TECHNICAL-ECONOMIC EVALUATION OF THE USE OF SEISMIC ISOLATION IN A PERUVIAN OFFICE BUILDING

The current Peruvian Seismic Code specifies that hospital buildings, located in most dangerous zones, must be projected as seismically isolated buildings. This requirement has been discussed by Peruvian engineers on whether Seismic Isolation Technology is the unique way to reduce structural and non-structural damage, and if its implementation cost can be justifiable in the building lifetime. The objective is this paper is to evaluate if cost and implementation requirements of seismic isolation technology can be justified with the reduction of expected losses for future seismic events in building lifetime of 50-75 years. This paper evaluates a mid-high-rise office building. This building was proposed in two types of structural system: seismically non-isolated building (RC Structural Wall System); and seismically isolated building (with lead-rubber bearing LRB isolator devices). Both structural systems were designed following Peruvian Seismic Code for seismic analysis, RC Peruvian Code for RC element and ASCE 7 for the design of isolation devices. Nonlinear behavior of RC beam, RC column, RC shear walls and isolation devices were modeled in tridimensional model. Damage states are defined for these elements and related to fragility and consequences curves. Both systems were evaluated to 8 levels of seismic intensity and 20 seismic records for each one, following Incremental Dynamic Analysis and FEMA P-58 methodologies. Expected loss were estimated with PACT program considering all possible local and global damage. Expected Annual Loss is calculated for Seismically isolated and non-isolated building. Then Cost-Benefit was carried comparing the Expected Losses in building lifetime with the implementation cost of this technology. It permitted to evaluate the effectiveness of the seismic isolation system in the building lifetime, considering the probability of occurrence of earthquake of different intensities. Results indicate that implementation cost of Seismic Isolation Technology could be justifiable in the reduction of expected losses in 10 years, and total benefit in building lifetime could be 3 times the implementation cost of this technology.