Experimental Study On Seismic Behavior Of Shear Wall Strengthened With High Ductile Concrete

Shear wall,as a kind of main lateral force resisting member,can effectively control the horizontal displacement of structure,and thus has significant effects on its seismic performances.The mechanism properties and dynamic responses of structure system under earthquake action,in which shear walls are adopted as the main members,are mainly depended on the seismic performance of shear walls themselves.As the first earthquake fortification line,shear wall needs to meet the deformation requirements under the small earthquakes,the strength demands under the medium earthquakes,and the ductility requirements under the small earthquakes.The destruction of shear wall in this case is not only difficult to repair,but has a serious threat to human life and property safety.High ductile concrete(HDC)is a new material with high strength,high toughness and high damage tolerance,which also exhibits significant strain hardening and multiple cracking behaviors when subjected to tensile loading.In order to improve the seismic performance of shear wall and reduce the loss caused by earthquake,the shear walls were strengthened by high ductile concrete surface,which can enhance the seismic performance indicators,such as the bearing capacity,deformability,energy dissipation,etc.The contents of this research will be shown as follows.(1)The seismic performances of HDC reinforced shear wall was evaluated in this part.In order to study the influences of HDC layer and steel mash in HDC surface on strengthening effect,3 specimens of shear walls with shear span ratio of 2.1 were designed.According to the quasi-static test,the failure process and the failure mode of specimens were discussed as well as failure mechanism.The seismic performance of specimens was analyzed by the hysteresis curves,skeleton curves,energy dissipation capacity and stiffness degradation.(2)Based on the experimental results,the bending behaviors were evaluated in the condition of cracking,yielding and peak respectively by section fiber model.Besides,the bearing capacities in corresponding state were calculated by combining the constitutive models of materials.Thereby,a suitable capacity analysis method was put forward for HDC reinforced shear wall.(3)The deformations were investigated in such state of cracking,yielding,peak and ultimate respectively,and thus the deformation curve model of simplification was built combining the bearing capacity results.Finally,a quadrilinear recovery force model of shear wall was proposed,by establishing the hysteresis rules and the numerical relations between the damage factor and unloading stiffness.