Análisis técnico económico del coeficiente de reducción de respuesta estructural con aplicación y comparación en sistemas aporticados de estructuras metálicas

Abstract

In this degree work, the analysis and calculation of the seismic reduction factor for a structure with special moment frames (PEM or SMF) composed of four different mathematical models where the seismic reduction factor changes with values of R=8, 6, 4, 5 and 3. 5 and 3; performing the dynamic linear structural analysis of the four models, each structure changes according to the demand required by the seismic forces, determining that the lower the value of R the larger sections are required in the structure, in spite of the above, the fundamental vibration period of the structures was maintained for R= 8, 6 and 4. 5, while for the factor R=3 the period is slightly reduced resulting in a stiffer structure, as the seismic response factor is reduced, more robust sections are required to provide more weight to the structure to meet the demand. An economic analysis was performed with the sections obtained, which shows that the lower the R value, the structure requires a higher weight and therefore influences a higher cost, so the structure with the lowest cost is the structure with an R=8. Additionally, a pseudo-static non-linear analysis was determined to determine the structural performance of each of the four models using the ATC-40 and FEMA- 440 methods, highlighting that the models maintain the same architectural and geometric configuration but with different sections in certain elements that required a higher geometry as the R value decreases, after obtaining the results of the static non-linear analysis, the performance point was determined using the ASCE 41-17 and FEMA 440 (2005) methodology, resulting in the R=8, 6, 4. 5 and 3 for 475 years has a performance level in X and Y of immediate occupancy. For the determination of the structural response factor, the methodology proposed by Dr. Aguiar 2006 was followed, which is similar to that of ATC-19 (1995), where the ductility, resistance and redundancy factor is determined, data that are collected from the performance point obtained for the elastic design spectrum with a return period of 475 years, the structural response factors R obtained establish that the average range is between 6 and 7.5, on the other hand the structure that presents greater capacity and performance is the one that was designed with R=4. 5 so having extremely rigid sections does not guarantee stability and ductility in a structure, finally a high level of performance (immediate occupation) and seismic energy dissipation capacity is established in the structure designed with a R=6 where its value is similar and slightly lower than 4.5, so it is concluded that for a structure of special steel composite moment frames a design with a structural response factor equal to 6 should be sought.