Comparitive Study On Seimic Design Under Frequent Earthquake And Moderate Earthquake And Seismic Performance Of RC Shear Wall Structures

The theory of performance-based seismic design in China is far from the advanced level in the world.In this paper,the development and present situation of performance-based seismic design in Chinese codes are introduced.Through the comparison of the provisions on performance-based seismic design in Chinese codes,it can be seen that the essence of performance-based seismic design is the design method based on bearing capacity.One of the most important parts is the design of the whole structure or the key components under moderate earthquake.How the structural performance difference between the moderate earthquake design and the frequent earthquake elastic design and,whether the moderate earthquake design can improve the structural performance,there are different views in the engineering field of our country.With the development of performance-based seismic design ideas and methods,these problems need to be solved urgently.Therefore,starting from the current codes of our country,taking RC shear wall structure as the research object,this paper systematically studies the seismic design and seismic performance of the structure using frequent earthquake elastic design method and considering different moderate earthquake design methods.The purpose of this paper is to judge the rationality of the moderate earthquake design of the structure.The main research contents and achievements are as follows:(1)Referring to Code For Seismic Design Of Buildings(GB50011-2010)and Technical Specification For Concrete Structures Of Tall Building(JGJ 3-2010,DBJ 15-92-2013 of Guangdong Province),the elastic design method of frequent earthquake and the design method of moderate earthquake are adopted respectively.48 RC shear wall structures are designed with the height of structures,seismic fortification intensity and site classification,and the designed internal forces of component and the amount of reinforced materials are compared.The variation rules of internal force and reinforcement amount of components are basically the same in the design of moderate earthquake,which are obviously improved compared with the design of frequent earthquake,and the increase of shear force is smaller than that of bending moment in the design of moderate earthquake.The increase of reinforcement quantity of stirrups is less than that of longitudinal reinforcement in the design of moderate earthquake.The design value of moderate earthquake shear force will appear to be smaller than that of the frequent earthquake design for the first and second seismic level of connected beams.The shear capacity of inclined section designed according to the elastic and seismic measures of the frequent earthquake can basically meet the performance target of non-yielding in the moderate earthquake of the connecting beam.(2)The elastoplastic analysis and incremental dynamic analysis of structures considering moderate earthquake design are carried out by using PERFORM-3D software,and the failure modes,performance state distribution and collapse resistance of components are compared.The shear span ratio decreases and the flexural shear ratio increases after considering the moderate earthquake design of some connecting beams and individual shear walls on the second and third floors,which may lead to the shear failure of the components.From the results of incremental dynamic analysis,it can be seen that the moderate earthquake design of the key components is beneficial to improve the anti-collapse reserve capacity of the structure.(3)The damage index calculation method of RC shear wall structure based on component deformation is established,and the damage index is used to evaluate the performance of the structure considering different moderate earthquake design methods.The damage index of the structure designed according to JGJ 3-2010 and DBJ 15-92-2013 of Guangdong Province under moderate earthquake is greater than that of frequent earthquake elastic design structure.Therefore,the design of the whole structure under moderate earthquake reduces the overall performance of the structure.There is no need for the energy dissipation components to do the moderate earthquake design.The existing design method under moderate earthquake is unreasonable.