Cartilla técnica para el cálculo de fuerzas horizontales y el análisis modal espectral en edificacion

Abstract

This work presents a technical guide for applying the Colombian Seismic Resistance Code (NSR-10) to the calculation of horizontal forces and the execution of modal spectral analysis in buildings. Using a three-story residential structure located in Bogotá as a case study, both manual procedures and SAP2000 modeling were employed to evaluate seismic performance. The results highlight the importance of drift control and the need to adjust structural member dimensions to ensure safety and regulatory compliance. A comparative assessment between the Equivalent Static Method and the Modal Spectral Analysis showed differences of less than 2% in base shear, confirming the consistency of both approaches for regular structures. Additionally, increasing the cross-sectional size of columns improved lateral stiffness, reducing story drifts to within the 1% limit required by the code. The study also considers the updates introduced by Decree 1766 of 2024, which partially modifies NSR-10 while maintaining the applicability of both static and modal analysis procedures for conventional buildings. This document serves as an academic reference and practical tool for civil engineering students and professionals.