Spectral analysis of Al Haouz earthquake and comparison with the design spectrum

Al Haouz earthquake damage highlights the insufficiency of the current normative spectrum. Spectral amplitude comparison against the local records shows that the spectral amplitudes, in certain periods ranges, were greater than RPS 2011 predictions, particularly for the case of medium-height RC buildings. This underestimation of seismic load highlights the necessity to update the design spectrum such that the seismic risk level in Morocco will be better addressed. This revision would render new constructions safer and improve ways of assessing and restoring existing structures. The study is based on the accelerogram of Al Haouz earthquake (Mw = 6.8) and aims to investigate the spectral parameters of the motion with the view of assessing its importance to buildings, according to which comparison was made with Moroccan earthquake laws requirements (RPS 2011). Elastic response spectra were calculated for 5% damping and, additionally, compared with normative spectrum for the different soil categories. The results present large spectral peaks for the period intervals 0.4-0.8 s, typically associated with the medium-height reinforced concrete structures. The result confirms a possible underestimation, by the normative spectrum, of seismic effects for certain range intervals of periods