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Many of the procedures used in bridge design are force-based and may be considered reasonable design approaches that will lead to safe structures. But they do not directly address performance criteria at the initial stage of the design. On the other hand, the previously presented displacement-based design procedures of isolated bridges only considered the displacement of the deck, which means the pier's seismic performance and the substructure mass effects are ignored. This paper presents a new performance-based design method for isolated RC bridges considering the contribution of substructure mass. This method allows the designer that selects the performance level of the superstructure and substructure at the beginning of the design procedure. In this respect, the two degrees of freedom analytical model of the isolated bridge containing substructure mass is presented to quantify its effect on the performance of the seismically isolated bridge. The proposed design method is applied to two continuous-span bridges with regular and irregular substructures, and different target performance levels, including elastic and yielded substructures. The results of the proposed design method have been compared with nonlinear time history analyses, AASHTO, and National Cooperative Highway Research Program simplified methods. The results showed that the seismic performances are close to the results of the nonlinear time history analyses. However, the other design approaches, which ignore the substructure mass, underestimate the responses of the substructure. [ABSTRACT FROM AUTHOR]

In this paper, the process of simulating the occurrence of an earthquake on the fault plane for the 2016 Kumamoto, Japan earthquake is investigated dynamically using finite element methods. The two-dimensional finite element method is used by concentrating friction at the finite points. The used element is the elastic element, whose properties are determined based on the shear wave velocity and longitudinal wave. In order to verify the proposed method, the acceleration and velocity response spectra, Fourier spectrum, and other main parameters of the record obtained from the simulation were compared with the Kik-net data. From the obtained results, the role of displacement and velocity of its application to the fault plate in PGA can be pointed out, so that with a faster displacement of the fault plane, a larger PGA is expected. Friction and shear stiffness between the two fault planes and the dependence of friction on velocity are the main and influential factors in the characteristics of the produced earthquake. In high-frequency earthquakes, friction is dependent on velocity, and when friction is not dependent on velocity, static plays a major role, and no drastic changes in the response spectrum are observed. [ABSTRACT FROM AUTHOR]