Seismic isolation of buildings for power stations considering soil-structure interaction effects

Abstract Nowadays, the power industry in Mexico is building encapsulated power stations, because they are a more efficient, safer and cheaper technology for power transformation, and they also require of smaller spaces. Encapsulated power stations have been already built in cities of Mexico where the seismic risk and hazard is negligible. Given all the advantages described above, Comision Federal de Electricidad (CFE), the Mexican power company, is studying the possibility to build this type of station in the Valley of Mexico, where the earthquake risk and hazard are high. Encapsulated power stations are composed of a series of high diameter pressured steel pipes that contain a toxic gas as an insulation media for the electric cables that host inside. Therefore, it is required that for severe earthquake shaking, encapsulated power stations remain fully operational and that there will be no risk of a gas leaks, particularly in the soft soil sites of the Valley of Mexico. The use of base isolation in soft soils such as those found in the lakebed region of Mexico City is atypical and must be seriously evaluated. In soft soils, there is a higher risk of dynamic instability of base isolated structures for severe earthquake shaking due to the likeliness of resonant response with the ground, global rocking effects or sudden differential settlements of the ground. Research studies devoted to assess the feasibility of employing pendular isolation systems for the benchmark architectural model of SF6 power stations for six soft soil sites in the Valley of Mexico are summarized in this paper. Soil-structure interaction (SSI) effects have been included. The results of the study allowed concluding that pendular isolation systems can be used for an effective seismic isolation of SF6 power stations in relatively soft soils.

[1]  Yozo Fujino,et al.  Identification of soil–structure interaction effect in base-isolated bridges from earthquake records , 2001 .

[2]  Arturo Tena-Colunga,et al.  Vulnerability Maps for Reinforced Concrete Structures for Mexico City's Metropolitan Area under a Design Earthquake Scenario , 2007 .

[3]  Douglas A. Foutch,et al.  Seismic retrofit of a RC building: a case study , 1988 .

[4]  G. Auvinet,et al.  The Mexico Earthquake of September 19, 1985—Behavior of Building Foundations in Mexico City , 1988 .

[5]  Arturo Tena-Colunga,et al.  Seismic Design of Base-Isolated Buildings in Mexico. Part 1: Guidelines of a Model Code , 2013 .

[6]  D. A. Foutch,et al.  The Mexico Earthquake of September 19, 1985—Case Studies of Seismic Strengthening for Two Buildings in Mexico City , 1989 .

[7]  Stephen A. Mahin,et al.  A Simple Pendulum Technique for Achieving Seismic Isolation , 1990 .

[8]  D. C. Rizos,et al.  Considering dynamic soil structure interaction (SSI) effects on seismic isolation retrofit efficiency and the importance of natural frequency ratio , 2008 .

[9]  Ioannis Koutromanos,et al.  Seismic response of base-isolated buildings including soil-structure interaction , 2009 .

[10]  Michael C. Constantinou,et al.  Torsional Coupling in Sliding Base‐Isolated Structures , 1993 .

[11]  R. Clough,et al.  Dynamics Of Structures , 1975 .

[12]  Jiahao Lin,et al.  An Introduction to Seismic Isolation , 1993 .

[13]  I. M. Idriss,et al.  Influence of Soil Conditions on Ground Motions During Earthquakes , 1969 .

[14]  Juan Carlos de la Llera,et al.  Torsional balance of plan‐asymmetric structures with frictional dampers: analytical results , 2005 .

[15]  Arturo Tena-Colunga,et al.  International Seismic Zone Tabulation Proposed by the 1997 UBC Code: Observations for Mexico , 1999 .

[16]  Mario Ordaz,et al.  Inslab earthquakes of Central Mexico: Peak ground-motion parameters and response spectra , 2005 .

[17]  Constantine C. Spyrakos,et al.  Seismically isolated bridge piers on shallow soil stratum with soil–structure interaction , 2001 .

[18]  S. K. Thakkar,et al.  Study of Seismic Base Isolation of Bridge Considering Soil Structure Interaction , 1995 .

[19]  Michael C. Constantinou,et al.  Dynamics of Soil-Base-Isolated-Structure Systems , 1988 .

[20]  N. Abrahamson,et al.  Empirical Response Spectral Attenuation Relations for Shallow Crustal Earthquakes , 1997 .

[21]  Juan Carlos de la Llera,et al.  Torsional balance of seismically isolated asymmetric structures , 2013 .

[22]  Luis Eduardo Pérez-Rocha,et al.  Influence of Foundation Flexibility on Rμ and Cμ Factors , 2005 .

[23]  Arturo Tena-Colunga,et al.  Torsional amplifications in asymmetric base-isolated structures , 2007 .

[24]  R. S. Jangid,et al.  Seismic response of isolated bridges with soil-structure interaction , 2003 .

[25]  Arturo Tena-Colunga.  Some Retrofit Options for the Seismic Upgrading of Old Low-Rise School Buildings in Mexico , 1996 .

[26]  Moon Kyum Kim,et al.  Seismic response of base-isolated liquid storage tanks considering fluid-structure-soil interaction in time domain , 2004 .

[27]  Luis Esteva,et al.  The Mexico Earthquake of September 19, 1985—Consequences, Lessons, and Impact on Research and Practice , 1988 .

[28]  R. S. Jangid,et al.  Influence of soil : structure interaction on the response of seismically isolated cable-stayed bridge , 2008 .

[29]  Juan Carlos de la Llera,et al.  Torsional balance of plan‐asymmetric structures with frictional dampers: experimental results , 2006 .

[30]  Mario Ordaz,et al.  Updated Seismic Design Guidelines for Model Building Code of Mexico , 2009 .

[31]  Anil K. Chopra,et al.  Estimating the seismic displacement of friction pendulum isolators based on non‐linear response history analysis , 2004 .