| Earthquake disaster is one of the most seriously natural disasters in today's society.With buildings developing towards high-rise and super high-rise structures,among the building structures,the reinforced concrete frame structure where infilled walls serve as the main envelop,also has higher requirements for earthquake resistance.In the Technical Specification of Concrete Structure of High-rise Buildings,the stiffness of the infilled walls is reduced according to the calculation of the vibration period.But in fact,the bearing performance of the whole frame is not consistent with the actual situation after the periodic reduction.Therefore it is essential to further study the frame structure of the infilled walls.The main works of this paper are presented as follows:(1)Test on performance of the building structural material.Included in the test are the compressive strength and the shearing intensity of the sintered shale hollow brick masonry,the compressive strength of the concrete,the tensile strength of the steel bar and the compressive strength of masonry mortar.(2)Experimental research into frame specimens.Operations such as structure design,steel bar binding,concrete pouring and maintenance,and load applying are conducted on the frame specimens to be tested.When the curing time of concrete in frame specimens reaches 28d,low cyclic loading test is carried out.Describe and analyse the phenomenon in the low cyclic loading test.Process the data collected during loading of the test specimen,draw the hysteretic curve of each frame,skeleton curve,ductility factor,strength degradation curve,stiffness degradation curve,and energy dissipation curve.The results show that:The infilled walls enhance the peak load of hysteretic curves and skeleton curves,the maximum load that completely infilled frame test specimen IF can withstand is 2.54 times that of bare frame BF,while the partly-infilled frame specimen IFW,with only 5.8%opening area rate,can at most withstand only 80%load of that of specimen IF.The presence of infilled walls increases the stiffiiess of the specimens,decreases ductility,and accelerates degradation of strength.Before the displacement angle is 1/35,the total energy consumption of specimens IF and IFW per each displacement value,both of which are with infilled walls,is larger than that of bare frame specimen BF.The cumulative energy consumption of specimen IF is 2.83 times of the sample BF,IFW is 2.23 times as much as BF,and IFW is just 0.80 times as less as IF,indicating that the existence of infilled walls increase the energy dissipation of frame structures.However,according to the bare frame ductility is better,BF consumes much more than that of IF and IFW.(3)Numerical simulation analysis of frame specimens.This paper introduces the software OpenSees,and explains the parameters of the restoring force model at the same time.When using software for simulation,infilled walls are treated as two pairs of equivalent diagonal braces,and the stiffness of the infilled walls is assigned by 3:1.The Ibarra-Medina-Krawinkler degradation model is used in the plastic hinge zone.Then for further study carry out the numerical simulation of three specimens of frame specimens,compare with the experimental results the hysteresis curves and skeleton curves of simulation,to verify the accuracy of numerical simulations. |
PDF Full Text Request