Performance of a Reinforced Concrete Box Culvert Installed in Trapezoidal Trenches

The performance of embankment installation (EI) and trench installation (TI) culverts has been investigated through experimental, numerical, and analytical methods. However, there are few studies on the performance of trapezoidal TI (TTI) culverts. Therefore, this study was performed to investigate the complex soil-structure interaction and to provide reference for the design of TTI culverts. First, field tests were conducted to measure the vertical earth pressure on the TTI culvert. Then, numerical simulations were performed to investigate the performance of TTI culverts. With the validation of the numerical model, parametric studies were carried out to investigate the important influencing factors (i.e., the slope angle of the trench, the bottom width of the trench, the culvert dimensions, and the stiffness of backfill adjacent to the culvert) on the culvert performance. This study reveals that the vertical earth pressure on the TTI culvert is significantly different from that on EI and TI culverts. The magnitude of the vertical earth pressure and deformation of the TTI culvert are influenced by the soil arches as long as the backfill is high enough. Generally, it is suggested that soil arch effects should be considered in the design of TTI culverts.