Studies On Displacement-pattern-based Seismic Design Method Of Structure

Based on the idea of performance-based seismic design, this dissertation proposes the extant problems of displacement-based seismic design method (DBSD) and presents a research on DBSD methodology for RC frames. The more reasonable approach and specific procedures of DBSD are expected to be established. The main achievements of this dissertation are described as follows:(1) The problems of load-pattern-based nonlinear static analysis (pushover) being pointed out, this dissertation proposes displacement-pattern-based nonlinear static analysis method. This paper indicates that displacement-pattern-based nonlinear static analysis method can conquer the theory inadequacy of load-pattern-based method and is more capable to reflect inelastic behavior. The stability of displacement-pattern is better than load-pattern and this method is easier to obtain structure interstory displacement and element inelastic deformation. By a great number of calculation and comparison, the displacement-pattern of frame structures is analyzed, and the consistent condition and definition method are provided.(2)By studying displacement-pattern-based method, the multi-degree-of-freedom system is equivalent to a single-degree-of-freedom system. The resilience of the single-degree-of-freedom system is obtained by displacement-pattern-based nonlinear static analysis method and the calculation formulas for characteristic parameters of equivalent force- displacement skeleton line are established.(3) The equivalent linearization method is studied and the inelastic system is replaced by elastic system. The relations of equivalent damping ratio and ductility coefficient for equivalent single-degree-of-freedom system is suggested. Based on the equivalent elastic system and displacement spectrum with different damping coefficient, the demand of inelastic displacement under earthquake is determined.(4) The basic steps for displacement-pattern-based seismic design method are provided. A practical example of frame structure is used to validate this methodology, and is compared with the result of time history analysis. The result indicates the suggested method is easy to be used and reliable.