22_Closed_Int_Bent_Expansion_Diaphragms_Dim_Part_Longitudinal_Elevation.gif (*) Make flush with Bent Caps less than 3'-0" wide. For Bent Caps 3'-0" and over, make Diaphragm 2'-6" wide unless skew requires wider Diaphragm to accommodate Coil Ties.

(**) Use Shear Blocks when Bent Cap steps down in one direction or when there are less than two steps in each direction with maximum step height less than 1 1/2" each.

Shear Blocks shall be detailed parallel to the centerline of roadway and shall be designed to resist 0.20 times the tributary weight where tributary weight is defined as the total bent dead load reaction. See this section for shear block design method.

PART LONGITUDINAL ELEVATION  


(Fixed and Expansion Intermediate Bents with Continuous Slab)
Reinforcement (Square Structure):


Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Square_Structures_Part_Elevations.gif


PART ELEVATION FOR
BULB-TEE GIRDERS
PART ELEVATION
PART ELEVATION FOR NU GIRDERS
PART ELEVATION FOR NU GIRDERS


(1) For Bulb-Tee Girders, the #6 Bar shall be a min. of 15" from centerline of Girder and will not extend past the bottom of the top flange.

(2)For Bulb-Tee Girders, use 3-#4 Bars in each Diaphragm face.



(*) #5 Bars for each layer of bent up strands.

(**) Use the same clearance as the longitudinal slab steel.

(***) By design, Min. #6 Dowel bars @ 12" cts. (Typ.) (Fixed bent only).

Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Square_Structures_Part_Plan.gif


Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Square_Structures_Part_Elevation_AA.gif Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Square_Structures_Section_Thru_Diaphragm.gif
PART ELEVATION A-A SECTION THRU DIAPHRAGM


(Fixed and Expansion Intermediate Bents with Continuous Slab)
Reinforcement (Skewed Structure):


Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Skewed_Structures_Part_Elevations.gif
PART ELEVATION FOR
BULB-TEE GIRDERS
PART ELEVATION


(1) For Bulb-Tee Girders, the #6 Bar shall be a min. of 15" from centerline of Girder and will not extend past the bottom of the top flange.

(2)For Bulb-Tee Girders, use 3-#4 Bars in each Diaphragm face.



(*) #5 Bars for each layer of bent up strands.

(**) Omit leg on outside of exterior girder.

(***) By design, Min. #6 Dowel bars @ 12" cts. (Typ.) (Fixed bent only).

Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Skewed_Structures_Part_Plan.gif


Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Skewed_Structures_Thru_25_Deg.gif Image:751.22_Closed_Int_Bent_Fixed_and_Expansion_Diaphragms_Reinf_Skewed_Structures_Over_25_Deg.gif
SKEWS THRU 25 DEG. SKEWS OVER 25 DEG.


(Change in Girder Height at Fixed Bents)
General:

Change girder heights within a continuous girder series only when specified on Design Layout or by Structural Project Manager.

Girder heights can only be changed at fixed bents for continuous series.

See EPG 751.11.3.6 Girder/Beam Chairs for additional girder chair details.

(Change in Girder Height at Fixed Bents) Reinforcement:

Image:751.22_Closed_Int_Bent_Diaphragms_Reinf_Change_in_Height_at_Fixed_Bents.gif
PART ELEVATION



Image:751.22_Closed_Int_Bent_Diaphragms_Reinf_Change_in_Height_at_Fixed_Bents_Part_Plan.gif
PART PLAN


(*) By design, min. #6 dowel bars @ 12" cts. (Typ.)

(1) At each layer of bent strands.

(2) For bulb-tee girders, use 3-#4 bars in each diaphragm face.

(3) 3" min. when using beam step.

(4) By design, min. #6 @ 12" cts. dowel bars (Typ.)


Image:751.22_Closed_Int_Bent_Diaphragms_Reinf_Change_in_Height_at_Fixed_Bents_Part_Section_AA_Thru_Diaphragm.gif
PART SECTION A-A THRU DIAPHRAGM


Note: Girder heights can change a maximum of one girder type.

