Field test performance of buried flexible pipes under live truck loads

The objectives of this study are to determine the short-term performance for shallowly buried [2,438 mm (up to 8-ft burial depth)] flexible pipes, evaluate joint performance requirements, and verify AASHTO design assumptions in the light of field test data from in situ measurements. The installation, instrumentation, and field test procedures are presented for high-density polyethylene (HDPE), PVC, and metal pipes under 2D, 1D, and 0.5D burial depths, where D is the pipe diameter. The field test is performed on 914 mm (36 in.) and 1,219 mm (48 in.) pipe diameters. A tandem dump truck is selected for the pipes under 2D burial depth, while the Florida Department of Transportation truck is adopted for the pipes under 0.5D and 1D burial depths. The field test results are presented in terms of the soil pressure distribution around the cross section, as well as the vertical and horizontal pipe diameter changes during construction and under the live load. Special emphasis is given to circumferential wall strains. The validity of the modified Iowa and Meyerhof formulae proposed to predict the horizontal deflection of buried pipes is also investigated.