Experimental Campaign Addressing Lap-Splices under Cyclic Loading

Many existing bridges were built before modern seismic design guidelines were written. This means that particularly in countries with moderate seismicity where another type of loads such as gravity, wind or snow are more demanding, the seismic hazard may have been underestimated in the past years. Past experience shows that critical details, including lap-splices on the potential plastic hinge region above the foundation and low transverse reinforcements ratios, can lead to a small deformation capacity of the existing bridge piers and therefore to a possible major structural damage. The performance of RC members featuring lap splices was extensively studied in the past. However, a large number of authors focused on the force capacity of lap splices while their deformation capacity was rather neglected. This topic has become a target of interest only recently. This dissertation represents the first part of a research project developed at École Polytechnique Fédérale de Lausanne that has the final goal of presenting a constitutive law capable of predicting the lap splice behavior, in particular its deformation capacity. The dissertation presents an experimental campaign regarding the lap splice performance under cyclic loading. This experimental campaign gives continuity to the experimental campaigns presented by Bimschas (2010) and Hannewald et al. (2013), where three large-scale piers featuring lap splices near the foundation were tested. Three specimens representing a boundary region of the previously specimens are presented in this dissertation. The test specimens subjected to the same cyclic load history only differ regarding the transversal reinforcement. Particular attention is given to the slippage between the rebars and the steel strains in the lap splice zone. These tests along with the results of future specimens intend to create a database that will allow to validate the future expression mentioned above