(1) For bulb-tee girders, use 3-#4 bars in each diaphragm face.


(Change in Girder Height at Fixed Bents)
Edge Distance Details:


PART PLAN SKEWED STRUCTURES
NOTE:Field bending may be required for #4 and #6 H Bars
in skewed structures near short exterior girder.
* 5” (Min.) for MoDOT Standard P/S Girders and
3 ½” (Min.) for NU Standard P/S Girders (Typ.)
** 8 ½” (Min.) for MoDOT Standard P/S Girders and
7” (Min.) for NU Standard P/S Girders (Typ.)


Image:751.22_Closed_Int_Bent_Diaphragms_Edge_Distance_Change_in_Height_at_Fixed_Bents_Part_Plan_Square.gif
PART PLAN SQUARED STRUCTURES

(1) When beam width is controlled by girder chair clearance, make diaphragm flush with beam cap.


3/4" Chamfer and 1/2" Joint Filler

Image:751.22_Closed_Int_Bent_Diaphragms_Chamfer_&_Joint_Filler_Section.gif
SECTION THRU
INTERMEDIATE DIAPHRAGMS


Image:751.22_Closed_Int_Bent_Diaphragms_Chamfer_&_Joint_Filler_Detail.gif
DETAIL "A"

751.22.3.11 Non-integral End Bent Diaphragms

(End Diaphragm with no Expansion Devices)
Dimensions:

PART ELEVATION FOR
BULB-TEE GIRDERS
PART ELEVATION NEAR END BENT



PART PLAN NEAR END BENT



 
PART SECTION A-A
* A sloped diaphragm allows clearance for the future placement of jacks needed to replace bearings.
 

** For Bulb-Tee Girder, spacings less than 8'-8" dimensions A, B & C may have to be modified.
 
*** Make sure the diaphragm is wide enough to provide cover for the coil tie rods.
 
**** Not given on plans.

GIRDER
TYPE
DIMENSIONS
A B C
TYPE 2
2'-8"
12"15"13"
TYPE 3
3'-3"
17"15"19"
TYPE 4
3'-9"
19"18"21"
TYPE 6
4'-6"
2'-3"21"2'-1"
BULB-TEE
6'-0½ *
3'-0"2'-6½"2'-9"
NU 35 **** 18” 14”
NU 43 **** 18” 19”
NU 53 **** 20” 22”
NU 63 **** 2’-0” 2’-0”
NU 70 **** 2’-4” 2’-7”


(End Diaphragm with no Expansion Devices)
Coil Tie Rods:



PART ELEVATION NEAR END BENT


NOTE:For location of the Coil Tie Rods in a plan view, see Coil Ties.
 * 6" (Min.) shall be used for all I-Girders including Bulb-Tee and NU Girders.


Image:751.22_Non_Integral_End_Bent_Diaphragms_No_Exp_Device_Coil_Tie_Rods_Part_Section.gif Image:751.22_Non_Integral_End_Bent_Diaphragms_No_Exp_Device_Coil_Tie_Rods_Details.gif
 EXTERIOR GIRDERSINTERIOR GIRDERS
PART SECTION A-ADETAILS OF COIL TIE RODS
IN BULB-TEE GIRDERS



(End Diaphragm with no Expansion Devices)
Reinforcement:


Image:751.22_Non_Integral_End_Bent_Diaphragms_No_Exp_Device_Reinforcement_Part_Elevation.gif


PART ELEVATION
NEAR END BENT FOR
BULB-TEE GIRDERS
PART ELEVATION NEAR END BENT


Image:751.22_Non_Integral_End_Bent_Diaphragms_No_Exp_Device_Reinforcement_Part_Plan.gif
PART PLAN NEAR END BENT


 (1) For Bulb-Tee Girders, the first #6 Bar shall be placed 10" from the centerline of Web (Top Flange will prevent some Bars from extending into the Slab).
Image:751.22_Non_Integral_End_Bent_Diaphragms_No_Exp_Device_Reinforcement_Part_Section.gif  
NOTE: Bars across end of girders to be continuous.
(*) Use the same clearance as longitudinal slab steel.
(**) Show this dimension Bridge Plan Sheets.
PART SECTION A-A


