Evaluación de vulnerabilidad sísmica de edificaciones de estructuras metálicas en la parroquia Huachi Grande, Ambato, Ecuador: propuesta de reforzamiento estructural de una edificación representativa

Abstract

The district of Huachi Grande is part of the rural area of the city of Ambato; however, in recent years it has shown an important economic development not only through agricultural activities, but also through the industrial sector. The objective of this research work was to analyze the seismic vulnerability of metal structure buildings in the district and to evaluate in detail the vulnerability of one of the most representative buildings in order to design a reinforcement proposal. Methods such as rapid visual inspection using the forms established in FEMA P-154, NEC 15 and FUNVISIS were used. It was found that the vulnerability of the buildings in the district was high in the majority of cases. For this reason, an industrial building with a mixed system of hotrolled steel portal frames and cold-rolled steel trusses was selected; the building presented pathologies derived from conceptual errors in the design and assembly of the structure. A detailed vulnerability analysis was performed on the selected building through the linear static and spectral modal method; the limits of floor drifts, basal shear and deflections were checked. It was found that the building does not comply with the load solicitations established by NEC 15; therefore, it was necessary to propose a reinforcement system. The most relevant pathologies were local and lateral buckling of the main and secondary elements. The strengthening strategy included the addition of elements in the columns to form compact elements and also the replacement of secondary elements with more efficient sections. Additional failures were identified such as the inadequate location of tension elements in the trusses and the need to locate San Andres cross members. The reinforcement will allow the building to perform better under service and seismic loads.