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In this paper, typical characteristics, state of the art and existing problems of intensity measure (IM) parameters are firstly summarized. To consider the contribution of higher modes for the incremental dynamic analysis (IDA) of high-rise structures, an IM parameter in terms of the multiply of power-law functions was proposed, in which response spectra at major periods are the bottom number and corresponding modal mass participation proportions are the exponent. Then IDA of a high-rise SRC frame-RC tube structure was employed to investigate the efficiency of the proposed IM S12 and S123, in which the first two and three modes are considered, respectively. Comparison with PGA, PGV, Sa(T1, ξ), S* proposed by Cordova was made as well. The results show that Sa(T1, ξ) is more efficient than PGA even for high-rise structures. PGV is proven to be efficient relative to the single spectral value Sa(T1, ξ) and measures S* and S12 presented by two spectral values, but deficient relative to the S123 presented by three spectral values. It is found that the more modes are considered, the more efficient the IM is. From the view of engineering application, S123 is recommended for the IDA of high-rise structures. [ABSTRACT FROM AUTHOR]

The research progress on the energy-based seismic design methodology by authors in recent years is presented. Firstly, the relation between energy-based seismic design methodology and traditional seismic design method is discussed. This work points out that a critical condition to realize an energy-based seismic design is that the structure should have a rational damage/energy-dissipation mechanism. Based on this condition, a framework of energy-based seismic design is proposed. Secondly, the energy spectra for energy-based seismic design, including the spectral input energy EI, cumulative hysteresis energy ratio EH/EI for single-degree-of-freedom (SDOF) system, and the relations between energy spectra of SDOF and MDOF systems are briefly introduced. According to the energy spectra, the method to determine the total dissipated energy EH is proposed, which further leads to the method to calculate the dissipated energy EH at the desired positions by using MPA. Therefore, the seismic design of structural elements can be performed based on the elemental dissipated energy EH, the strength demands and the deformation demands. Finally, the application of the proposed energy-based seismic design methodology is demonstrated by the seismic design of a steel braced frame. [ABSTRACT FROM AUTHOR]

Factors affecting seismic base shear and the minimum requirements of seismic base shear for modal response spectrum analysis in the seismic codes of the United States, New Zealand, Canada and Europe were presented. Comparing the factors that were considered in seismic shear factor between the Chinese and American seismic codes and discussion about influence of higher-mode response on seismic base shear of long-period structure, it turns out that seismic shear factor should meet two necessary conditions. Firstly, seismic shear factor associated with the response spectrum shape (determined by site class etc. ). Then, seismic shear factor reflecting the effects of higher-mode and complied with the monotonicity criterion. According to the research report of the SEOAC, the amended seismic shear factor calculation formulae that can avoid the shortcomings of the original one in Chinese 'Code for seismic design of buildings' (GB 50011--2010) was provided. The comparative analysis shows that, the amended seismic shear factor calculation formulae can better reflect the characteristics of seismic base shear and further increase the scope of engineering application. It can provide a reference for the future revision of the seismic code. [ABSTRACT FROM AUTHOR]

The narrower on lower floors and the wider on upper floors structure is used in the National Fitness Center, in Ejin Horo Banner, Inner Mongolia, which has the characteristic of extreme vertical stiffness irregularity. The elastoplastic performance in the condition of static stability limit state becomes the key factors of the security of the structure. First, the performance of the main structure in the condition of static loading was analyzed adopting the performance target put forward in this paper. The choice of the multi-floor structure with the huge grid as the best scheme was made among many schemes. Then the seismic performance studies were conducted by response spectrum analysis, elastic dynamic time-history analysis and elasto-plastic dynamic time-history analysis respectively. The key part of the analysis is the irregularity of the structure, the security at the end of cantilever and the elasto-plastic performance in the condition of major earthquake. Analysis shows that the structural scheme selected based on the performance target put forward in this paper is economic and reasonable, and the static and seismic performance objectives for design are realized. [ABSTRACT FROM AUTHOR]