AbstractThis paper investigates the structural performance and soil–culvert interaction of large-span precast concrete three-sided culverts (TSCs). Three TSCs with flat top slabs have been instrumented with 30 pressure cells and 56 strain gauge vibrating wire sensors. The test culverts cover a range of spans from 7.3 to 13.5 m, each under a different installation condition. The instrumentation plans were established based on the results of three-dimensional finite-element analyses. This paper makes a contribution to (1) recommendations on the design of instrumentation plan and sensors selection criteria; (2) details of the instrumentation installation procedure and corresponding modifications to accommodate specific conditions of each culvert; and (3) field measurements and analysis of the data from a culvert covered with 3.2 m of backfill soil. Useful guidelines are provided for instrumenting similar structures. The field data were used to evaluate the current design practice and evaluate the Canadian Highway Bridge Design Code (CSA 2014) provision regarding earth loads on TSCs. The obtained data reveal the nonuniform distribution of the earth pressures on the top slab with an average vertical arching factor of 1.05. Also, the strain gauge measurements indicate the development of bending moment at the base of the sidewall, which was attributed to the rotation of the strip footing predicted from the developed preliminary numerical analysis.