LARGE SCALE QUASI-STATIC CYCLIC TESTS OF EXISTING BRIDGE PIERS

摘要

Older existing bridge piers often show detailing which from today's perspective would no longer be acceptable for seismic design. Two of the most common deficiencies are low transverse reinforcement ratios and lap-splices at the pier base. The former may cause premature shear failure, thus reducing the displacement capacity of the pier, while the latter can lead to a degradation of flexural strength during inelastic cyclic loading which can cause an increase in displacement demand. As the flexural strength defines the shear demand there may also be an interaction between the lap-splice behavior and potential shear problems. In this paper the results of two large scale quasi-static cyclic tests on bridge piers are presented. Both test units had essentially the same design featuring a low transverse reinforcement ratio with the only difference being that one unit had a lap-splice at the base while the other one had continuous reinforcement. This way a potential interaction between lap-splice behavior and potential shear problems could be studied. A comparison of the experimental results with existing models to describe both failure modes is presented.