Difference between revisions of "751.12 Barriers, Railings, Curbs and Fences"

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m (minor clarification, per Bridge)
m (→‎751.12.1.2.1 Slip Forming: Per BR, replaced guidance about determining C bars lengths with actual length of C bars.)
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== 751.12.1 Standard Safety Barrier Bridge Curbs ==
+
To be found eligible for Federal-aid funding, new roadside safety devices should meet the crash test and evaluation criteria contained in the American Association of State Highway and Transportation Officials’ (AASHTO) Manual for Assessing Safety Hardware (MASH).  Since neither FHWA nor AASHTO has a system in place to approve roadside devices, the responsibility is left with the States.  In response, MoDOT has developed a MASH Implementation process. All roadside devices that are submitted after November 1, 2019, will be reviewed by the MASH Team for approval to use on Missouri roadways. Prior to November 1, 2019 roadside devices were considered using the criterion set forth in NCHRP Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features”.  While MASH requirements are only applicable to the NHS, the following guidelines are recommended for all bridges.
  
 +
AASHTO LRFD uses the term “railing” to refer to all types of bridge traffic barrier systems used on bridges. MoDOT uses the term “barrier” for solid concrete bridge railing (single-faced on the edge of roadway and dual-faced medians) and the term “railing” for barrier systems consisting of a rail(s) and supports.
  
=== 751.12.1.1 Standard Safety Barrier Curbs used in Missouri ===
+
==751.12.1 Concrete Barriers==
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
Type D barrier replaced Type B barrier (previously safety barrier curb) as the standard railing for bridges awarded after December 31, 2019. Similarly, Type C barrier replaced Type A barrier (previously median barrier curb).  Types H and G shall be used respectively for situations where Types D and C is considered impractical.
|-
+
[[image:751.12.1.jpg|center|600px]]
|colspan="2"|[[Image:751.12 barrier curb - NJ Shape.gif]]
+
Single sloped barriers have been shown to reduce vehicle climb and increase vehicle stability during redirections when compared to New Jersey shaped barriers.  See the following sections for more details on standard barriers. Details for Type G have not been developed, but that does not prevent its use if need dictates.
|-
 
|Type A<br/>Test Level TL-4
 
|Type B<br/>Test Level TL-4
 
|-
 
!colspan="2"|NJ Shape
 
|-
 
|colspan="2"| &nbsp;
 
|-
 
|colspan="2"|[[Image:751.12 barrier curb - type c & d.gif]]
 
|-
 
|Type C<br/>Test Level TL-5
 
|Type D<br/>Test Level TL-5
 
|}
 
  
 +
Concrete barriers were approved for TL-3 or TL-4 test levels in accordance with the MASH 2016 standards.  The required MASH 2016 test level for bridges on the National Highway System (NHS) is TL-3, but the expectation is that the TL-4 requirement will be mandated in the next publication.
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:left"
+
Test level TL-3 is defined by AASHTO as being “generally acceptable for a wide range of high-speed arterial highways with very low mixtures of heavy vehicles and with favorable site conditions.
|-
 
!Note:
 
|For Type F (Temporary Barrier Curb), refer to Missouri Standard Plans 617.20.
 
|-
 
| &nbsp;
 
|For Thrie Beam Rails, see Widening & Repair information.
 
|-
 
| &nbsp;
 
|See Structural Project Manager before using Type C or D barriers.
 
|}
 
 
 
== 751.12.2 Safety Barrier Bridge Curbs (NJ Shape) ==
 
 
 
  
=== 751.12.2.1 General Design ===
+
Test level TL-4 is defined by AASHTO as being “generally acceptable for the majority of applications on high-speed highways, freeways, expressways, and interstate highways with a mixture of trucks and heavy vehicles”.
  
New safety barrier curbs "shall be shown to be structurally and geometrically crashworthy".  Therefore, the shape of the safety barrier curb is selected based on crash-tested, or equivalent crash-tested geometry. 
+
===751.12.1.1 Material Properties===
 
+
{| style="margin: 1em auto 1em auto"
The safety barrier curb used on new bridges shall be the 16” New Jersey (MO) safety shape barrier curb which has been crash-tested and FHWA approved as meeting test level TL-4.
 
 
 
Test level TL-4 shall be used for safety barrier curb design.  TL-4 is defined by AASHTO as being “generally acceptable for the majority of applications on high-speed highways, freeways, expressways, and interstate highways with a mixture of trucks and heavy vehicles”.
 
 
 
 
 
<center>[[Image:751.12 safety barrier curb dimensions.gif]]</center>
 
<center>* Use Rustication on Highway Grade Seperations only</center>
 
<center>'''Safety Barrier Curb Dimensions'''</center>
 
 
 
 
 
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
 
|+'''Material Properties'''
 
!align="left"|Concrete
 
| &nbsp;
 
|-
 
|align="right"|Unit weight of reinforced concrete,
 
|<math>\, \gamma_c</math> = 150 <math>\,lb/ft^3</math>
 
|-
 
|align="right"|for modulus of elasticity,
 
|<math>\, \gamma_c</math> = 145 <math>\,lb/ft^3</math>
 
|-
 
!align="left"|Safety Barrier Curbs
 
| &nbsp;
 
|-
 
|align="left"|Safety Barrier Curbs shall consist of:
 
| &nbsp;
 
 
|-
 
|-
|align="right"|Class B-1 Concrete
+
!Class B-1 Concrete!! !! Epoxy Coated Reinforcing Steel
| <math>\, f'_c</math> = 4.0 ksi
 
 
|-
 
|-
| &nbsp;
+
|Unit weight (reinforced), wc = 0.150 kcf||width="15px| ||Yield strength, fy = 60.0 ksi
|<math>\, n</math> = 8
 
 
|-
 
|-
!align="left"|Median Barrier Curbs
+
|Compressive strength, f’c = 4.0 ksi|| ||Modulus of elasticity, Es = 29,000 ksi
| &nbsp;
 
 
|-
 
|-
|align="left"|Median Barrier Curbs shall consist of:
+
|Modular ratio, n = 8|| ||
| &nbsp;
 
 
|-
 
|-
|align="right"|Class B-1 Concrete
+
|Modulus of elasticity, Ec = 3644 ksi || ||
| <math>\, f'_c</math> = 4.0 ksi
 
|-
 
| &nbsp;
 
|<math>\, n</math> = 8
 
|-
 
!align="left"|Reinforcing steel
 
| &nbsp;
 
|-
 
|align="right"|Minimum yield strength,
 
|<math>\, f_y</math> = 60.0 ksi
 
|-
 
|align="right"|Steel modulus of elasticity
 
|<math>\, E_s</math> = 29000 ksi
 
 
|}
 
|}
  
=== 751.12.2.2 Standard Reinforcement Details ===
+
===751.12.1.2 General Details===
 +
Regardless of type of barrier shown the following sections are applicable for all concrete barrier types.
  
{|border="0" cellpadding="10" cellspacing="1" align="center" style="text-align:center"
+
Top of barrier shall be built parallel to grade with barrier joints (except at end bents) normal to grade.
  
|[[Image:751.12 r-bar no wearing surface.gif]]
+
All exposed edges of barrier shall have either a 1/2-inch radius or a 3/8-inch bevel, unless otherwise noted.  
|[[Image:751.12 r1-bar no wearing surface.gif]]
 
|[[Image:751.12 r2-bar no wearing surface.gif]]
 
|-
 
!rowspan="2" valign="top"|R-Bar<br/>Required for Slip Form Option
 
!R1-Bar<br/>Shape 19
 
!R2-Bar<br/>Shape 15
 
|-
 
!colspan="2"|R1 & R2-Bars permissible<br/>only when Slip Forming<br/>not allowed (*)
 
|-
 
|colspan="3"|[[Image:751.12 16in standard safety barrier curb no wearing surface.gif]]
 
|-
 
!colspan="3"|16" Safety Barrier Curb
 
|}
 
<blockquote>
 
(*) The single R bar adds to the rigidity of the reinforcement during construction and it is believed to help prevent cracking. The single bar also appears to assist maintaining uniform
 
reinforcement cover.
 
</blockquote>
 
  
 +
====751.12.1.2.1 Slip Forming====
 +
Conventional or slip forming may be used except for situations where slip forming is considered impractical.
  
 +
See barrier elevation sheets of the [http://www.modot.org/business/standard_drawings2/Barrier_curbs_new_title_block.htm barrier standard drawings] for the required details.
  
