Scaled Model Test for Efficient Arrangement of Steel Reinforcement in Bridge Pier Caps

Because variations associated with the strut-and-tie model (STM) in the design of pier caps could lead to over-reinforcement of steel rebars, special attention should be paid to using STMs for reasonable rebar arrangements. Here, static loading tests were conducted on three scaled-model specimens of bridge pier caps to investigate the efficient arrangement of steel reinforcement in the bridge pier cap design. To determine the effect of the loading condition on the pier cap behavior, T-type pier caps with two or four support bearings were tested under realistic boundary conditions, using three hydraulic actuators. The tested load-resistance capacities were compared with the STM predictions. The study revealed that the arrangement of vertical ties in the STM along the shear critical section in the column's vicinity could induce excessive vertical shear reinforcement. The experimental results showed that all specimens designed using the STM with no unnecessary vertical ties exhibited flexure failure without any sudden shear failure. The effect of load distribution on the pier cap behavior was evaluated using different numbers of support bearings.