Study On Ground Montion Selection Method Based On Power Spectrum And Distribution Of Structural Dissipated Energy

In recent years, a few catastrophic earthquakes have made a number of buildings ruined, and how to prevent such earthquakes that beyond the region seismic precautionary intensity challenges the structural design and analysis. In addition to force-based analysis method, energy-based analysis method may also be a way to solve this kind of problem, while the distribution of structural dissipated energy(DE) is the key problem of this method.This paper is aimed at achieving the structural element DE demand, and does some work on the RHI spectrum of SDOF system, modeling the real structure, ground motion selection method fitted for energy analysis, and distribution rules of structural DE. The main jobs and conclusions are listed below:(1) Code an energy computing program named PERA, and analyze the influence factors on RHI spectrum of SDOF system as the object of research. From the result of analysis, the damping model affects RHI spectrum a lot, ductility factor is a major contributor to RHI spectrum, and the frequency content infects RHI spectrum less for short-period structures.(2) Based on the designed 5-storey RC frame structure as an example, with comparing with results computed by the other two finite element analysis programs, the reliability of CANNY modeling is verified. In addition, the related parameters for nonlinear analysis are defined.(3) The control effect of the Two Frequency Domain(TFD) ground motion selection method on the discreteness of structural total input energy is investigated based on energy analysis of the structure under earthquake action, and the relationship between structural total input energy and spectral characteristics of power spectrum near the natural frequency of the structure is analyzed and validated. Build up a kind of record selection method based on power spectrum. By comparing the control effect of this paper's method on total input energy, it's verified that the ground motion selection method based on power spectrum is more statistical for the energy analysis, which demonstrates that it's a rational method for the selection of ground motions.(4) The division of total input energy is investigated based on the seismic energy response analysis. Through analyzing apportion of total input energy between total strain energy and damping energy, it's proposed to compute total strain energy by the product of total input energy and RHI. Meanwhile, the fitted equation of total input energy and mean line of RHI are separately given.(5) The distribution in vertical and transverse direction of beam and column energy dissipation is evaluated. The study concludes that beam contributes a larger portion of DE than column; the distribution of beam DE along the height is in modified exponential distribution and column DE in Rayleigh distribution; in transverse, the ratio of mid-frame to side-frame for beam DE and column DE are different in each storey. The calculation formula of total beam and column DE, plus the fitted equation formula of distribution factor along storeys of beam and column DE, is proposed, and the proposed the ratios of mid-frame to side-frame for beam DE and column DE together with the ratios of side-beam to mid-beam DE as well as the ratio of side-column to mid-column DE of each storey are given. Furthermore, the consistency between structural damage pattern and the distribution of DE is validated through the distribution of plastic hinges.