{|border="0" cellpadding="2" cellspacing="1" align="center" style="text-align:center"
+
Slip forming is impractical for prestressed double-tee bridges.
!colspan="4"|Reinforcement (No Wearing Surface)
 
|-
 
|rowspan="3"|[[Image:751.12 r-bar no wearing surface.gif]]
 
|rowspan="3"|[[Image:751.12 16in safety barrier curb no wearing surface.gif]]
 
|[[Image:751.12 r3-bar no wearing surface.gif]]
 
|[[Image:751.12 r4-bar no wearing surface.gif]]
 
|-
 
!#5-R3<br/>Shape 19
 
!#5-R4<br/>Shape 27 (*)
 
|-
 
|colspan="2"|[[Image:751.12 r-bar permissible shape no wearing surface.gif]]
 
|-
 
!valign="top"|R-Bar
 
!valign="top"|16" Safety Barrier Curb
 
!colspan="2"|R-Bar Permissible<br/>Alternate Shape (**)
 
|-
 
|colspan="4"| &nbsp;
 
|-
 
!colspan="4"|Reinforcement (1 3/4" Wearing Surface)
 
|-
 
|rowspan="3"|[[Image:751.12 r-bar 1.75 in wearing surface.gif]]
 
|rowspan="3"|[[Image:751.12 16in safety barrier curb 1.75 in wearing surface.gif]]
 
|[[Image:751.12 r3-bar 1.75 in wearing surface.gif]]
 
|[[Image:751.12 r4-bar 1.75 in wearing surface.gif]]
 
|-
 
!#5-R3<br/>Shape 19
 
!#5-R4<br/>Shape 27
 
|-
 
|colspan="2"|[[Image:751.12 r-bar permissible shape 1.75 in wearing surface.gif]]
 
|-
 
!valign="top"|R-Bar
 
!valign="top"|16" Safety Barrier Curb
 
!colspan="2"|R-Bar Permissible<br/>Alternate Shape (**)
 
|-
 
|colspan="4"| &nbsp;
 
|-
 
!colspan="4"|Reinforcement (2 1/4" Wearing Surface)
 
|-
 
|rowspan="3"|[[Image:751.12 r-bar 2.25 in wearing surface.gif]]
 
|rowspan="3"|[[Image:751.12 16in safety barrier curb 2.25 in wearing surface.gif]]
 
|[[Image:751.12 r3-bar 2.25 in wearing surface.gif]]
 
|[[Image:751.12 r4-bar 2.25 in wearing surface.gif]]
 
|-
 
!#5-R3<br/>Shape 19
 
!#5-R4<br/>Shape 27
 
|-
 
|colspan="2"|[[Image:751.12 r-bar permissible shape 2.25 in wearing surface.gif]]
 
|-
 
!valign="top"|R-Bar
 
!valign="top"|16" Safety Barrier Curb
 
!colspan="2"|R-Bar Permissible<br/>Alternate Shape (**)
 
|-
 
|colspan="4" align="left"|(*) Increase leg for latex or low slump concrete wearing surface.
 
|-
 
|colspan="4" align="left"|(**) The R3 bar and #5 bottom transverse slab bar in cantilever (P/S panels only) combination may be<br/>furnished as one bar as shown, at the contractor's option.
 
|}
 
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
 
|Note:
 
|align="left"|Use same grade reinforcing steel in Barrier Curb as in slab. Splice length for #5 bars in Barrier Curb = 35".
 
|-
 
| &nbsp;
 
|align="left"|Dimensions shown are also typical for structures with latex or low slump concrete (except as indicated).
 
|}
 
 
 
=== 751.12.2.3 End Bent Reinforcement ===
 
  
{|border="0" cellpadding="1" cellspacing="0" align="center" style="text-align:center"
+
'''Cross Bracing C Bars'''
|+'''Non-Integral End Bents'''
 
|colspan="2"|[[Image:751.12 non-integral end bent end elevation of barrier curb.gif]]
 
|colspan="2"|[[Image:751.12 non-integral end bent elevation of barrier curb.gif]]
 
|-
 
!colspan="2"|End Elevation
 
!colspan="2"|Elevation of Barrier Curb
 
|-
 
|colspan="2"|[[Image:751.12 non-integral end bent section a-a.gif]]
 
|[[Image:751.12 non-integral end bent section b-b.gif]]
 
|[[Image:751.12 non-integral end bent section c-c.gif]]
 
|-
 
!colspan="2"|Section A-A
 
!Section B-B
 
!Section C-C
 
|-
 
|align="right"|*
 
|colspan="3" align="left"|Spaced with #5-K4 bars.
 
|-
 
|align="right"|**
 
|colspan="3" align="left"|Fit bar to follow transition face of curb.
 
|}
 
  
 +
Slip forming requires two No. 5 cross bracing C bars located each side of all joints and at barrier ends.
  
{|border="0" cellpadding="1" cellspacing="0" align="center" style="text-align:center"
+
List C bars in the Bill of Reinforcing Steel and note that bars are for the slip-formed option only.
|colspan="5"|All bars are epoxy coated.
 
|-
 
|colspan="5"|All bars are stirrup bends except for K4, K9, K10 & K11.
 
|-
 
|[[Image:751.12 non-integral end bent k1.gif]]
 
|[[Image:751.12 non-integral end bent k2.gif]]
 
|[[Image:751.12 non-integral end bent k3.gif]]
 
|[[Image:751.12 non-integral end bent k4.gif]]
 
|[[Image:751.12 non-integral end bent k5.gif]]
 
|-
 
!#5-K1<br/>Shape 19
 
!#5-K2<br/>Shape 14
 
!#5-K3<br/>Shape 27
 
!#5-K4<br/>Shape 7
 
!#5-K5<br/>Shape 25
 
|-
 
|[[Image:751.12 non-integral end bent k6.gif]]
 
|[[Image:751.12 non-integral end bent k7.gif]]
 
|[[Image:751.12 non-integral end bent k8.gif]]
 
|colspan="2"|[[Image:751.12 non-integral end bent k9.gif]]
 
|-
 
!#5-K6<br/>Shape 25
 
!#5-K7<br/>Shape 25
 
!#5-K8<br/>Shape 25
 
!colspan="2"|#5-K9<br/>Shape 20
 
|-
 
|colspan="2"|[[Image:751.12 non-integral end bent k10.gif]]
 
|colspan="2"|[[Image:751.12 non-integral end bent k11.gif]]
 
|rowspan="2" align="left"|(*) Increase leg for slab<br/>thickness greater than<br/>8 1/2".
 
|-
 
!colspan="2"|#4-K10<br/>Shape 20
 
!colspan="2"|#5-K11<br/>Shape 8
 
|}
 
  
 +
For barrier segments on top of the bridge deck, use 12-foot C1 bars.
  
 +
For barrier segments on top of the end bent wings (Type B, D or H):
 +
:For segment lengths less than 14'-4", use C2 bars with the following lengths:
  
<div id="integral end bent barrier curb"></div>
+
::{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
{|border="0" cellpadding="1" cellspacing="0" align="center" style="text-align:center"
+
|+  
|+'''Integral End Bents'''
+
! style="background:#BEBEBE" rowspan="2"| !! colspan="6" |Barrier Segment Length
|colspan="2"|[[Image:751.12 integral end bent end elevation of barrier curb.gif]]
 
|colspan="2"|[[Image:751.12 integral end bent elevation of barrier curb.gif]]
 
|-
 
!colspan="2"|End Elevation
 
!colspan="2"|Elevation of Barrier Curb
 
|-
 
|colspan="2"|[[Image:751.12 integral end bent section a-a.gif]]
 
|[[Image:751.12 integral end bent section b-b.gif]]
 
|[[Image:751.12 integral end bent section c-c.gif]]
 
|-
 
!colspan="2"|Section A-A
 
!Section B-B
 
!Section C-C
 
|-
 
|align="right"|*
 
|colspan="3" align="left"|Spaced with #5-K4 bars.
 
 
|-
 
|-
|align="right"|**
+
!8' to < 9'!! 9' to < 10'!! 10' to < 11'!! 11' to < 12'!! 12' to < 13'!! 13' to <14'-4"
|colspan="3" align="left"|Fit bar to follow transition face of curb.
 
 
|-
 
|-
|align="right" valign="top"|***
+
|'''Bar Length''' ||5'-9" ||6'-9" ||7'-9" ||8'-9" ||9'-9" ||10'-6"
|colspan="3" align="left"|On skewed structures, if end K3 bar does not meet the Min. 1 1/2" clearance<br/>from front face of diaphragm, a K12 bar may be substituted.
 
 
|}
 
|}
  
 +
:For segment lengths 14'-4" to 18 feet, use 12-foot C1 bars.
 +
:For section greater than 18 feet, use two sets of 8-foot C2 bars.
  
{|border="0" cellpadding="1" cellspacing="2" align="center" style="text-align:center"
+
'''Textured Fiberglass Bars'''
|colspan="5"|All bars are epoxy coated.
 
|-
 
|colspan="5"|All bars are stirrup bends except for K4, K9, K10 & K11.
 
|-
 
|[[Image:751.12 integral end bent k1.gif]]
 
|[[Image:751.12 integral end bent k2.gif]]
 
|[[Image:751.12 integral end bent k3.gif]]
 
|[[Image:751.12 integral end bent k4.gif]]
 
|[[Image:751.12 integral end bent k5.gif]]
 
|-
 
!#5-K1<br/>Shape 19
 
!#5-K2<br/>Shape 14
 
!#5-K3<br/>Shape 27
 
!#5-K4<br/>Shape 7
 
!#5-K5<br/>Shape 25
 
|-
 
|[[Image:751.12 integral end bent k6.gif]]
 
|[[Image:751.12 integral end bent k7.gif]]
 
|[[Image:751.12 integral end bent k8.gif]]
 
|colspan="2"|[[Image:751.12 integral end bent k9.gif]]
 
|-
 
!#5-K6<br/>Shape 25
 
!#5-K7<br/>Shape 25
 
!#5-K8<br/>Shape 25
 
!colspan="2"|#5-K9<br/>Shape 20
 
|-
 
|colspan="2"|[[Image:751.12 integral end bent k10.gif]]
 
|colspan="2"|[[Image:751.12 integral end bent k11.gif]]
 
|[[Image:751.12 integral end bent k12.gif]]
 
|-
 
!colspan="2"|#4-K10<br/>Shape 20
 
!colspan="2"|#5-K11<br/>Shape 8
 
!#5-K12<br/>Shape 27
 
|}
 
  
 +
Slip forming requires three four-feet long No. 4 textured fiberglass bars centered at each joint.
  
