Comparación del diseño por capacidad entre el enfoque global y el enfoque local de una estructura de acero formado por pórticos especiales resistentes a momento

Abstract

Capacity design is widely used in seismic forces resistant structures design where nonlinear analyzes are not required. An elastic model of a structure formed by steel special moment frames is made using the Etabs software. Geometric characteristics and applied loads were taken from FEMA P-695. Serviceability design is carried out by two methods: Equivalent Lateral Force and Modal Spectral Analysis. We analyze two design approaches applied to capacity design. In global approach, an overstrength factor is used for columns and connections design, beams are designed without overstrength factor in order to ensure that the structure response to the earthquake cyclical loads develops the beam mechanism, as required by the Standard. In local approach, the overstrength factor is not used, columns and connections are designed with the maximum capacity developed in the plastic hinges projected on the face of the column, in order for the beam mechanism to develop, i.e., is an element-by-element design. Finally, a capacity design guide is presented applying the global and local approaches.