(End Diaphragm with Expansion Devices)
Dimensions:


PART ELEVATION
FOR BULB-TEE GIRDERS
PART ELEVATION NEAR END BENT
PART PLAN NEAR END BENT

 
PART SECTION A-A
* For Bulb-Tee Girder, spacings less than 8'-8" dimensions A, B & C may have to be modified.
GIRDER
TYPE
DIMENSIONS
A B C
TYPE 2
2'-8"
12"15"13"
TYPE 3
3'-3"
17"15"19"
TYPE 4
3'-9"
19"18"21"
TYPE 6
4'-6"
2'-3"21"2'-1"
BULB-TEE
6'-0½ *
3'-0"2'-6½"2'-9"
NU 35 **** 18” 14”
NU 43 **** 18” 19”
NU 53 **** 20” 22”
NU 63 **** 2’-0” 2’-0”
NU 70 **** 2’-4” 2’-7”
** A sloped diaphragm allows clearance for the future placement of jacks needed to replace bearings.
*** Make sure the diaphragm is wide enough to provide cover for the coil tie rods.
*** Not given on plans.


(End Diaphragm with Expansion Devices)
Coil Tie Rods:


PART ELEVATION NEAR END BENT


NOTE:For location of the Coil Tie Rods in a plan view, see Coil Ties.
 * 6" (Min.) shall be used for all I-Girders including Bulb-Tee and NU Girders.


Image:751.22_Non_Integral_End_Bent_Diaphragms_with_Exp_Device_Coil_Tie_Rods_Part_Section_AA.gif Image:751.22_Non_Integral_End_Bent_Diaphragms_with_Exp_Device_Coil_Tie_Rods_Details.gif
 EXTERIOR GIRDERSINTERIOR GIRDERS
PART SECTION A-ADETAILS OF COIL TIE RODS
IN BULB-TEE GIRDERS



(End Diaphragm with Expansion Devices)
Reinforcement:


Image:751.22_Non_Integral_End_Bent_Diaphragms_with_Exp_Device_Reinforcement_Part_Elevation.gif
PART ELEVATION
NEAR END BENT FOR
BULB-TEE GIRDERS
PART ELEVATION NEAR END BENT
Image:751.22_Non_Integral_End_Bent_Diaphragms_with_Exp_Device_Reinforcement_Part_Plan.gif
PART PLAN NEAR END BENT


 (1) For Bulb-Tee Girders, the first #6 Bar shall be placed 10" from the centerline of Web (Top Flange will prevent some Bars from extending into the Slab).
Image:751.22_Non_Integral_End_Bent_Diaphragms_with_Exp_Device_Reinforcement_Part_Section.gif  
NOTE: Epoxy Coat all Reinforcing Steel in the End of Diaphragms.

NOTE: Bars across end of girders to be continuous.

(*) Use the same clearance as longitudinal slab steel.
(**) Show this dimension Bridge Plan Sheets.
PART SECTION A-A

751.22.3.12 Non-integral Intermediate Bent Diaphragms

(End Diaphragms with Expansion Device)
Dimensions:


NOTE: Slope at top of Beam Cap and Protective
Coating to be used on Structures with Expansion
Devices.
PART ELEVATION FOR
BULB-TEE GIRDERS
PART ELEVATION NEAR INT. BENT



PART PLAN NEAR INT. BENT



 
PART SECTION A-A
* A sloped diaphragm allows clearance for the future placement of jacks needed to replace bearings.
GIRDER
TYPE
DIMENSIONS
A B C
TYPE 2
2'-8"
12"15"13"
TYPE 3
3'-3"
17"15"19"
TYPE 4
3'-9"
19"18"21"
TYPE 6
4'-6"
2'-3"21"2'-1"
BULB-TEE
6'-0½ *
3'-0"2'-6½"2'-9"
NU 35 **** 18” 14”
NU 43 **** 18” 19”
NU 53 **** 20” 22”
NU 63 **** 2’-0” 2’-0”
NU 70 **** 2’-4” 2’-7”
** For Bulb-Tee Girder, spacings less than 8'-8" dimensions A, B & C may have to be modified.
*** Make sure the diaphragm is wide enough to provide enough cover for the Coil Tie Rods.
**** Not given on plans.