 +
====751.12.1.2.2 Joints====
 +
See barrier elevation sheets of the [http://www.modot.org/business/standard_drawings2/Barrier_curbs_new_title_block.htm barrier standard drawings] for the required details.
  
 +
One-fourth-inch joints are located in the barrier at locations of negative moments to prevent cracking in the barrier. Barrier joints may be formed using ¼-inch joint filler in accordance with Sec 1057 or saw cut and seal with silicone joint sealant in accordance with Sec 717. Saw cuts joints may be used with the conventional forming option.
  
<div id="barrier curb details-semi deep"></div>
+
Joints are required when decks are continuous over intermediate bents for both continuous and simple span structures. These joints are also required at the front face of integral end bents. For placement of barrier joints at integral end bents see integral end bent details.
{|border="0" cellpadding="1" cellspacing="0" align="center" style="text-align:center"
+
[[image:751.12.1.2.2.1.jpg|center|550px]]  
|+'''Semi-Deep Abutments'''
 
|colspan="4"|[[Image:751.12 semi-deep abutment elevation of barrier curb.gif]]
 
|-
 
!colspan="4"|Elevation of Barrier Curb
 
|-
 
|width="35%"|[[Image:751.12 semi-deep abutment end elevation of barrier curb.gif]]
 
|width="35%"|[[Image:751.12 semi-deep abutment section a-a.gif]]
 
|colspan="2"|[[Image:751.12 semi-deep abutment section b-b.gif]]
 
|-
 
!End Elevation
 
!Section A-A
 
!colspan="2"|Section B-B
 
|-
 
  
|rowspan="2"|[[Image:751.12 semi-deep abutment section c-c.gif]]
+
Additional joints at 12-foot spacing from joint at intermediate bents may be required based on span lengths. The following details provide guidance on locating flexural joints near intermediate bents. This spacing will allow the full yield-line failure pattern to develop for Type D barrier. For simplicity, the 12-foot spacing shall also be used for all other concrete barrier types.
|rowspan="2"|[[Image:751.12 semi-deep abutment section d-d.gif]]
+
[[image:751.12.1.2.2.2.jpg|center|600px]]
|align="right" width="5%"|*
 
|colspan="4" align="left" |Spaced with #5-K4 bars.
 
|-
 
|align="right" |**
 
|colspan="4" align="left" |Fit bar to follow transition face of curb.
 
|-
 
!Section C-C
 
!Section D-D
 
| &nbsp;
 
| &nbsp;
 
|}
 
  
 +
====751.12.1.2.3 Plastic Waterstops====
 +
See barrier elevation sheets of the [http://www.modot.org/business/standard_drawings2/Barrier_curbs_new_title_block.htm barrier standard drawings] for the required details.
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
Plastic waterstops are typically located inside formed joints to eliminate water seepage problems on grade separations. They shall be excluded over railroads and county roads and are only required on the lower side of superelevated decks.
|colspan="5"|All bars are epoxy coated.
 
|-
 
|colspan="5"|All bars are stirrup bends except for K4, K9, K10 & K11.
 
|-
 
|[[Image:751.12 semi-deep abutment k1.gif]]
 
|[[Image:751.12 semi-deep abutment k2.gif]]
 
|[[Image:751.12 semi-deep abutment k3.gif]]
 
|[[Image:751.12 semi-deep abutment k4.gif]]
 
|[[Image:751.12 semi-deep abutment k5.gif]]
 
|-
 
!#5-K1<br/>Shape 19
 
!#5-K2<br/>Shape 14
 
!#5-K3<br/>Shape 27
 
!#5-K4<br/>Shape 7
 
!#5-K5<br/>Shape 25
 
|-
 
|[[Image:751.12 semi-deep abutment k6.gif]]
 
|[[Image:751.12 semi-deep abutment k7.gif]]
 
|[[Image:751.12 semi-deep abutment k8.gif]]
 
|colspan="2"|[[Image:751.12 semi-deep abutment k9.gif]]
 
|-
 
!#5-K6<br/>Shape 25
 
!#5-K7<br/>Shape 25
 
!#5-K8<br/>Shape 25
 
!colspan="2"|#5-K9<br/>Shape 20
 
|-
 
|colspan="2"|[[Image:751.12 semi-deep abutment k10.gif]]
 
|colspan="2"|[[Image:751.12 semi-deep abutment k11.gif]]
 
|[[Image:751.12 semi-deep abutment k12.gif]]
 
|-
 
!colspan="2"|#4-K10<br/>Shape 20
 
!colspan="2"|#5-K11<br/>Shape 8
 
!#5-K12<br/>Shape 27
 
|}
 
  
 +
====751.12.1.2.4 Guardrail Attachment====
 +
See barrier at end bents sheets of the [http://www.modot.org/business/standard_drawings2/Barrier_curbs_new_title_block.htm barrier standard drawings] for the required details.
 +
[[image:751.12.2.6.jpg|center|325px]]
  
 +
====751.12.1.2.5 Superelevation====
 +
Superelevated slope, S.E., is in decimal format for the follow calculation, i.e. use 0.04 for 4.0%.
 +
[[image:751.12.2.5.1.jpg|center|650px]]
 +
[[image:751.12.2.5.2.jpg|center|670px]]
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
====751.12.1.2.6 Detached Wing Walls====
|+'''Continuous Concrete Slab'''
+
If the detached wing wall has more than one section, see the Structural Project Manager for possible additional joints in the barrier (between sections).  
|colspan="2"|[[Image:751.12 cont conc slab end bent end elevation of barrier curb.gif]]
 
|colspan="2"|[[Image:751.12 cont conc slab end bent elevation of barrier curb.gif]]
 
|-
 
!colspan="2"|End Elevation
 
!colspan="2"|Elevation of Barrier Curb
 
|-
 
|colspan="2"|[[Image:751.12 cont conc slab end bent section a-a.gif]]
 
|[[Image:751.12 cont conc slab end bent section b-b.gif]]
 
|[[Image:751.12 cont conc slab end bent section c-c.gif]]
 
|-
 
!colspan="2"|Section A-A
 
!Section B-B
 
!Section C-C
 
|-
 
|align="right"|*
 
|colspan="3" align="left"|Spaced with #5-K4 bars.
 
|-
 
|align="right"|**
 
|colspan="3" align="left"|Fit bar to follow transition face of curb.
 
|}
 
  
 +
The following details are for illustration purposes only:
 +
[[image:751.12.2.6 end bents.jpg|center|550px]]
  
{|border="0" cellpadding="1" cellspacing="2" align="center" style="text-align:center"
+
====751.12.1.2.7 Details of Mounting Light Poles on Safety Barrier Curbs====
|colspan="5"|All bars are epoxy coated.
+
[[image:751.12.2.7.1 2020.jpg|center|550px]]
|-
+
[[image:751.12.2.7.2 2020.jpg|center|625px]]
|colspan="5"|All bars are stirrup bends except for K4, K9, K10 & K11.
 
|-
 
|[[Image:751.12 cont conc slab end bent k1.gif]]
 
|[[Image:751.12 cont conc slab end bent k2.gif]]
 
|[[Image:751.12 cont conc slab end bent k3.gif]]
 
|[[Image:751.12 cont conc slab end bent k4.gif]]
 
|[[Image:751.12 cont conc slab end bent k5.gif]]
 
|-
 
!#5-K1<br/>Shape 19
 
!#5-K2<br/>Shape 14
 
!#5-K3<br/>Shape 27
 
!#5-K4<br/>Shape 7
 
!#5-K5<br/>Shape 27
 
|-
 
|[[Image:751.12 cont conc slab end bent k6.gif]]
 
|[[Image:751.12 cont conc slab end bent k7.gif]]
 
|[[Image:751.12 cont conc slab end bent k8.gif]]
 
|colspan="2"|[[Image:751.12 cont conc slab end bent k9.gif]]
 
|-
 
!#5-K6<br/>Shape 27
 
!#5-K7<br/>Shape 27
 
!#5-K8<br/>Shape 27
 
!colspan="2"|#5-K9<br/>Shape 20
 
|-
 
|colspan="2"|[[Image:751.12 cont conc slab end bent k10.gif]]
 
|colspan="2"|[[Image:751.12 cont conc slab end bent k11.gif]]
 
|&nbsp;
 
|-
 
!colspan="2"|#4-K10<br/>Shape 20
 
!colspan="2"|#5-K11<br/>Shape 8
 
|&nbsp;
 
|-
 
|align="right" valign="top"|*
 
|colspan="4" align="left" valign="top"|According to the development length allowed with the slab depth used, bar may or may not be hooked.  Development length starts at slab/barrier interface, basic development length for a straight, #5 epoxy coated bar is 18".
 
