Evaluación de respuestas y ángulos de incidencia críticos obtenidos por métodos espectrales

critical responses and critical angles for a structure can be obtained by response history analysis (rha) or by response spectrum analysis (rsa). results obtained with rha can be considered as the best approximation available to actual responses, but they require a great amount of numerical effort. results obtained with rsa are more easily obtained, but they have the limitations associated with spectrum analysis. the goal of this investigation is to compare the critical incidence angles and the critical responses obtained with response history analysis (rha) and response spectrum analysis (rsa). the responses are obtained for several one story reinforced concrete structures with linear behavior, viscous damping, and natural periods ranging between 0.1 and 5.0 sec. the analyses are performed for the following two cases: (a) the action of only one horizontal component (the major component), and (b) two horizontal orthogonal components (the major and the minor components). an ensemble of far field ground motions recorded on rock was selected to perform the analyses. the rha results are obtained covering all possible incidence angles for each ground motion. the rsa results are obtained with the critical incidence angle formula given by the cqc3 combination rule, using the mean spectra for the ensemble of the recorded ground motions. the results show that rsa is adequate to estimate the critical responses and corresponding critical incidence angles for design purposes or evaluation of existing structures. more refined values of the critical responses could be obtained using rha in a reduced incidence angle range, given by rsa results, thus reducing the numerical computations required.