Shaking table tests on the seismic performance of rural row-lock wall masonry structure subjected to mainshock-aftershock earthquake sequence

Abstract

The mainshock of an earthquake sequence is usually followed by a series of aftershocks that further aggravate the damage to structures. Row-lock wall masonry structures are widely distributed in rural areas of China, and their seismic performance is poorer than that of solid wall unreinforced masonry structures. To study the seismic performance of row-lock wall masonry structures with the action of a mainshock-aftershock earthquake sequence, two half-scale row-lock wall masonry structure models were made for a shaking table test. One model was unreinforced and the other was confined by the ring beam and the constructional column. The seismic damage characteristics, natural frequency variation, maximum acceleration, and displacement response of each model for the mainshock and aftershock tests were compared and analyzed. The test results showed that the existence of earthquake-resistant constructional measures enhanced the shear strength of the model, limited the propagation range of cracks, and effectively improved the integrity of the earthquake-damaged model. The cumulative damage effect of an aftershock cannot be ignored, and consideration of only the safety of the structure for a mainshock has limitations. When the model was seriously damaged, the cumulative damage effect of the aftershock was more noticeable. The maximum inter-storey displacement for aftershock tests essentially cannot exceed that for the corresponding mainshock tests, indicating that the inter-storey drift is not suitable for evaluating the cumulative damage effect of an aftershock on a row-lock wall masonry structure. The present study can provide a reference for earthquake disaster prevention and reduction in rural areas.