Full-Scale Testing of Three-Sided Precast Concrete Arch Sections

The use of precast, three-sided arch culverts has become popular for new and replacement short-span bridges because of rapid construction time and minimal environmental impact on the waterway. The arching action in the top slab creates a horizontal thrust, and the surrounding fill enables lateral earth pressures to develop in the backfill based on this thrust. The lateral pressure behind the legs potentially permits the bridge to carry larger loads than it could without backfill confinement. This paper reports the results of three full-scale tests of three-sided culverts. The first test consists of a field test using an overload vehicle on a site with a newly constructed, 12.8-m clear-span, three-sided, precast arch bridge. The second specimen, an individual 6.1-m arch section, was tested in the laboratory for service-level loading in two configurations. One unrestrained configuration and one setup with steel sections simulating lateral restraint at two points along the wall were tested; additionally, the 6.1-m arch specimen was tested to failure without lateral restraint. The third specimen, an 11.0-m clear-span arch section, was tested to failure without any lateral restraint. The results of the three full-scale tests are presented and discussed. In addition, nonlinear models were calibrated with the experimental tests and then analyzed with the factored design loads to determine whether the demand, including nonlinear effects within the section, exceeded the arch section capacity.