Category:726 Rigid Pipe Culverts
From Engineering Policy Guide
726.1 Construction Inspection for Sec 726
Placement of rigid pipe is a somewhat more demanding operation than is true for corrugated metal pipe since relatively short sections of pipe must be joined together in the field to provide a completed pipe which meets line and grade requirements. Since normal manufacturing tolerances sometimes present the inspector with problems due to adjacent sections which do not exactly match, it is suggested that all sections be properly positioned to obtain proper alignment and grade at flow line. This will provide the least obstruction to free flow due to previously mentioned irregularities.
Bedding material must provide uniform support to prevent uneven settlement and opening of joints. The lower portion of bedding must be shaped as required by Sec 718.104.22.168 or as required by the manufacturer’s installation procedures submitted for special design reinforced concrete pipe.
Sealing of joints and lift holes must be carefully inspected before backfilling to assure that no voids remain. Any leakage at joints could erode supporting material and lead to failure by collapse or separation of sections.
Instructions in Sec 722.214.171.124 pertaining to backfilling are of equal importance for rigid pipe. Although the pipe is not easily distorted, it is very easy to displace individual sections by improper methods.
Final measurements are not required except for authorized changes which will be added to or deducted from plan quantity. The inspector should note in the diary when the culverts were built and that they were built according to plan or approved changes.
An inspection of all new installed pipe should be made. It should be tested for the criteria set forth in the Inspection heading in the spec. book for the applicable pipe. The inspector should make sure the pipe is from an approved source and is properly marked. The inspector should not accept any pipe that does not have a MoDOT pipe identification number listed on the bill of lading. Please note, each type, size, class, etc. of pipe on the bill of lading should have a unique MoDOT identification number. The associated SiteManager records should be reviewed to confirm that the details recorded there are representative of the material on the job site. A disposition remark should be made on each sample record indicating arrival of the material, its condition, and the accuracy of the record. Concrete pipe is inspected at the plant by District Construction and Materials. Concrete pipe should have an industry quality control stamp, i.e., ACPA or NPCA. There will not be a MoDOT OK stamp. Tape measures or other devices can be used for a preliminary measurements for diameter deflection. If the results are in question the mandrel test will serve as the definitive test for deflection. Always make sure that when testing the right measurement unit is used. Pipe can be produced in either English or Metric units. Make sure the measurements are taken in the same units as the pipe was produced. The Qualified List for each type of pipe will indicate the manufacturer's identification mark and the units (English or metric) that was used to fabricate the pipe.
726.2 Material Inspection and Laboratory Testing for Sec 726