|-
 
|align="right" valign="top"|**
 
|colspan="4" align="left" valign="top"|Length varies depending on slab depth.  Extend bar to within 1" of construction joint at bottom of slab.
 
|-
 
|align="right" valign="top"|***
 
|colspan="4" align="left" valign="top"|Use Shape 11 or create shape as necessary when development length requires hook.
 
|}
 
  
=== 751.12.2.4 Slip-Form Reinforcement Details ===
+
Anchor bolts and nuts shall be in accordance with ASTM A449. Anchor bolts, nuts and washers shall be galvanized in accordance with AASHTO M 232 (ASTM A153), Class C.  
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
'''Note to Detailer:''' Extend slab transverse steel to edge of slab in blister region often shown with an additional detail with the slab details.
  
|[[Image:751.12 section at end bent (optional slip-form barrier).gif]]
+
'''Note:''' Conduit not shown for clarity.
|-
 
!Section at End Bent (Optional Slip-Form Barrier)
 
|-
 
| &nbsp;
 
|-
 
|[[Image:751.12 section near joint (optional slip-form barrier).gif]]
 
|-
 
!Section Near Joints (Optional Slip-Form Barrier)
 
|-
 
| &nbsp;
 
|-
 
|[[Image:751.12 optional slip-form barrier section a-a.gif]]
 
|-
 
!Section A-A
 
|-
 
|(*) Each side of Joint Location.
 
|}
 
  
'''NOTE TO DETAILER:'''
+
===751.12.1.3 Type D and H (42ʺ and 32ʺ single sloped railing)===
 +
The 42-inch single sloped Type D barrier shall be used for railing on all new or replacement bridge projects except where sight distance is a concern.  Type D meets the height requirements for both MASH TL-4 (36ʺ) and Occupational Safety and Health Administration’s OSHA (42ʺ).  Type D barrier has been reviewed by the Midwest Roadside Safety Facility (MwRSF) and is compliant with MASH 2016 TL-4.  This assessment is applicable for continuous and discontinuous sections of the barrier.  Type D barrier shall be used on all redecks and rehabs where the full length of barrier is being replaced with exceptions for the following: 1) sight distance concerns, 2) rating concerns where the weight of the barrier prohibits its use or causes impractical restrictions or costs for the project. The Type D barrier dimensions shall not be adjusted for inclusion of a wearing surface.
  
Optional Slip-Form Safety Barrier Curb details shall be placed on all jobs (except Prestressed Double-Tee Structures) where applicable.
+
The 32-inch single sloped Type H barrier shall be used for railing, upon approval of the SPM or SLE, on all new or replacement bridge projects where sight distance concerns prohibit the use of Type D.  Type H has the same front face slope as Type DThe minimum height for MASH TL-3 is 30 inches so there are minimal concerns with Type H for future overlays. The TL-3 height requirement has been updated since the release of SEG 20-001. Type H barrier has been reviewed by the Midwest Roadside Safety Facility (MwRSF) and is compliant with MASH 2016 TL-3.  This assessment is applicable for continuous and discontinuous sections of the barrier. When a wearing surface is applied with the newly constructed Type H barrier, a pedestal is recommended to keep the holes for the guardrail attachment in the same location with respect to the top of the barrier.
   
 
Add #5 cross bracing bars for Slip-Form option. Base the length of these bars on the shortest distance between joints throughout the structure. Show the C-Bars in the Bar List and note that these bars are for the Slip-Form option only.
 
  
=== 751.12.2.5 SBC for Wing with Detached Wing Wall ===
+
====751.12.1.3.1 Typical Section====
 +
All values may be used with both 2.0% and 3/16 inch-per-foot cross slopes.
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
See [[#751.12.1.2.5 Superelevation|EPG 751.12.1.2.5 Superelevation]] for adjustment of values for different cross slopes.
 +
[[image:751.12.1.3.1.jpg|center|700px]]
  
|colspan="2"|[[Image:751.12 safety barrier curb on non-integral end bent.gif]]
+
====751.12.1.3.2 Typical Section Reinforcement====
|-
+
The single R bar adds to the rigidity of the reinforcement during construction and it is believed to help prevent cracking. The single bar also appears to assist maintaining uniform reinforcement cover.  
!colspan="2"|SBC on Non-Integral End Bent (*)
 
|-
 
| &nbsp;
 
|-
 
|colspan="2"|[[Image:751.12 safety barrier curb on integral end bent.gif]]
 
|-
 
!colspan="2"|SBC on Integral End Bent (*)
 
|-
 
|align="right"|(*)
 
|align="left"|Detached Wing Wall shown is for illustration purpose only.
 
|-
 
| &nbsp;
 
|align="left"|If the detached wing wall has more than one section, see the Structural Project Manager<br/>for possible additional joints in the safety barrier curb (between sections).
 
|}
 
  
=== 751.12.2.6 Guardrail Attachment Detail ===
+
Splice length for horizontal #5 bars in barrier curb shall be 37 inches.  
  
 +
All bent bars are formed using stirrup bends except for the Type D #5-R1 bars.
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
All values may be used with both 2.0% and 3/16 inch-per-foot cross slopes.
 +
[[image:751.12.1.3.2.jpg|center|750px]]
  
|[[Image:751.12 guard rail attachment detail part elevation a-a.gif]]
+
====751.12.1.3.3 End of Barrier Reinforcement====
|[[Image:751.12 guard rail attachment detail part elevation.gif]]
+
See [http://www.modot.org/business/standard_drawings2/Barrier_curbs_new_title_block.htm barrier standard drawings] for the required details.
|-
+
 
!Part Elevation A-A
+
All bent bars are formed using stirrup bends.
!Part Elevation
 
|-
 
|&nbsp;
 
|[[Image:751.12 guard rail attachment detail part plan.gif]]
 
|-
 
|&nbsp;
 
!Part Plan
 
|-
 
|colspan="2"|[[Image:751.12 guard rail attachment detail auxiliary view.gif]]
 
|-
 
!colspan="2"|Auxiliary View
 
|}
 
  
=== 751.12.2.7 Joint & Rustication Details ===
+
All dimensions shown may be used with both 2.0% and 3/16 inch-per-foot cross slopes.
  
'''Curb Expansion Joints.''' Openings required for expansion shall be provided in the barrier curb in conjunction with deck joints. For details of expansion joints in barrier curb see expansion device details.
+
=====751.12.1.3.3.1 Type D Ending on Integral End Bents=====
 +
Use when distance between upper and lower construction joint in wings is at least 28½ inches.
 +
[[image:751.12.1.3.3.1.1.jpg|center|700px]]
 +
[[image:751.12.1.3.3.1.2.jpg|center|700px]]
  
'''Curb Joints.'''  1/4 in. joints are located in the barrier curb at locations of negative moments to prevent cracking in the barrier curb. These joints are required when decks are continuous over intermediate bents for both continuous and simple span structures. These joints are also required at the front face of integral end bents. For details of 1/4 in. curb joints at integral end bents see integral end bent details.
+
=====751.12.1.3.3.2 Type H Ending on Integral End Bents=====
 +
Use when distance between upper and lower construction joint in wings is at least 28½ inches.
 +
[[image:751.12.1.3.3.2.1.jpg|center|700px]]
 +
[[image:751.12.1.3.3.2.2.jpg|center|700px]]
  
'''Rustication.''' Rustication shall be used on grade separations only. Rustication shall be terminated four feet from the end of the barrier curb.
+
=====751.12.1.3.3.3 Type D Ending on Shallow Integral End Bents=====
 +
Use when distance between upper and lower construction joint in wings is less than 28½ inches.
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
Formulas extend bars to within 1½ʺ of lower construction joint.
  
!colspan="3"|Cast-In-Place Barrier Curbs
+
Use Shape 27 for K3 bar in Barbill program to obtain correct weight and length. Revise Shape 27 on plan sheet to Shape 50 and add shape to bending diagrams.
|-
+
[[image:751.12.1.3.3.3.1.jpg|center|700px]]
|colspan="3"|[[Image:751.12 joint and rustication details plan of curb joints.gif]]
+
[[image:751.12.1.3.3.3.2.jpg|center|680px]]
|-
 
| || || width=400px | &nbsp;&nbsp;&nbsp;Note: Sawcut between spans shall be offset from centerline of intermediate bent to match any existing offset.
 
|-
 
!align="right"|Continuous Structures Part Plan
 
||
 
!&nbsp;&nbsp;&nbsp;Continuous Re-Deck of Simple Span Structures Part Plan
 
|-
 
|colspan="3"| &nbsp;
 
|-
 
|colspan="3"|[[Image:751.12 joint and rustication details all types of cont structure elevation.gif]]
 
|-
 
!colspan="3"| Part Section Showing Placement of Joints
 
|}
 
{|cellspacing="1" align="center"
 
|align="right" valign="top"|*||One space = 1/4 Span to nearest 1 in. increment (Span < 40 ft.)
 
|-
 
| || One space = 10 ft. (Span = 40 ft. to 125 ft.)
 
|-
 
| || Two spaces = 10 ft. (Span > 125 ft.)
 
|}
 
  
 +
=====751.12.1.3.3.4 Type H Ending on Shallow Integral End Bents=====
 +
Use when distance between upper and lower construction joint in wings is less than 28½ inches.
  
