Study On Calculation Method Of Energy Dissipation Capacity Of RC Members Under Earthquake Action

Earthquake is a terrible natural disaster in the process of human production and social development.China is located at the intersection of two major seismic zones,and earthquake disasters occur frequently.Strong earthquakes have sudden and huge destructive power,which often bring serious harm to social and economic development,human survival safety,social stability and social functions.Therefore,the theoretical research of seismic design is particularly important.Among all the seismic design ideas,the energy-based seismic design idea is clear and concise,which can analyze and reflect the comprehensive influence of seismic amplitude value,spectral characteristics and seismic duration on the building structure.The energy based damage index has a strong advantage in describing the plastic cumulative damage of the structure.In the field of seismic design,energy-based seismic design has been at the forefront of scholars’ research at home and abroad for its theoretical advantages.In this paper,with the support of the National Natural Science Fund(50908022),the energy consumption calculation method of RC members under the condition of variable amplitude hysteresis is studied by using steady-state variable amplitude loading and arbitrary amplitude loading respectively,and the estimation method of energy dissipation capacity decay index of RC members under variable amplitude hysteresis condition is studied.But the data based on this method is limited,and the influence of axial force,shear span ratio,concrete strength and other design parameters on the calculation results is not considered,and the application scope is limited.In order to optimize the theoretical process of damage quantification of reinforced concrete members under earthquake action and establish a reasonable calculation method of energy dissipation capacity,based on the decay law of energy dissipation capacity of RC members in the initial hysteretic stage,and on the basis of studying the DE,k-nk curves shape characteristics of equal loading displacement of the same type of specimens in different hysteretic stages,a decay model of energy dissipation capacity in the subsequent hysteretic stage is proposed.Through the fitting analysis of the attenuation index of different hysteretic stages,the modified formulas of characteristic parameters A,B,x0 and y0 in the calculation method of energy dissipation capacity are proposed;based on the statistical analysis of the semi hysteretic energy dissipation of 34 RC members under continuous variable amplitude loading,the threshold value of the discriminant in the energy dissipation capacity calculation method is adjusted.The results show that the DF,k-nk curves trend of any subsequent hysteretic stage of RC member under steady-state variable amplitude loading mode is determined by the maximum displacement in history and the accumulated dissipated energy,that is to say,the DEk-nk curves of any subsequent hysteretic stage can be obtained by the DE,k-nk curves translation with this hysteretic stage as the initial hysteretic stage.For 22 RC members which are the theoretical support of the proposed method,the energy dissipation capacity calculation method after optimization shows higher accuracy and stability than that before optimization in both process estimation and result estimation;for 80 specimens with various loading modes selected from peer database,the method shows good universal applicability,and the estimation is accurate for small energy dissipation members the characteristics of higher sex.