The Seismic Performance Analysis Of RC Frame With The Vertical Unbalanced Arrangement For Infilled Walls

Lots of previous earthquake damage investigations show that in some smalltowns, many multilayer frame structures along the street had suffered serious damageunder the seismic action. Its characteristic is that the first floor collapsed completelywhile the damage of the upper floors is very small, which leads to great loss of lifeand property. The damage of overhead underlying frame structures for large space isparticularly prevalent. Therefore, this article focuses on the studies of the seismicperformance of the first soft layer frame structures. The main work is as follows.(1) In this article, a large number of references and experiment results show thatequivalent bracing model acts well as the infill walls in reinforced concrete framestructure.(2) The value of natural vibration period of the soft first story frame structures hasbeen discussed in detail in this article. In addition, this article has established threekinds of finite element models: net frame structure (model A), infilled wall of allfloors (model B), and infilled wall of all floors except the first floor (model C). Bycomparison of the three models’ period, this article would verify if the periodreduction coefficient of reinforced concrete frame structure,0.6~0.7, can meet thedesign requirements.(3) From the perspective of stiffness transition layer, this article has arrangeddifferent quantity of infilled wall on the second floor and analyzed the maximumhorizontal displacement, inter-story displacement, inter-story drift angle and the totalbase shear with the method of response spectrum and dynamic time history analysis.The result shows that appropriately reducing the amount of infilled wall on thesecond floor can effectively reduce the displacement and inter-story drift angle of thefirst floor, namely it can improve the seismic performance of the reinforced concreteframe with soft first story.(4) Through adjusting the thickness of infilled wall on the second floor, this articlealso has analyzed the maximum horizontal displacement, inter-story displacement,inter-story drift angle and the total base shear of different models with the method ofresponse spectrum and dynamic time history analysis. The thickness of the infilled wall on the second floor is from100mm to250mm. The result shows thatappropriately reducing the thickness of the infilled wall on the second floor caneffectively reduce the displacement and inter-story drift angle of the first floor,namely it can improve the seismic performance of the reinforced concrete frame withsoft first story.(5) Finally, two suggestions have been proposed in this article:①The frame structures should adopt equivalent bracing model to take the effectof infilled wall into consideration.②The architectural engineer and structural engineer should communicate andcooperate closely. On the premise that meeting the requirements of using function,appropriately reducing the quantity or thickness of the infilled wall on the secondfloor can effectively improve the seismic performance of the reinforced concreteframe.