Full-Scale Field Tests on Longitudinal Uplift Response of Corrugated Metal Pipe

In response to problems with corrugated metal pipe (CMP) culvert uplift failures caused by unbalanced inlet hydraulic loading, full-scale field testing and numerical analysis were undertaken to develop a rational design methodology for CMP inlet tiedowns. Four uplift tests performed on a 2.44-m-diameter CMP under different backfill cover, foreslope, and restraint conditions are described. The objectives of the tests were to gain insight into the soil-structure interaction processes and to provide data for verification of the performance of the finite-element model used to calculate the required restraint forces. The test results indicate that the backfill foreslope has a significant effect on uplift response. For example, the force required to lift the CMP inlet 25 mm was about 50 percent greater with 0.6 m of backfill cover and a full 2:1 foreslope than with 0.6 m of backfill cover and approximately 4 m of the CMP exposed beyond the toe of the backfill foreslope. These results indicated that appropriate modeling of the soil-structure interaction and interface behavior in the foreslope region is extremely important.