Experimental Study On Seismic Performance Of Brick Concrete Structure

Fired common bricks has been widely applied to residential, school, hospital and office buildings concerning its convenience and popular price. Meanwhile multi-story brick buildings accounted for a large proportion in the damaged and collapsed buildings during the Wenchuan Earthquake in2008. Therefore it is necessary to study the multi-story brick buildings. Then two layer confined brick masonry specimen has been set for the study of the self-vibration characteristic test and the seismic performance test in this paper.The properties of the fired common bricks and the mortar have a significant impact on the performance of the structure in these tests. Therefore first of all, the mechanical performance test on the material is produced to ensure all index satisfying the provisions of the design and the code. It includes the fired common brick compressive strength test, the mortar cube compressive strength test, concrete compressive strength test, the steel bar tensile test, the shear strength test of the masonry along a continuous seam section and the masonry compressive strength test.The results of the self-vibration characteristic test include frequency, vibration mode and damping ratio after the construction of the model. Meanwhile the comparison between the test results and modeling simulation results by Sap2000was made. The comparison of the results show multi-story brick buildings with tie-columns and ring-beams are inclined to1-th vibration and oscillate lengthwise (in the direction of X). The self-vibration characteristic test was produced for a second time after the pseudo-dynamic test. The minor frequency and the same vibration condition (in the direction of X) are obtained.Pseudo-dynamic test and pseudo-static test are carried out to investigate the behavior of the model structure. According to Intensity7, adjusted Northridge record was selected to be the ground motion input in the pseudo-dynamic test. The time-history curves of the acceleration, velocity, displacement and restoring force of the structural response were obtained besides the time-history curves of the measuring points of the structure. Also the steel strain of the tie-:olumns and the hysteresis loops of the structure were obtained. The results from the pseudo-dynamic test and the pseudo-static test show the walls take most responsibility of earthquake action. Tie-columns confine the development and failure of walls and ring-beams ensure the integrity between tie-columns and walls. Both of them reduce the lateral displacement of walls. The hysteresis loop in the pseudo-static test is better developed, but also the stiffness presents evident degradation which shows the confined masonry structures possess the ability to strongly resist the deformation and good ductility.