Resumo

BOJORQUEZ MORA, Edén et al. Una medida de intensidad sísmica basada en un parámetro para caracterizar la forma espectral denominado N_p. Ing. sísm [online]. 2012, n.86, pp.01-26. ISSN 0185-092X.

Several spectral-shape based ground motion intensity measures (IMs) are analyzed. Firstly, a new vector-valued IM based on the spectral acceleration at first mode of vibration Sa(T₁), and a parameter proxy for the spectral shape named N_p is introduced. The efficiency of the vector <Sa(T₁), N_p> is compared with other IMs by dynamic analysis of single degree of freedom (SDOF), reinforced concrete and steel frames. The structures are subjected to ground motion records with different characteristics (including near-fault and narrow-band motions). It is shown that the vector here proposed has better relation with maximum and energy demands, reducing the uncertainties associated with the structural response, which is fundamental piece in record selection for nonlinear dynamic analysis, and for structural reliability assessment. Finally, a scalar intensity measure based on Sa(T₁) and N_p is analyzed, and it is illustrated the possibility to compute seismic hazard analysis for the new scalar parameter with tool currently available.

Palavras-chave : ductile braced frames; chevron steel bracing; capacity design; design drifts; overstrength factor; structural performance.