Influence of a Rocky Soil on the Seismic Performance Level of a Steel Structure Considering the National Construction Code and the Seismic Design Code for the City of Managua

Abstract

The purpose of this study is to determine the seismic performance level of a two-story steel frame, taking into account the definition of rocky soil suggested by the National Construction Code and the Seismic Design Code for the city of Managua. The Capacity Spectrum Method is used to determine seismic performance. This method, which is based on spectral parameters such as displacement and acceleration, overlays the capacity curve of the structure and the seismic demand. The construction of the capacity curve is based on the mechanical properties of the materials used and the cross-sectional areas of the structural elements. On the other hand, the seismic demand curve is constructed using the National Construction Code (RNC-07) and the Seismic Design Code for the city of Managua (NSCM), considering data such as ground acceleration and soil type. The influence of the latter is the focus of this study, as the NSCM proposes spectral adjustment factors based on soil type, meaning that the amplitude of the region corresponding to constant spectral accelerations decreases as soil stiffness increases. This adjustment did not exist in the RNC-07, where the amplitude of this region remained constant between 0.1 s and 0.6 s. Finally, the seismic performance level is determined considering the limits established in Vision 2000: A Framework for Performance-Based Structural Engineering (SEAOC, 1995).