Study On Seismic Behaviors Of Lightweight Wallboard-infilled RC Frames

Lightweight wallboard infill wall has the advantages of light weight,easy installation,and high construction speed.Conforms to our country’s requirements for the development of building industrialization and green building.And until now,lightweight filling wallboard has been widely used in precast and cast-in-situ RC frame structures.However,previous studies on the seismic behavior of infilled frame structures mainly focus on brick and block infilled RC frame structures.And the study of lightweight wallboard-infilled RC frame structure has not been carried out so far.This resulted in the lack of basis for the current seismic design of RC frame structures with lightweight wallboard infill wall.And in practical engineering,it could only be executed according to the rules of masonry infilled RC frame structure.This left hidden dangers to engineering safety.In this paper,the seismic performance of lightweight-wallboard infilled RC frame structure was studied by means of experiment method and theoretical analysis.The main research contents and conclusions were as follows:(1)The cyclic tests on three single story single span RC frame specimens including one bare RC frame specimen CK1,one masonry-infilled RC frame specimen TK1,and one infilled RC frame specimen TK2 with three lightweight wallboard were carried out to study the difference influence on the seismic behaviors of RC frame between block infill wall and lightweight wallboard infill wall.The experimental results showed that: Comparing with masonry infill wall,lightweight wallboard infill wall has a strong lifting effect on the strength and stiffness of RC frame,the ratio of initial stiffness of specimen CK1,TK1,TK2 was 1:1.67:1.75,and the ratio of ultimate strength was 1:1.52:2.03;In addition,the failure mode of lightweight wallboard-infilled RC frames was the collapse of the corners of the wallboard which was a brittle failure,and when the skeleton curve reaches its peak,there will be a sudden drop,besides the ductility coefficient of lightweight wallboard-infilled RC frames was smaller than that of masonry-infilled RC frames.(2)The cyclic tests on infilled RC weak frame specimen TK3 with three lightweight wallboard and infilled RC frame specimen TK4 with four lightweight wallboard was carried out,then comparing wih specimen TK2 to study the effect of the stiffness ratio of frame and filling wall and the width and height ratio of filling wall on the seismic performance of lightweight wallboard-infilled RC frame structure.The experimental results showed that: With the increase of the stiffness ratio of frame and filling wall,the overall failure of lightweight wallboard infill wall of lightweight wallboard-infilled RC frame structure was weakened,and the local failure was strengthened;Besides,the width and height ratio of filling wall has little effect on the stiffness degradation law of the structure,and the effect of filling wall width and height ratio on energy dissipation was not significant,during the entire loading process the cumulative energy dissipation coefficient and relative energy dissipation coefficient of TK2 and TK4 were equivalent.(3)The comprehensive influence ratio l was put forward to evaluate the comprehensive influence of infilled walls on RC frame structure during earthquake.The ratio of comprehensive influence was the ratio of the increase of horizontal resistance of RC frame to the increase of RC frame subjected to earthquake action.Through analysis,it was considered that the filling of lightweight wallboard infill wall and masonry infill wall were beneficial to the seismic performance of RC frame,because the comprehensive impact ratio of infill walls to the RC frame’s seismic performance was bigger than 1.Compared lightweight wallboard and masonry infill walls,in the small earthquake stage,the former was more favorable to the seismic performance of RC frame structure;while in the large earthquake stage,the latter was more favorable to the seismic performance of RC frame structure.(4)Through the analysis of the stiffness degradation law of the lightweight wallboard-infilled RC frames,it was proposed that when lightweight wallboard were used as infill walls,the value of the reduction coefficient of the RC frame structure should be reduced by 0.95 times than the masonry infill wall;finally,seismic structural measures have been proposed for the weak seismic resistance of lightweight wallboard-infilled RC frame.