Publication: ESTUDIO DEL REFORZAMIENTO SÍSMICO DEL PASO SUPERIOR LO ECHEVERS EN SANTIAGO DE CHILE
Date
2019
Authors
ESCOBAR HURTADO, LORENZO ARTURO
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Abstract
Las redes viales son fundamentales tras un evento sísmico, pues permiten el accionar de los diferentes sistemas de respuesta del país ante emergencias o desastres naturales. Sin embargo, es reconocido que los puentes son un elemento vulnerable de la red vial, como se vio reflejado en el terremoto de Maule del 2010, donde de un total de aproximadamente 1.200 puentes de la red vial se reportaron cerca de 300 puentes con daños y una veintena sufrió la caída de sus vanos. Por este motivo, surge la necesidad de aplicar medidas de reparación y reforzamiento sísmico a estructuras existentes, las que producto del pasar de los años pierden parte de su capacidad estructural.En este estudio se comparó la respuesta del Paso Superior Lo Echevers en su condición anterior al terremoto de Maule, en donde sufrió graves daños y el colapso de sus vanos, con la situación posterior a la implementación de medidas de reparación y reforzamiento. Con el objetivo de evaluar las medidas de reparación y reforzamiento sísmico llevadas a cabo en puentes chilenos luego del terremoto de Maule (2010). Las medidas de reforzamiento indicadas por el Ministerio de Obras Públicas de Chile consistieron principalmente en la incorporación de topes sísmicos de hormigón armado, barras sísmicas de acero y diafragmas de hormigón armado, como también aumentos en las longitudes de las mesas de apoyo.Para evaluar la efectividad de las medidas de reparación, se realizaron análisis estáticos no lineales (pushover) y análisis dinámicos no lineales (tiempo-historia), donde en este último análisis se utilizaron registros sísmicos subductivos representativos del territorio nacional. Con la finalidad de evaluar el desempeño sísmico de la estructura, los resultados de cada análisis de la respuesta estructural, fueron comparados con niveles de daño de diferentes componentes críticos del puente.Tras los análisis, se determinó la efectividad de las medidas de reforzamiento en reducir las demandas de desplazamiento en los apoyos elastoméricos. Sin embargo, la inclusión de topes sísmicos de hormigón armado generó un aumento en las demandas de las columnas. Por lo tanto, se hace fundamental disponer de un diseño adecuado tal que permita asegurar la integridad de estos elementos cuando se incorporen topes sísmicos que no actúen como fusibles sísmicos. A pesar de las reducciones en las demandas en los apoyos elastoméricos, aún se esperan daños en la estructura que varían entre moderado a severo.
The highway networks are fundamental after a seismic event since they allow for the rapid response of different systems. However, it is recognized that bridges represent a vulnerable component of the highway networks, as was reflected during the 2010 Maule earthquake, where of the approximately 1.200 bridges in the highway network, about 300 bridges were damaged and about 20 suffered unseating of spans. For this reason, there is a need to apply seismic repair and retrofit measures to existing structures, which as a result of the passing years lose part of their structural capacity.In this study, the seismic response of the Lo Echevers overpass is compared in its condition prior to the Maule earthquake (2010), where it suffered serious damage and the collapse of its spans, with the situation after the implementation of repair and retrofit measures. With the objective of assessing the seismic repair and retrofit measures carried out on Chilean bridges after the Maule earthquake. The retrofit measures indicated by the Chilean Ministry of Public Works (MOP) consisted on adding reinforced concrete seismic stoppers, seismic bars and reinforced concrete diaphragms, as well as increasing seat-lengths.To evaluate the effectiveness of the repair and retrofit measures, non-linear static analyses (pushover) and dynamic nonlinear analyses (time-history) were performed, where subduction seismic records representative of the national territory and damage states of different critical component of the bridge were used to evaluate the behavior of the structure.After the analyzes, it was determined that the repair procedures were effective in reducing displacement demands in the elastomering bearings. However, the inclusion of reinforced concrete seismic stops generated an increase in the demands of the columns. Despite reductions in the demands on elastomeric bearings, moderate to severe damage states are still expected in the structure.
The highway networks are fundamental after a seismic event since they allow for the rapid response of different systems. However, it is recognized that bridges represent a vulnerable component of the highway networks, as was reflected during the 2010 Maule earthquake, where of the approximately 1.200 bridges in the highway network, about 300 bridges were damaged and about 20 suffered unseating of spans. For this reason, there is a need to apply seismic repair and retrofit measures to existing structures, which as a result of the passing years lose part of their structural capacity.In this study, the seismic response of the Lo Echevers overpass is compared in its condition prior to the Maule earthquake (2010), where it suffered serious damage and the collapse of its spans, with the situation after the implementation of repair and retrofit measures. With the objective of assessing the seismic repair and retrofit measures carried out on Chilean bridges after the Maule earthquake. The retrofit measures indicated by the Chilean Ministry of Public Works (MOP) consisted on adding reinforced concrete seismic stoppers, seismic bars and reinforced concrete diaphragms, as well as increasing seat-lengths.To evaluate the effectiveness of the repair and retrofit measures, non-linear static analyses (pushover) and dynamic nonlinear analyses (time-history) were performed, where subduction seismic records representative of the national territory and damage states of different critical component of the bridge were used to evaluate the behavior of the structure.After the analyzes, it was determined that the repair procedures were effective in reducing displacement demands in the elastomering bearings. However, the inclusion of reinforced concrete seismic stops generated an increase in the demands of the columns. Despite reductions in the demands on elastomeric bearings, moderate to severe damage states are still expected in the structure.
Description
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Keywords
ANALISIS NO LINEAL , PASO SUPERIOR LO ECHEVERS , REFORZAMIENTO SISMICO