A field study of an aluminium box culvert subjected to backfill and live load is correlated with a laboratory load testing of a rib-reinforced plate. Stress concentration and distribution of stress are examined in the region where bolts connect reinforcing ribs to the corrugated plate. Moments and thrusts on ribs and plates are computed to examine composite behaviour. Stresses in the region of bolts that attach ribs to the corrugated plate are only in approximate agreement with results obtained from the finite-element computer program CANDE. Experimental data suggest that plate distortion near the assembly bolts results in local bending stresses. Field measurements show that rib and plate forces act as noncomposite members during back filling, but respond compositely with the application of live load. A flat, corrugated plate with no-rib, one-rib, and two-rib combinations was tested in the laboratory under a concentrated load acting at the centre and a constant bending moment. Stresses were found to have significant variations perpendicular to the corrugations that may be corrected with a shift in the neutral axis. Stresses are in agreement with the constant ratio of composite response for the rib and corrugated plate when stresses are measured between bolts. Stress concentrations and local distortions at rib ends were duplicated in the laboratory.
Abstract