(End Diaphragms with Expansion Device)
Coil Tie Rods:



PART ELEVATION NEAR INT. BENT


NOTE:For location of the Coil Tie Rods in a plan view, see Coil Ties.
 * 6" (Min.) shall be used for all I-Girders including Bulb-Tee and NU Girders.


Image:751.22 Non Integral Intermediate Bent Diaphragm with Exp Device Coil Tie Rod Part Section.gif Image:751.22_Non_Integral_Intermediate_Bent_Diaphragm_with_Exp_Device_Coil_Tie_Rod_Details.gif
 EXTERIOR GIRDERSINTERIOR GIRDERS
PART SECTION A-ADETAILS OF COIL TIE RODS
IN BULB-TEE GIRDERS


(End Diaphragms with Expansion Device)
Reinforcement:


Image:751.22_Non_Integral_Intermediate_Bent_Diaphragm_with_Exp_Device_Reinf_Elevations.gif
PART ELEVATION
NEAR INT. BENT FOR
BULB-TEE GIRDERS
PART ELEVATION NEAR INT. BENT
Note: Slope at top of beam cap and protective coating to be used on structures with expansion devices.


(1) For Bulb-Tee Girders, the first #6 Bar shall be placed 10" from the centerline of Web (Top Flange will
prevent some Bars from extending into the Slab).
Image:751.22_Non_Integral_Intermediate_Bent_Diaphragm_with_Exp_Device_Reinf_Part_Plan.gif
PART PLAN NEAR INT. BENT


Image:751.22_Non_Integral_Intermediate_Bent_Diaphragm_with_Exp_Device_Reinf_Part_Section.gif Image:751.22_Non_Integral_Intermediate_Bent_Diaphragm_with_Exp_Device_Reinf_Detail.gif
PART SECTION A-A DETAIL "A"
(*) See Detail "A" for the placement of reinforcement.

(**) Use the same clearance as longitudinal slab steel.

NOTE: Epoxy coat all reinforcing steel in the end diaphragms.


(End Diaphragm with Finger Plate Expansion Device)
Diaphragm Reinforcements:


CLOSED DIAPHRAGM:

(NOTE: Use only when expansion device connects prestress girder series and steel girder series.)
Image:751.22_Non_Integral_Intermediate_Bent_Diaphragm_with_Finger_Plate_Exp_Device_Reinf_Closed_Diaphragm.gif


NOTE: See preceding sheets for bar spacing and detail not shown.

A protective coating shall be applied to concrete surface exposed to drainage from roadway. Indicate surface to be coated on plans. Epoxy coat all reinforcing steel in the end diaphragms.

  (2) For Bulb-Tee Girders use 3-#4 Bars in each face.


OPEN DIAPHRAGM

Image:751.22_Non_Integral_Intermediate_Bent_Diaphragm_with_Finger_Plate_Exp_Device_Reinf_Open_Diaphragm.gif
(*)Use only on Type 6 Girder
(**)12" for #4 Bars
14" for #6 Bars
(Shown on Plans)
 

(1) Use the same clearance as longitudinal slab steel.

751.22.3.13 Intermediate Diaphragms

Use steel intermediate diaphragm for prestressed spans over 50 feet except for NU 35 and NU 43 girders.


Bridge Standard Drawings
Steel Intermediate Diaphragms


All Girders

Use straight diaphragm normal to girders for skews thru 20°.

Use stepped diaphragm for skews over 20°.

Bulb-Tee Girders

Bulb-Tee spans of 90 ft. or less require one intermediate diaphragm per span.

Bulb-Tee spans of over 90 ft. require two intermediate diaphragms per span (spaced equally as allowed by clearance to harped strands). Maximum spacing is 50 ft.