 +
Formulas extend bars to within 1½ʺ of lower construction joint.
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
Use Shape 27 for K3 bar in Barbill program to obtain correct weight and length. Revise Shape 27 on plan sheet to Shape 50 and add shape to bending diagrams.
 +
[[image:751.12.1.3.3.4.1.jpg|center|680px]]
 +
[[image:751.12.1.3.3.4.2.jpg|center|700px]]
  
!colspan="2"|Optional Slip-Form Barrier Curbs
+
=====751.12.1.3.3.5 Type D Ending on Non-Integral End Bents=====
|-
+
Use when distance between upper and lower construction joint in wings is at least 28½ inches.
|colspan="2"|[[Image:751.12 joint and rustication details optional slip-form section thru joint and section a-a.gif]]
+
[[image:751.12.1.3.3.5.1.jpg|center|700px]]
|-
+
[[image:751.12.1.3.3.5.2.jpg|center|680px]]
!width="410pt"|Section A-A
 
!width="300pt"|Section Thru Joint
 
|-
 
|colspan="2"|[[Image:751.12 joint and rustication details optional slip-form all types of cont structure elevation.gif]]
 
|-
 
!colspan="2"|Part Section Showing Placement of Joints
 
|}
 
  
{|cellspacing="1" align="center"
+
=====751.12.1.3.3.6 Type H Ending on Non-Integral End Bents=====
|}
+
Use when distance between upper and lower construction joint in wings is at least 28½ inches.
 +
[[image:751.12.1.3.3.6.jpg|center|700px]]
  
 +
=====751.12.1.3.3.7 Type D Ending at End of Slab (Redecks)=====
 +
Splice length of #5 K12 and #5 K13 bars with #5 R-bars shall be 37 inches.
 +
[[image:751.12.1.3.3.7.jpg|center|700px]]
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
=====751.12.1.3.3.8 Type H Ending at End of Slab (Redecks)=====
|-
+
Splice length of #5 K7 bars with #5 R-bars shall be 37 inches.
|colspan="2"|[[Image:751.12 joint and rustication details optional slip-form part plan continuous structures.gif]]
+
[[image:751.12.1.3.3.8.jpg|center|700px]]
|-
 
| || width="300px"|Note: Sawcut between spans shall be offset from centerline of intermediate bent to match any existing offset.
 
|-
 
!Continuous Structures Part Plan
 
!Continuous Re-Deck of Simple Span Structures Part Plan
 
|-
 
| || width="300px"|'''Note:''' Rustication shall be used on grade separations only. Terminate rustication 4 ft. 0 in. from end of wing.
 
|}
 
  
 +
===751.12.1.4 Type B (32ʺ New Jersey Shaped Railing)===
 +
The 32-inch New Jersey shaped railing, previously referred to as safety barrier curb, shall not be used on new construction projects.  This includes redecks and rehabs where the full length of barrier is being replaced. Type B barrier may be replaced in kind where spot work is required (i.e., expansion joint replacements).  For wearing surface projects, where the grade is not being increased more than 2 inches, the existing Type B barrier may be used in place in accordance with [[751.1 Preliminary Design#751.1.3.4 Barrier or Railing Type, Height and Guidelines for Curb Blockouts|EPG 751.1.3.4 Barrier or Railing Type, Height and Guidelines for Curb Blockouts]].
  
 +
=====751.12.1.4.1 Typical Section=====
 +
[[image:751.12.1.4.1.jpg|center|650px]]
 +
See [[#751.12.1.2.5 Superelevation|EPG 751.12.1.2.5 Superelevation]] for adjustment of values for different cross slopes.
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
=====751.12.1.4.2 Typical Section Reinforcement=====
 +
The single R bar adds to the rigidity of the reinforcement during construction and it is believed to help prevent cracking. The single bar also appears to assist maintaining uniform reinforcement cover.
  
|[[Image:751.12 joint and rustication details part section showing rustication details.gif]]
+
Splice length for horizontal #5 bars in barrier curb shall be 37 inches.  
|align="left"|'''Note:''' Rustication to be used on<br/>highway grade separation only.<br/>End rustication 4'-0" from end<br/>of wing.
 
|-
 
!Part Section Showing Rustication Details
 
| &nbsp;
 
|}
 
  
=== 751.12.2.8 Plastic Waterstop ===
+
All bent bars are formed using stirrup bends except for the R1 bars.
 +
[[image:751.12.1.4.2.jpg|center|700px]]
  
To eliminate water seepage problems, use a plastic waterstop, as specified, and in accordance with details shown below.
+
=====751.12.1.4.3 End of Barrier Reinforcement=====
+
See barrier ending on end bents sheets of the [http://www.modot.org/business/standard_drawings2/Barrier_curbs_new_title_block.htm barrier standard drawings] for the required details. The bars shown below are for barrier ending on wing walls; see barrier ending at end of slab sheet of the barrier standard drawings for reinforcement details for barrier ending on slabs.  
Use a plastic waterstop at all safety barrier curb joints on grade separations, except over railroads and county roads.
 
 
Use a plastic waterstop on lower safety barrier curb joint only, for structures with superelevation on grade separations.
 
  
 +
Splice length of #5-K9 bars with #4 K-bars above wing walls shall be 31 inches (embedment of #5 bars controls over splice length of #4 bars).
  
<center>[[Image:751.12 plastic waterstop on bridge filled joint detail.gif]]</center>
+
All bent bars are formed using stirrup bends except for the K4 and K11 bars.  
<center>* Rustication to be used on highway grade separations only.</center>
 
<center>'''Filled Joint Detail'''</center>
 
  
=== 751.12.2.9 Details of Mounting Light Poles on Safety Barrier Curbs ===
+
'''Ending on Integral End Bents and Semi-Deep Abutments'''
 
+
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
Use when distance between upper and lower construction joint in wings is at least 28½ inches.
 
+
[[image:751.12.1.4.3.1.jpg|center|600px]]
|[[Image:751.12 details of mounting light poles-part plan1.gif|300px]]
+
[[image:751.12.1.4.3.2.jpg|center|650px]]
|colspan="2"|[[Image:751.12 details of mounting light poles-part plan2.gif|325px]]
 
|-
 
!Part Plan
 
!colspan="2"|Part Plan
 
|-
 
|[[Image:751.12 details of mounting light poles-section a-a.gif|330px]]
 
|colspan="2"|[[Image:751.12 details of mounting light poles-section b-b 2010.gif|430px]]
 
|-
 
!Section A-A
 
!colspan="2"|Section B-B
 
|-
 
|[[Image:751.12 details of mounting light poles bar shape 30.gif]]
 
|[[Image:751.12 details of mounting light poles bar shape 13.gif]]
 
|[[Image:751.12 details of mounting light poles bar shape 10.gif]]
 
|-
 
|colspan="3" align="left"|Anchor bolts and nuts shall be in accordance with ASTM A449. Anchor bolts, nuts and washers shall be fully galvanized.
 
|-
 
|colspan="3" align="left"|'''Note to Detailer:''' Extend slab transverse steel to edge of slab in blister region.
 
|-
 
|colspan="3" align="left"|'''Note:''' Conduit not shown for clarity.
 
|}
 
 
 
=== 751.12.2.10 Superelevation Details ===
 
 
 
<center>[[Image:751.12 superelevation details-section thru superelevated slab.gif]]</center>
 
<center>'''Section Thru Superelevated Slab'''</center>
 
 
 
 
 
<center>[[Image:751.12 superelevation details-section thru superelevated approach slab at integral end bent.gif]]</center>
 
<center>'''Section Thru Superelevated Approach Slab at Integral End Bent'''</center>
 
 
 
 
 
<center>[[Image:751.12 superelevation details-section thru superelevated approach slab at non-integral end bent.gif]]</center>
 
<center>'''Section Thru Superelevated Approach Slab at Non-Integral End Bent'''</center>
 
 
 
{|align="center"
 
 
 
|"A"|| = 2'-8" + (Superelev. Slope x 16")
 
|-
 
|"B"|| = 2'-8" - (Superelev. Slope x 16")
 
|-
 
|"C"|| = 8 1/2" + (Superelev. Slope x 16")
 
|-
 
|"D"|| = 8 1/2" - (Superelev. Slope x 16")
 
|}
 
  
=== 751.12.2.11 Expansion Device Movement Gauge ===
+
'''Ending on Shallow Integral End Bents'''
  
All expansion joints shall be equipped with a movement gauge so an historical visual record showing total movement can be established.
+
Use when distance between upper and lower construction joint in wings is less than 28½ inches.
 +
[[image:751.12.1.4.3.3.jpg|center|600px]]
 +
[[image:751.12.1.4.3.4.jpg|center|650px]]
  
<center>[[Image:751.12 expansion device movement guage details-elevation view of movement guage.gif]]</center>
+
'''Ending on Non-Integral End Bents '''
<center>'''Elevation View of Movement Gauge'''</center>
 
