Shake Table Seismic Performance Assessment of Lightly Reinforced Concrete Block Shear Walls

There is a need to develop a reinforced masonry (RM) seismic performance database (SPD) of experimental results in order to facilitate adoption of RM seismic force-resisting systems (SFRS) in the next generation of performance-based seismic design (PBSD) codes. As a contribution to this SPD, and within a larger ongoing research program, this paper reports on recent shake table tests performed on lightly reinforced masonry shear walls. The test walls covered a range of design parameters to facilitate benchmarking, further performance investigation, and calibration of numerical models as well as future development of fragility curves within the context of PBSD. The design parameters of the walls were selected to meet the requirements of the lightly reinforced conventional construction category. This particular RM wall category is not permitted in moderate and high seismic zones in the Canada based on Canadian masonry design code. Within the context of PBSD, the wall seismic performances, in terms of damage levels observed during the shake table tests, were generally acceptable considering the levels of earthquake record intensities to which the walls were subjected. The walls did not experience any damage during low amplitude tests, corresponding to frequent minor earthquake events, incurred repairable damage under higher level tests, and maintained their integrity under the highest level record selected to mimic the seismic hazard levels of the highest seismicity zones in Canada. The tests also demonstrated the capability of lightly reinforced masonry shear walls to adequately dissipate energy through nonlinear flexural response. The test results are expected to contribute to the growing SPD of RM SFRS components, and to facilitate a better understanding of the behavior and performance of lightly reinforced masonry walls under realistic seismic loads.