NU 35 and NU 43 Girders

Permanent intermediate diaphragms are not required for NU 35 and NU 43 standard girders. Temporary intermediate diaphragms/bracing are required for construction of the bridge deck. See EPG 751.50 Note H2c2.2.

751.22.3.14 Coil Ties


PART ELEVATION FOR
BULB-TEE GIRDERS
PART ELEVATION


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PART PLAN
(SQUARE)

* 4" Min. (Typ.) (Do not show Dim. on Plans)


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PART PLAN
(SKEWED TO 20 DEG.)


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PART PLAN
(SKEWED OVER 20 DEG.)


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EXTERIOR GIRDER AT END BENT


(1)3" For Beam Type 2
5" For Beam Type 3, 4 & 6
 
NOTE:See previous page for location of Coil Tie Rods on Bulb-Tee girders.

751.22.3.15 Dowel Bars


PART ELEVATION
(FIXED BENT)
SECTION A-A


Dowel bars shall be used for all fixed intermediate bents under prestressed superstructures. Generally, shear resistance from shear key is not considered for typical bridges in seismic performance Category A.


Dowel bars shall be determined by design. (Minimum #6 Bars @ 12" Cts.) For shear stress, fv, computation, see EPG 751.9.3.1.2 Dowel Bars.
fv\,\phiv ● Fvn
Where,
\,\phiv = Resistance factor
fv = Shear stress (ksi)
Fvn = Nominal shear resistance of dowel bar (ksi)

751.22.3.16 Vent Holes

Note: Use vent holes on all stream crossing structures.


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PART ELEVATION OF GIRDER PART SECTION NEAR VENT HOLE


Note: Place vent holes at or near upgrade of 1/3 point of girders and clear
reinforcing steel or strands by 1-1/2" minimum and steel intermediate
diaphragms bolt connection by 6" minimum.

751.22.3.17 Shear Blocks

A minimum of two Shear Blocks 12" wide x (1) high by width of diaphragm, will be detailed at effective locations on open diaphragm bent caps when adequate structural restraint cannot be provided for with anchor bolts.

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ELEVATION VIEW


(1) Height of shear block shall extend a minimum of 1" above the top pf the sole plate.


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ELEVATION VIEW


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PLAN VIEW


Note:
Shear blocks shall be used at bents with open diaphragms when anchor bolts can not be designed to resist earthquake loading.
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PLAN VIEW OF BEAM CAP
EXPANSION BENTS WITH OPEN DIAPHRAGMS


Note:
For Expansion Bents with open diaphragms, the steps or Shear Block (if applicable) should be normal to the length of cap.


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PLAN VIEW OF BEAM CAP
EXPANSION BENTS WITH CLOSED DIAPHRAGMS


Note:
For Closed Diaphragm Expansion Bents, the steps or haunches shall be detailed parallel to the centerline of roadway.

For Integral End Bents the steps may be skewed due to stirrups being placed parallel to centerline of roadway.

Shear Blocks for Expansion Bents with Closed Diaphragms shall be detailed parallel to the centerline of roadway. Shear Blocks used in conjunction with sole plates and anchor bolts shall be detailed parallel to the edge of sole plate.

751.22.3.18 Miscellaneous

Dimensional Tolerances

I-Girders, Solid Slab Beams, Voided Slab Beams, Box Beams, Double-Tee Girders, Deck Panels and Miscellaneous Prestress Units, see Sec 1029


Expansion Device Support Slots


Used with preformed compression joint seal, flat plate, strip seal or finger plate expansion devices.


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PART PLAN OF P/S CONC. I-GIRDER @ EXP. DEVICE END


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PART ELEVATION OF P/S CONC. I-GIRDER @ EXP. DEVICE END


(*) Show these dimensions on the P/S concrete girder sheet.


Anchor Bolts
Simple Spans


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PART ELEVATION
Note:

It is permissible for the reinforcing bars and or the strands to come in contact with the materials used in forming A.B. holes.

If A.B. holes are formed with galvanized sheet metal, the forms may be left in place.

Hole (1-1/2"ø) to be grouted with expansive type mortar meeting the requirements of Sec 1066.

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