Browsing by Author "Jacobsen Pohlenz, Andrés"
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- ItemAn empirical model for preliminary seismic response estimation of free-plan nominally symmetric buildings using ANFIS(ELSEVIER SCI LTD, 2012) Sepúlveda Ovalle, César Raúl; Llera Martin, Juan Carlos de la; Jacobsen Pohlenz, AndrésThe good seismic performance of free-plan buildings during the last M-w = 8.8, February 27, 2010 Chile earthquake, deserves special attention in order to understand the clues for such behavior. Also, and because of economic reasons, the development of these building projects are always subjected to a fast track development, which makes difficult to iterate much on the structural configuration of the building unless quick and reliable responses can be provided to architects and owners. Motivated by these facts, this work proposes a new simplified methodology capable of predicting a reasonably accurate response of free-plan nominally symmetric buildings. Because it is well known that the flexural effect of the slab has a strong influence in the response of these buildings, the methodology is based on the decomposition of the building behavior in two simple extreme cases, zero and infinite flexural stiffness between vertical elements, and horizontal ones. The final building behavior lies in between these cases, and is predicted by producing a linear combination of the models through a single model-parameter a that has been calibrated by using a large training database and an adaptive neural network with a fuzzy inference system, ANFIS. Predicted errors for the displacement and forces of new building configurations are usually less than 10% and 15%, respectively, and in many cases are better than that. Besides its accuracy, the numerical efficiency of this model is usually one to two orders of magnitude larger than that of conventional finite element model of the building. (C) 2011 Elsevier Ltd. All rights reserved.
- ItemPerformance of port facilities in southern Chile during the 27 february 2010 Maule Earthquake(SAGE PUBLICATIONS INC, 2012) Brunet Gutiérrez, Santiago José; Llera Martin, Juan Carlos de la; Jacobsen Pohlenz, Andrés; Miranda, Eduardo; Meza, CristianThis article describes the seismic performance of a group of ports in southern Chile during the 27 February 2010 Maule, Chile, earthquake. Direct costs in damage for these ports have been estimated in slightly less than US$300 million. Similarly to the performance of other ports in previous earthquakes, the most common failures observed were soil related, and include soil liquefaction, lateral spreading, and pile failures. Structural failures were mostly due to short pile effects and natural torsion. This situation is contrasted herein with the performance of the South Coronel Pier, which was seismically isolated in 2007. The isolated portion of this port remained operational after the earthquake, which was the main design goal. Post-earthquake preliminary analyses indicate that the structure was subjected to deformations and forces of approximately 60% to 70% of their design values, respectively. Piles and superstructure remained within elastic range, while the isolators experienced important nonlinear deformations. [DOI: 10.1193/1.4000022]