Estimation method of requisite strength to control deformation of RC structure under earthquake motion and investigation of the accuracy

Recently, in earthquake resistant design, there is a tendency to evaluate a building by the performance. One method of the evaluation is to estimate maximum response deformation for a building modeled by single-degree-of-freedom (SDOF) system. In our previous studies, it was confirmed that EIV, which is defined as the intensity of energy input in stationary response, is almost equal to (ΔEmax/Te). (ΔEmax/Te) is the intensity of energy input in earthquake response. In this paper, then, energy absorption model (ES) of building is determined. The Requisite Strength (Py) to control deformation is calculated by solving the relationship, ES = ED (Total Input Energy). In order to calculate the Py to control maximum deformation, it is necessary to estimate the non-linear cyclic number (ND), ED and Maximum Deformation Ratio coefficient (MDR). ED and ND are estimated from elastic response analysis in 5% damping corresponding to changed period by structure's plasticity and MDR is estimated by maximum ductility factor and energy absorption capacity coefficient (ζ). Inelastic response analysis for SDOF is carried out to investigate the accuracy on estimated Py by the proposed model. As a conclusion of these investigations, it is shown that the assumption on modeling of energy absorption is generally valid. And the accuracy of calculating Py (that is accuracy of estimated ED, ND and MDR) is almost high. For further improvement of the accuracy, it is important to estimate accurately the MDR, particularly in the case of JMAKOBE which caused strong one side plastic deformation.