A SIMPLE METHOD TO CONSIDER STRUCTURAL IRREGULARITIES IN EARTHQUAKE-RESISTANT DESIGN OF STRUCTURES. APPLICATION TO COMPUTING FLOOR ACCELERATIONS FOR THE SEISMIC DESIGN OF DIAPHRAGMS AND NONSTRUCTURAL COMPONENTS
DOI:
https://doi.org/10.18867/ris.111.662Keywords:
earthquake-resistant design, structural irregularities , floor accelerations , diaphragm design , nonstructural componentsAbstract
The 2017 Mexico City Seismic Building Code (MCBC. 2017) and the proposal for the 2023 Mexico City Seismic Building Code (MCBC, 2023) have specific seismic design procedures for considering different structural vertical and horizontal irregularities. The specifications of these norms for defining horizontal seismic floor accelerations are excessively elaborated. The values of these accelerations are needed to determine the design seismic forces in diaphragms and nonstructural components. In the case of irregular structures, the MCBC 2017 specifies elaborated procedures for computing floor accelerations that are pretty different from those set for regular structures and also very different from those specified in the ASCE 7-16 (ASCE 7-16, 2017) and ASCE 7-22 (ASCE 7-22, 2022) for buildings with irregularities.
For buildings with structural vertical and horizontal irregularities, this study proposes that the values of floor acceleration specified for regular structures are amplified depending on the assessment of the structural irregularities of buildings. This procedure was derived from studying the dynamic properties of 23 reinforced concrete buildings with earthquake-resisting systems based on frames or walls. These buildings were designed by Mexican consulting companies who obtained dynamic properties of these buildings. This paper offers simple examples using the proposed penalty factor for considering structural vertical and horizontal irregularities when computing floor accelerations. Results from these examples indicate several convenient features of the proposed design procedure, such as the consistency between the compute results and the expected seismic response of a structure, and because the ratio of seismic masses that uses the proposed procedure is a simple tool for identifying the importance of structural irregularity in a building.
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References
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- 2024-03-20 (2)
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