Experimental Research On The Performance Of Concrete Core Wall Under Biaxially Cyclic Loadings

High-rise steel frame-reinforced concrete core wall hybrid structures has becomeone of the main structural forms of high-rise buildings in China. Reinforced concretecore wall is important component in the system of steel frame-reinforced concretecore wall structure, the space stress, which has a great deal of resistance to lateralstiffness and bearing capacity in the horizontal direction, to become the main keycomponents to resist lateral force in this kind of system under wind load and seismicaction level, be regarded as this kind of structure seismic fortification of the first lineof defense. As a result, the performance of concrete core wall under the action oflateral force, the entire structure is directly related to the performance of the system.However, there are less research in reinforced concrete core wall as the object of thebidirectional loads at home and abroad. To advance this aspect of the work, on thebasis of existing research, a large scaled specimen of concrete core wall, subjected tohorizontally single and biaxial loadings, is tested quasi-statically, which using moreheight to width ratio and axial compression ratio and had a greater influence on thechoice of component performance loading rules, to study its failure pattern, bearingcapacity, the performance of the hysteretic characteristics, distortion, etc.The test results show that:1、Under the same axial compression ratio, the final failure pattern of theconcrete core wall subjected to horizontally single and biaxial loadings are overallbending failure. Under horizontally single loadings, the oblique shear crack of theweb coupling wall-column is serious, even the coupling beam’s damage is serious;Lower flange wall horizontal crack is more, the upper is lighter. Under the biaxialloadings, two direction coupling wall-column alternative as web wall or flange wall,cracks are intertwined, and the concrete damage in the root corner wall is serious, thefinal crushing.2、Under the same bidirectional loading rules, the final failure pattern of theconcrete core wall subjected to different axial compression ratio within the scope ofthe test are overall the concrete crushing (corner is serious) after the tensile bar yieldwhich is at the bottom of the coupling wall-column. The specimen with low axialcompression ratio crack early, its shear fracture develop obviously, the two directioncracks are intertwined very sufficiently. The specimen with high axial compressionratio’s wall limb fracture mainly concentrated in the bottom three layers, the root ofthe concrete wall crushing soon.3、The concrete wall under horizontal biaxial loadings has stable energydissipation in each direction, but the coupling effect leads to structural bearingcapacity and deformation properties is poorer relative to horizontally single loadings. 4、Under horizontal biaxial loadings, the specimen with high axial compressionratio within the scope of the test, the competition can improve the bearing capacity ofstructure, but leading to poor deformation performance in two directions, unfavorableto seismic performance of the concrete wall.5、At horizontal biaxial specimen, under the same displacement amplitudes, thehysteretic energy dissipation of each one-way is greater than single load specimen, thetotal energy consumption in two direction is about three times of single loadspecimen.6、 Under horizontal biaxial loadings, the specimen with different axialcompression ratio has not the average compression of wall on both sides of thecoupling beam, the coupling wall-column’s tension angle is greater than the presureangle.Through finite element software ABAQUS for the concrete wall specimen issimulated, the finite element calculation results is fit for the test results, shows that theestablished finite element model is more reasonable, providing the reference for thetheoretical research and engineering application.