  
<center>[[Image:751.12 expansion device movement guage details-plan view of movement guage.gif]]</center>
+
Use when distance between upper and lower construction joint in wings is at least 28½ inches.
<center>'''Plan View of Movement Gauge'''</center>
+
[[image:751.12.1.4.3.5.jpg|center|600px]]
 +
[[image:751.12.1.4.3.6.jpg|center|650px]]
  
 +
===751.12.1.5 Type C (42ʺ Single Sloped Median)===
 +
====751.12.1.5.1 Typical Section====
 +
[[image:751.12.1.5.1.jpg|center|275px]]
  
'''Add following notes to plans:'''
+
====751.12.1.5.2 Typical Section Reinforcement====
 +
[[image:751.12.1.5.2.jpg|center|650px]]
  
Notes:
+
===751.12.1.6 Type A (32ʺ New Jersey Shaped Median)===
 +
Note: Use same grade reinforcing steel in barrier as in slab.
 +
::: Splice length for #5-R bars in barrier  = 37".
 +
::: Do not use this barrier over precast prestressed panels.
 +
[[image:751.12.1.6.jpg|center|375px]]
  
A movement gauge shall be provided on one side of
+
'''Twin Bridge Median Barrier Details'''
bridge at all safety barrier curb expansion joints.
+
[[image:751.12.1.6.1.jpg|center|375px]]
 
All steel shall be galvanized.
 
 
Cost of movement gauge, complete-in-place, shall be
 
included in the contract unit price bid for Safety
 
Barrier Curb.
 
  
== 751.12.3 Medians ==
+
==751.12.2 Two Tube Rail (Top Mounted) TL-4 (NCHRP 350)==
  
 +
'''Guidance'''
  
=== 751.12.3.1 Double Faced Median Barrier Curb (NJ Shape) ===
+
:* Meets TL-4 (NCHRP 350)
 +
:* Typically used on spread box beam bridges.
 +
:* May be used on adjacent box beam bridges where reinforcement is embedded in the beam.
 +
:* Use only in certain applications because of cost. Consult the Structural Project Manager.
 +
:* Acceptable for use when roadway width or site distance is a concern.
 +
:* Curb is intrinsic to TL rating and shall be used. Curb shall be used to prevent drainage over deck.
  
{|
+
'''Details'''
|valign="top"|Note:||Use same grade reinforcing steel in barrier curb as in slab.
+
<center>
|-
+
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
|&nbsp;||Splice length for #5-R bars in barrier curb = 35".
+
|+
 +
| style="background:#BEBEBE" width="300" |'''[http://www.modot.org/business/consultant_resources/bridgestandards.htm Bridge Standard Drawings]'''
 
|-
 
|-
|&nbsp;||Do not use this barrier curb over precast prestressed panels.
+
|align="center"|[http://www.modot.org/business/standard_drawings2/TwoTubeRail.htm Two Tube Rail]
|}
 
 
 
 
 
{|
 
|width="100pt" valign="top"|Note to detailer:||Provide slip-form option for double faced median safety barrier curb. For slip-form option additional #5 cross bracing bars shall be placed on both sides of all joints  and R2 bars shall be one bar.
 
 
|}
 
|}
  
 +
</center>
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
==751.12.3 Median Curbs==
 +
[[image:751.12.3.1.jpg|center|550px]]
 +
:::'''Note:''' All reinforcement shown shall be epoxy coated.
  
|[[Image:751.12 double-faced median barrier curb reinforcement-r2 bar.gif]]
+
Details shown are very general. Consult Design Layout for specific details for each individual structure.  
|[[Image:751.12 double-faced median barrier curb reinforcement-r4 bar.gif]]
 
|-
 
!R2 Bar<br/>Shape 15
 
!R4 Bar<br/>Shape 27
 
|-
 
|colspan="2"|[[Image:751.12 section thru double faced median barreir curb.gif]]
 
|-
 
!colspan="2"|Section Thru Double Faced Median Barrier Curb
 
|-
 
|colspan="2"| &nbsp;
 
|-
 
!colspan="2"|Twin Bridge Median Barrier Curb Details
 
|-
 
|colspan="2"|[[Image:751.12 section thru median curb with open joint.gif]]
 
|-
 
!colspan="2"|Section Thru Median with Open Joint
 
|}
 
  
=== 751.12.3.2 Concrete Median Curbs ===
+
[[image:751.12.3.2.jpg|center|700px]]
 +
[[image:751.12.3.3.jpg|center|650px]]
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
+
==751.12.4 Chain Link Fence==
 +
'''Design Criteria: '''
  
|[[Image:751.12 concrete median curbs-open joint (twin bridges typ).gif]]
+
Dead load of fence fabric weight: 10 pounds per linear foot.  
|-
 
!Open Joint (Twin Bridges Typ.)
 
|-
 
|[[Image:751.12 concrete median curbs-barrier class (no joint).gif]]
 
|-
 
!Barrier Class (No Joint)
 
|-
 
|[[Image:751.12 concrete median curbs-mountable class.gif]]
 
|-
 
!Mountable Class
 
|-
 
|'''Note:''' All reinforcement shown shall be epoxy coated.
 
|-
 
|Details shown are very general.  Consult Design Layout for specific details for each individual structure.
 
|}
 
  
 +
Wind load for chain link or metal fabric fence: GREATER OF 0.015 ksf acting normal to the entire surface per LRFD 13.8.2 OR 0.11 x entire surface x calculated wind pressure (11% is effective surface area per MoDOT practice).
  
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
 
|+'''Concrete Median Curbs (Permissable Alternates)'''
 
|colspan="2" align="left"|'''Bent Bar:'''
 
|-
 
|[[Image:751.12 concrete median curbs (permissalbe alternates)-open joint (twin bridges typ.).gif]]
 
|[[Image:751.12 concrete median curbs (permissalbe alternates)-barrier class (no joint).gif]]
 
|-
 
!Open Joint (Twin Bridges Typ.)
 
!Barrier Class (No Joint)
 
|-
 
|[[Image:751.12 concrete median curbs (permissalbe alternates)-detail a.gif]]
 
|[[Image:751.12 concrete median curbs (permissalbe alternates)-detail b.gif]]
 
|-
 
!Detail "A"
 
!Detail "B"
 
|-
 
|rowspan="2"|[[Image:751.12 concrete median curbs (permissalbe alternates)-field bent bar.gif]]
 
|align="left" valign="bottom"|Add note to plans:
 
|-
 
|align="left" valign="top"|No additional payment will be allowed for the usage of<br/>either alternate anchoring systems.
 
|-
 
|colspan="2" align="left"|'''Resin Anchor:'''
 
|-
 
|colspan="2"|[[Image:751.12 concrete median curbs (permissalbe alternates)-resin anchor choice.gif]]
 
|-
 
|colspan="2"|'''Note:''' All reinforcement shown shall be epoxy coated.
 
|}
 
  
== 751.12.4 Chain Link Fence ==
 
  
 
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
 
{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
Line 798: Line 295:
 
|-
 
|-
 
|[[Image:751.12 pedestrian overpass-superstructure near steps detail a.gif]]
 
|[[Image:751.12 pedestrian overpass-superstructure near steps detail a.gif]]
|align="left"|Design Crieria:<br/>Fence fabric weight = 10#/lin. ft.<br/>Eff. wind area = 0.11 area/sq.ft.
 
 
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!Detail "A"
 
!Detail "A"
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!colspan="2"|Details of Expansion Device Gap
 
!colspan="2"|Details of Expansion Device Gap
 
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|colspan="2"|(**) May conflict with any proposed expansion device sidewalk, consult Structural Project Manager.
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|colspan="2"|(**) May conflict with any proposed expansion device sidewalk, consult Structural Project Manager.  
 
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!colspan="2"|&nbsp;
 
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!colspan="2"|Typical Section Near Splice Gap
 
!colspan="2"|Typical Section Near Splice Gap
 
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|colspan="2" align="left"|'''Note:''' 8'-0" max. post spacing for superstructure.
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|colspan="2" align="left"|'''Note:''' 8'-0" max. post spacing for superstructure.  
 
   
 
   
(*) Locate at about 30'-0" centers with at least one splice gap between pull posts.
+
(*) Locate at about 30'-0" centers with at least one splice gap between pull posts.  
 
   
 
   
 
'''(Add the following notes to the plans.)'''<br/>The maximum spacing allowed between pull posts and end posts is 100 ft. Post brace and 1/2ӯ truss rod are required for panels adjacent to pull posts and end posts only.<br>
 
'''(Add the following notes to the plans.)'''<br/>The maximum spacing allowed between pull posts and end posts is 100 ft. Post brace and 1/2ӯ truss rod are required for panels adjacent to pull posts and end posts only.<br>
Connect the lower end of the 1/2"Ø truss rod to the bottom of the pull posts and end posts to which the stretcher bar is attached.  
+
Connect the lower end of the 1/2"Ø truss rod to the bottom of the pull posts and end posts to which the stretcher bar is attached.
 
