Rigid Culvert Finite Element Analyses

Abstract

Time‐independent analyses of five of ten zones of a dummy reinforced concrete pipe at Cross Canyon are presented. All five zones are characterized by “positive projection,” four in a narrow, vertical‐sided trench with a projection ratio of about 0.4, one, almost fully projecting. Two zones (1 and 4) were surmounted by ordinary embankment material, three entrenched zones (8, 9 and 10), by low modulus embankment inclusions (polystyrene plank, uncompacted soil, and baled straw). Each zone was heavily instrumented for assessment of peripheral soil pressures, internal strains, and wall displacements. Fluid settlement platforms and additional stressmeters were placed in the embankment. Instruments were monitored at frequent increments of overfill. A finite element code, REA, (for Reinforced Earth Analysis) was adapted to special needs of pipe and boundary geometry and nonlinear, incremental, embankment construction. Correlations were established between finite element results and certain parameters obtained from extensive instrumentation at Zones 1, 4, 8, 9 and 10. Initial analyses employed asymmetrical boundaries determined by presurveying canyon cross‐sections. Additional analyses compared finite element results obtained with a more economical, symmetrical mesh.