Field measurements and analysis of a large-diameter flexible culvert

This paper describes field measurements and analysis carried out on the Elkhart Creek soil–arch culvert structure in British Columbia, Canada. The structure has a span of 13.4 m, a rise of 7.3 m, and a soil cover of 9.6 m. The original structure collapsed during backfilling in October 1987. A new structure of the same design was built in the fall of 1989, and because of controversy regarding the design thrust value, it was instrumented to measure thrust and displacements in the arch. Displacements and stresses in the soil were also measured. The measured thrust values were much lower than expected and indicated that significant positive soil arching occurred, similar to that observed at the Vieux Comptoir soil–stucture in Quebec in 1975. A nonlinear finite element analysis of the soil–structure system was carried out simulating the construction procedures used, and the computed response was compared with the measurements. The computed and observed responses were in reasonable agreement in all aspects, namely thrust, displacements, and soil stresses, provided an allowance was made for slip at the bolted connections. Key words : culvert, finite element, arching, stress, displacements.