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{|border="0" cellpadding="5" cellspacing="1" align="center" style="text-align:center"
|+'''(112") Curved top Pedestrian Fence (Structures)'''
+
|+'''(112") Curved Top Pedestrian Fence (Structures)'''
|(Optional fence detail when requested by district or railroad personnel)
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|(Optional fence detail when requested by district or railroad personnel)  
 
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|[[Image:751.12.4 section aa.jpg|700px]]
 
|[[Image:751.12.4 section aa.jpg|700px]]
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|align="left"|'''Note:''' 8'-0" max. post spacing for superstructure.
 
|align="left"|'''Note:''' 8'-0" max. post spacing for superstructure.
 
   
 
   
(*) Locate at about 30'-0" centers with at least one splice gap between pull possts and end posts.
+
(*) Locate at about 30'-0" centers with at least one splice gap between pull posts and end posts.
 
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[[Category:751 LRFD Bridge Design Guidelines]]
 
[[Category:751 LRFD Bridge Design Guidelines]]

Revision as of 09:05, 12 November 2020

To be found eligible for Federal-aid funding, new roadside safety devices should meet the crash test and evaluation criteria contained in the American Association of State Highway and Transportation Officials’ (AASHTO) Manual for Assessing Safety Hardware (MASH). Since neither FHWA nor AASHTO has a system in place to approve roadside devices, the responsibility is left with the States. In response, MoDOT has developed a MASH Implementation process. All roadside devices that are submitted after November 1, 2019, will be reviewed by the MASH Team for approval to use on Missouri roadways. Prior to November 1, 2019 roadside devices were considered using the criterion set forth in NCHRP Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features”. While MASH requirements are only applicable to the NHS, the following guidelines are recommended for all bridges.

AASHTO LRFD uses the term “railing” to refer to all types of bridge traffic barrier systems used on bridges. MoDOT uses the term “barrier” for solid concrete bridge railing (single-faced on the edge of roadway and dual-faced medians) and the term “railing” for barrier systems consisting of a rail(s) and supports.

Contents

751.12.1 Concrete Barriers

Type D barrier replaced Type B barrier (previously safety barrier curb) as the standard railing for bridges awarded after December 31, 2019. Similarly, Type C barrier replaced Type A barrier (previously median barrier curb). Types H and G shall be used respectively for situations where Types D and C is considered impractical.

751.12.1.jpg

Single sloped barriers have been shown to reduce vehicle climb and increase vehicle stability during redirections when compared to New Jersey shaped barriers. See the following sections for more details on standard barriers. Details for Type G have not been developed, but that does not prevent its use if need dictates.

Concrete barriers were approved for TL-3 or TL-4 test levels in accordance with the MASH 2016 standards. The required MASH 2016 test level for bridges on the National Highway System (NHS) is TL-3, but the expectation is that the TL-4 requirement will be mandated in the next publication.

Test level TL-3 is defined by AASHTO as being “generally acceptable for a wide range of high-speed arterial highways with very low mixtures of heavy vehicles and with favorable site conditions.”

Test level TL-4 is defined by AASHTO as being “generally acceptable for the majority of applications on high-speed highways, freeways, expressways, and interstate highways with a mixture of trucks and heavy vehicles”.

751.12.1.1 Material Properties

Class B-1 Concrete Epoxy Coated Reinforcing Steel
Unit weight (reinforced), wc = 0.150 kcf Yield strength, fy = 60.0 ksi
Compressive strength, f’c = 4.0 ksi Modulus of elasticity, Es = 29,000 ksi
Modular ratio, n = 8
Modulus of elasticity, Ec = 3644 ksi

751.12.1.2 General Details

Regardless of type of barrier shown the following sections are applicable for all concrete barrier types.

Top of barrier shall be built parallel to grade with barrier joints (except at end bents) normal to grade.

All exposed edges of barrier shall have either a 1/2-inch radius or a 3/8-inch bevel, unless otherwise noted.

751.12.1.2.1 Slip Forming

Conventional or slip forming may be used except for situations where slip forming is considered impractical.

See barrier elevation sheets of the barrier standard drawings for the required details.

Slip forming is impractical for prestressed double-tee bridges.

Cross Bracing C Bars

Slip forming requires two No. 5 cross bracing C bars located each side of all joints and at barrier ends.

List C bars in the Bill of Reinforcing Steel and note that bars are for the slip-formed option only.

For barrier segments on top of the bridge deck, use 12-foot C1 bars.

For barrier segments on top of the end bent wings (Type B, D or H):

For segment lengths less than 14'-4", use C2 bars with the following lengths:
Barrier Segment Length
8' to < 9' 9' to < 10' 10' to < 11' 11' to < 12' 12' to < 13' 13' to <14'-4"
Bar Length 5'-9" 6'-9" 7'-9" 8'-9" 9'-9" 10'-6"
For segment lengths 14'-4" to 18 feet, use 12-foot C1 bars.
For section greater than 18 feet, use two sets of 8-foot C2 bars.

Textured Fiberglass Bars

Slip forming requires three four-feet long No. 4 textured fiberglass bars centered at each joint.

751.12.1.2.2 Joints

See barrier elevation sheets of the barrier standard drawings for the required details.

One-fourth-inch joints are located in the barrier at locations of negative moments to prevent cracking in the barrier. Barrier joints may be formed using ¼-inch joint filler in accordance with Sec 1057 or saw cut and seal with silicone joint sealant in accordance with Sec 717. Saw cuts joints may be used with the conventional forming option.

Joints are required when decks are continuous over intermediate bents for both continuous and simple span structures. These joints are also required at the front face of integral end bents. For placement of barrier joints at integral end bents see integral end bent details.

751.12.1.2.2.1.jpg

Additional joints at 12-foot spacing from joint at intermediate bents may be required based on span lengths. The following details provide guidance on locating flexural joints near intermediate bents. This spacing will allow the full yield-line failure pattern to develop for Type D barrier. For simplicity, the 12-foot spacing shall also be used for all other concrete barrier types.

751.12.1.2.2.2.jpg

751.12.1.2.3 Plastic Waterstops

See barrier elevation sheets of the barrier standard drawings for the required details.

Plastic waterstops are typically located inside formed joints to eliminate water seepage problems on grade separations. They shall be excluded over railroads and county roads and are only required on the lower side of superelevated decks.

751.12.1.2.4 Guardrail Attachment

See barrier at end bents sheets of the barrier standard drawings for the required details.

751.12.2.6.jpg

751.12.1.2.5 Superelevation

Superelevated slope, S.E., is in decimal format for the follow calculation, i.e. use 0.04 for 4.0%.

751.12.2.5.1.jpg
751.12.2.5.2.jpg

751.12.1.2.6 Detached Wing Walls

If the detached wing wall has more than one section, see the Structural Project Manager for possible additional joints in the barrier (between sections).

The following details are for illustration purposes only:

751.12.2.6 end bents.jpg

751.12.1.2.7 Details of Mounting Light Poles on Safety Barrier Curbs

751.12.2.7.1 2020.jpg
751.12.2.7.2 2020.jpg

Anchor bolts and nuts shall be in accordance with ASTM A449. Anchor bolts, nuts and washers shall be galvanized in accordance with AASHTO M 232 (ASTM A153), Class C.

Note to Detailer: Extend slab transverse steel to edge of slab in blister region often shown with an additional detail with the slab details.

Note: Conduit not shown for clarity.

751.12.1.3 Type D and H (42ʺ and 32ʺ single sloped railing)

The 42-inch single sloped Type D barrier shall be used for railing on all new or replacement bridge projects except where sight distance is a concern. Type D meets the height requirements for both MASH TL-4 (36ʺ) and Occupational Safety and Health Administration’s OSHA (42ʺ). Type D barrier has been reviewed by the Midwest Roadside Safety Facility (MwRSF) and is compliant with MASH 2016 TL-4. This assessment is applicable for continuous and discontinuous sections of the barrier. Type D barrier shall be used on all redecks and rehabs where the full length of barrier is being replaced with exceptions for the following: 1) sight distance concerns, 2) rating concerns where the weight of the barrier prohibits its use or causes impractical restrictions or costs for the project. The Type D barrier dimensions shall not be adjusted for inclusion of a wearing surface.

The 32-inch single sloped Type H barrier shall be used for railing, upon approval of the SPM or SLE, on all new or replacement bridge projects where sight distance concerns prohibit the use of Type D. Type H has the same front face slope as Type D. The minimum height for MASH TL-3 is 30 inches so there are minimal concerns with Type H for future overlays. The TL-3 height requirement has been updated since the release of SEG 20-001. Type H barrier has been reviewed by the Midwest Roadside Safety Facility (MwRSF) and is compliant with MASH 2016 TL-3. This assessment is applicable for continuous and discontinuous sections of the barrier. When a wearing surface is applied with the newly constructed Type H barrier, a pedestal is recommended to keep the holes for the guardrail attachment in the same location with respect to the top of the barrier.

751.12.1.3.1 Typical Section

All values may be used with both 2.0% and 3/16 inch-per-foot cross slopes.

See EPG 751.12.1.2.5 Superelevation for adjustment of values for different cross slopes.

