Category:1033 Precast Drainage Units

This article establishes procedures for inspecting, acceptance and reporting of precast reinforced concrete manhole and drop inlet sections and appurtenances such as grade rings, tops and special sections. Refer to Sec 1033 for MoDOT’s specifications.

For Laboratory testing and sample reporting procedures, refer to EPG 1033.4 Laboratory Testing Guidelines for Sec 1033.

Acceptance of precast drainage units may be on the basis of an approved, industry recognized QC program, inspection by MoDOT, or a combination of the two methods, at the discretion of the district. Approval of QC programs is the responsibility of Central Office. Currently the QC programs of the American Concrete Pipe Association (ACPA) and National Precast Concrete Association (NPCA) are approved. Prior to allowing production under a QC program, the district must confirm that the producer's certification is current and that it covers the material being produced. The district must initially, and on a recurring basis, confirm that the producer routinely and diligently follows the requirements of the QC program, and that material produced for MoDOT is specification compliant. This confirmation will be in the form of a quality assurance visit, including a review of all applicable paperwork, a review of the producer’s QC process, and an active inspection of current production (a SiteManager plant inspection record is required - 1033XXQCP). When a producer is allowed by the district to produce under a QC program, the producer must agree to notify the district in advance of their intended production schedule. Acceptance of precast drainage units with MoDOT inspection is to be based on the inspection of materials being incorporated into the sections, the amount and placement of reinforcement, and inspection of the finished section.

If Class B or B-1 concrete is used, compressive tests and absorption test specimens will not be required. If a commercial concrete is used, both compressive tests and absorption tests will be needed.

1033.1 Apparatus

(a) Rule with suitable graduations to accurately measure the material to be inspected.

(b) OK - MoDOTstamp.

(c) Weather-resistant marking materials.

(d) Applicable AASHTO specifications.

1033.2 Procedure

Inspection and reporting of coarse aggregate, fine aggregate, cement, fly ash and reinforcing steel shall be as described in EPG 1026 Reinforced Concrete Culvert Pipe unless Class B or B-1 concrete is used. When Class B or B-1 concrete is used; materials, proportioning, mixing, slump and transportation of portland cement concrete shall be in accordance with Sec 501. Air entrainment will not be required.

No matter what type of concrete is used, Sec 1033 lists an absolute minimum proportion of cement needed.

All reinforcing steel used for precast drainage units shall be in accordance with the PAL process. An inspector should visually check PAL materials and verify paperwork when possible.

If needed, compressive tests may be made on either standard rodded concrete cylinders or cylinders compacted and cured in a similar manner to the sections under consideration for acceptance, or, at the option of the manufacturer, on cores drilled from the wall of the sections in accordance with AASHTO M 199. Cylinders or cores are to be tested in accordance with AASHTO M 199.

Occasional individual cylinders or cores may fall below the design strength for some unknown reason. The allowances for deficient strengths are described under AASHTO M 199. Compressive tests are to be performed at the fabricating plant unless questionable results are being obtained, in which case the cylinders or cores may be submitted to the Laboratory.

If needed, absorption tests shall be made on a core cut from the full wall thickness.

The sections are to be inspected for amount and placement of reinforcing steel. The amount and placement of reinforcing steel in rectangular drop inlets is to be as shown in the plans. Reinforcing steel for all other sections is to be as specified in Sec 1033.

The finished sections are to be examined for conformance to dimensions, workmanship, and marking. Permissible variations in dimensions and rejection criteria for workmanship are specified in Sec 1033. Each section shall be marked as follows by the manufacturer by indenting into the concrete or painting on with waterproof paint:

(a) Date of manufacture.

(b) Name or trademark of the manufacturer.

(c) If the manufacturer is allowed to produce under an approved QC program, each section considered by the manufacturer to be specification compliant will be marked by the manufacturer with the indicator required by the QC program. Sections rejected by the manufacturer may be marked or handled in accordance with the QC program but the rejection must be clearly indicated.

(d) If the manufacturer is allowed to produce under an approved QC program, each section to be shipped will be marked by the manufacturer with the Sample ID number provided by the district. If the producer has marked a piece with a Sample ID number, and the section is found to be unacceptable during an audit, the Sample ID number must be neatly obliterated.

Sections accepted by MoDOT inspection are to be marked with "OK-MoDOT" by the inspector. Rejected sections are to be marked with a single vertical mark, near the manufacturers marking and shall be made with weather resistant marking material.

Procedures for submitting special or modified designs are described in Sec 1033.4.2. Additional information related to special designs may be found in EPG 106.16 Special Designs. Special and modified design units, at the discretion of the district, may not be accepted under a QC program.

1033.3 Report

Units inspected and accepted by a QC program must be reported to the district prior to shipment. Shipment information will be recorded in SiteManager by the district. The district will provide the producer with the Sample ID number(s) for the product. A single Sample ID may represent multiple sections, as may be indicated in the Sample Record. The producer will place the Sample ID number on the product indelibly. For units produced with MoDOT inspection, SiteManager will be used to document all accepted sections, component parts, and test samples necessary to complete inspection of precast drainage units.

If class B or B-1 concrete is used, the plant inspector located at the concrete proportioning plant shall create a SiteManager sample record for each day's pour documenting the class of concrete poured and the units manufactured from that pour. The name of the manufacturer or set-up must be shown.

Finished sections shall be reported through SiteManager. The following information is to be included on the appropriate template, in addition to that normally required for a sample record:

(a) Quantity, size and length, that is: 8 each, 2 ft. x 3 ft. to 6.0 ft. long (8 each, 600 mm x 900 mm to 1800 mm long).

(b) Date of production.

(c) Description (as to type of inlet, etc.).

(d) ID No. or reference number, if needed.

Specific test templates exist in SiteManager for Manholes, Drop Inlets and Type S Headwalls. These templates may be used in place of the free form test and do not require all the above information. The above information may be entered, but is considered optional since lumping of similar sections is allowed.

SiteManager is to be used to create the sample record for submitting cylinders or cores to the Laboratory.