Shear behaviour of concrete box culverts

A research program was developed to investigate the shear behaviour of precast reinforced concrete box culverts. Experiments were conducted on twelve box culvert specimens with six different designs. Three specimen types were designed with reinforcement ratios in conformity with Ontario Provincial Standards Specifications (OPSS) 1821, while the remaining three had larger reinforcement ratios for applications with large depths of soil cover over the culverts.; Sections designed in accordance with OPSS 1821 specifications exhibited predominantly flexural behaviour. Shear failures were observed in several of the deep earth cover designs. All specimen designs were found to be conservative. Calculations were performed using Canadian Highway and Bridge Design Code (CHBDC) and American Association of State Highway and Transportation Officials (AASHTO) specifications. CHBDC code shear provisions were found to yield conservative shear strength predictions. Discussion is presented identifying areas of weakness and lack of clarity in the current codes governing box culvert design.