751.12.1.3.1.jpg

751.12.1.3.2 Typical Section Reinforcement

The single R bar adds to the rigidity of the reinforcement during construction and it is believed to help prevent cracking. The single bar also appears to assist maintaining uniform reinforcement cover.

Splice length for horizontal #5 bars in barrier curb shall be 37 inches.

All bent bars are formed using stirrup bends except for the Type D #5-R1 bars.

All values may be used with both 2.0% and 3/16 inch-per-foot cross slopes.

751.12.1.3.2.jpg

751.12.1.3.3 End of Barrier Reinforcement

See barrier standard drawings for the required details.

All bent bars are formed using stirrup bends.

All dimensions shown may be used with both 2.0% and 3/16 inch-per-foot cross slopes.

751.12.1.3.3.1 Type D Ending on Integral End Bents

Use when distance between upper and lower construction joint in wings is at least 28½ inches.

751.12.1.3.3.1.1.jpg
751.12.1.3.3.1.2.jpg
751.12.1.3.3.2 Type H Ending on Integral End Bents

Use when distance between upper and lower construction joint in wings is at least 28½ inches.

751.12.1.3.3.2.1.jpg
751.12.1.3.3.2.2.jpg
751.12.1.3.3.3 Type D Ending on Shallow Integral End Bents

Use when distance between upper and lower construction joint in wings is less than 28½ inches.

Formulas extend bars to within 1½ʺ of lower construction joint.

Use Shape 27 for K3 bar in Barbill program to obtain correct weight and length. Revise Shape 27 on plan sheet to Shape 50 and add shape to bending diagrams.

751.12.1.3.3.3.1.jpg
751.12.1.3.3.3.2.jpg
751.12.1.3.3.4 Type H Ending on Shallow Integral End Bents

Use when distance between upper and lower construction joint in wings is less than 28½ inches.

Formulas extend bars to within 1½ʺ of lower construction joint.

Use Shape 27 for K3 bar in Barbill program to obtain correct weight and length. Revise Shape 27 on plan sheet to Shape 50 and add shape to bending diagrams.

751.12.1.3.3.4.1.jpg
751.12.1.3.3.4.2.jpg
751.12.1.3.3.5 Type D Ending on Non-Integral End Bents

Use when distance between upper and lower construction joint in wings is at least 28½ inches.

751.12.1.3.3.5.1.jpg
751.12.1.3.3.5.2.jpg
751.12.1.3.3.6 Type H Ending on Non-Integral End Bents

Use when distance between upper and lower construction joint in wings is at least 28½ inches.

751.12.1.3.3.6.jpg
751.12.1.3.3.7 Type D Ending at End of Slab (Redecks)

Splice length of #5 K12 and #5 K13 bars with #5 R-bars shall be 37 inches.

751.12.1.3.3.7.jpg
751.12.1.3.3.8 Type H Ending at End of Slab (Redecks)

Splice length of #5 K7 bars with #5 R-bars shall be 37 inches.

751.12.1.3.3.8.jpg

751.12.1.4 Type B (32ʺ New Jersey Shaped Railing)

The 32-inch New Jersey shaped railing, previously referred to as safety barrier curb, shall not be used on new construction projects. This includes redecks and rehabs where the full length of barrier is being replaced. Type B barrier may be replaced in kind where spot work is required (i.e., expansion joint replacements). For wearing surface projects, where the grade is not being increased more than 2 inches, the existing Type B barrier may be used in place in accordance with EPG 751.1.3.4 Barrier or Railing Type, Height and Guidelines for Curb Blockouts.

751.12.1.4.1 Typical Section
751.12.1.4.1.jpg

See EPG 751.12.1.2.5 Superelevation for adjustment of values for different cross slopes.

751.12.1.4.2 Typical Section Reinforcement

The single R bar adds to the rigidity of the reinforcement during construction and it is believed to help prevent cracking. The single bar also appears to assist maintaining uniform reinforcement cover.

Splice length for horizontal #5 bars in barrier curb shall be 37 inches.

All bent bars are formed using stirrup bends except for the R1 bars.

751.12.1.4.2.jpg
751.12.1.4.3 End of Barrier Reinforcement

See barrier ending on end bents sheets of the barrier standard drawings for the required details. The bars shown below are for barrier ending on wing walls; see barrier ending at end of slab sheet of the barrier standard drawings for reinforcement details for barrier ending on slabs.

Splice length of #5-K9 bars with #4 K-bars above wing walls shall be 31 inches (embedment of #5 bars controls over splice length of #4 bars).

All bent bars are formed using stirrup bends except for the K4 and K11 bars.

Ending on Integral End Bents and Semi-Deep Abutments

Use when distance between upper and lower construction joint in wings is at least 28½ inches.

751.12.1.4.3.1.jpg
751.12.1.4.3.2.jpg

Ending on Shallow Integral End Bents

Use when distance between upper and lower construction joint in wings is less than 28½ inches.

751.12.1.4.3.3.jpg
751.12.1.4.3.4.jpg

Ending on Non-Integral End Bents

Use when distance between upper and lower construction joint in wings is at least 28½ inches.

751.12.1.4.3.5.jpg
751.12.1.4.3.6.jpg

751.12.1.5 Type C (42ʺ Single Sloped Median)

751.12.1.5.1 Typical Section

751.12.1.5.1.jpg

751.12.1.5.2 Typical Section Reinforcement

751.12.1.5.2.jpg

751.12.1.6 Type A (32ʺ New Jersey Shaped Median)

Note: Use same grade reinforcing steel in barrier as in slab.

Splice length for #5-R bars in barrier = 37".
Do not use this barrier over precast prestressed panels.
751.12.1.6.jpg

Twin Bridge Median Barrier Details

751.12.1.6.1.jpg

751.12.2 Two Tube Rail (Top Mounted) TL-4 (NCHRP 350)

Guidance

  • Meets TL-4 (NCHRP 350)
  • Typically used on spread box beam bridges.
  • May be used on adjacent box beam bridges where reinforcement is embedded in the beam.
  • Use only in certain applications because of cost. Consult the Structural Project Manager.
  • Acceptable for use when roadway width or site distance is a concern.
  • Curb is intrinsic to TL rating and shall be used. Curb shall be used to prevent drainage over deck.

Details

Bridge Standard Drawings
Two Tube Rail

751.12.3 Median Curbs

751.12.3.1.jpg
Note: All reinforcement shown shall be epoxy coated.

Details shown are very general. Consult Design Layout for specific details for each individual structure.

751.12.3.2.jpg
751.12.3.3.jpg

751.12.4 Chain Link Fence

Design Criteria:

Dead load of fence fabric weight: 10 pounds per linear foot.

Wind load for chain link or metal fabric fence: GREATER OF 0.015 ksf acting normal to the entire surface per LRFD 13.8.2 OR 0.11 x entire surface x calculated wind pressure (11% is effective surface area per MoDOT practice).


751.12.4 superstructure near steps.jpg
Superstructure Near Steps
 
751.12.4 superstructure near end panel.jpg
Superstructure at or Near End Panel
 
751.12 pedestrian overpass-superstructure near steps detail a.gif
Detail "A"  


751.12 pedestrian overpass-landing.gif 751.12 pedestrian overpass-section thru fence.gif
Landing Section thru
Fence
 
751.12.4 handrail bracket.jpg
Details of Handrail Bracket
 
751.12.4 rail post connection.jpg
Rail Post Connection (Typical)
 
751.12.4 plan of floor plate.jpg
Plan of Floor Plate
 
751.12.4 details of expansion device gap.jpg
Details of Expansion Device Gap
(**) May conflict with any proposed expansion device sidewalk, consult Structural Project Manager.
 
751.12.4 typical section near splice gap.jpg
Typical Section Near Splice Gap
Note: 8'-0" max. post spacing for superstructure.

(*) Locate at about 30'-0" centers with at least one splice gap between pull posts.

(Add the following notes to the plans.)
The maximum spacing allowed between pull posts and end posts is 100 ft. Post brace and 1/2ӯ truss rod are required for panels adjacent to pull posts and end posts only.
Connect the lower end of the 1/2"Ø truss rod to the bottom of the pull posts and end posts to which the stretcher bar is attached.


(112") Curved Top Pedestrian Fence (Structures)
(Optional fence detail when requested by district or railroad personnel)
751.12.4 section aa.jpg
Section A-A
 
751.12.4 curved top.jpg
Curved Top Pedestrian Chain Link Fence
(Galv. Steel) on Sidewalk
NOTE: 8'-0" Max. post spacing for superstructure.

(*) Locate at about 30'-0" centers with at least one splice gap between pull posts.

The maximum spacing allowed between pull posts and end posts is 100 feet. Post brace and 1/2"Ø truss rod are required for panels adjacent to pull posts and end posts only.
Connect the lower end of the 1/2"Ø truss rod to the bottom of the pull posts and end posts to which the stretcher bar is attached.

 
751.12.4 details at expansion device gap.jpg
Details at Expansion Device Gap
(**) May conflict with any proposed expansion device sidewalk, consult Structural Project Manager.
 
751.12.4 typical section near splice gap (112 in).jpg
Typical Section Near Splice Gap
Note: 8'-0" max. post spacing for superstructure.

(*) Locate at about 30'-0" centers with at least one splice gap between pull posts and end posts.