Experimental Study On The Effect Of Fire Exposure Cases On The Seismic Behavior Of Concrete Short Columns After High Temperature

The fire-resistant method has some influence on the seismic performance of the reinforced concrete short columns after high temperature,and no relevant literature has been found at present.In this paper,the experimental study on the seismic behavior of reinforced concrete short columns with different fire modes is carried out,and the finite element software is used to simulate the fire and the one-way push.The main work and conclusions of this paper are as follows:In this experiment,five components were fabricated,one of which was not affected by fire,and the other four were as follows: affected by fire from four sides,affected by fire from three sides,affected by fire from two adjacent sides.The quasi-static test was used to study the failure behavior,shear capacity,stiffness,ductility and energy dissipation capacityof reinforced concrete short columns after high temperature.The results of the test are listed below.Compared with Z-1,the cracking load of Z-2,Z-3,Z-4 and Z-5 decreased by 39.89%,25.40%,15.87% and 23.81%;the yield load decreased by41.61%,14.81%,6.61% and 15.67%;the peak bearing capacity decreased by 41.19%、18.59%、6.63% and 18.82%;the initial stiffness decreased by 58.95%,51.66%,19.44% and 32.20%,the ductility decreased by 22.34%,19.50%,10.64% and 14.54%.The cumulative hysteretic energy dissipation decreased by 46.16%,27.59%,12.35% and 28.87%in the third cycle of displacement angle of 2/100.Compared withZ-3 and Z-6,the effects of the loading direction on the seismic performance of the short columns were not found.The numerical analysis model of concrete short column is established by using ABAQUS software,and the maximum temperature of the node is introduced into the one-way push analysis model of reinforced concrete short column after high temperature.The finite element model can simulate the temperature rising process of the internal measurement point and the shear capscity of the components after high temperature,but the P-△ curve simulation accuracy needs to be further improved.