These results were presented at the 2nd Asia Conference on Earthquake Engineering "Seismic Hazards and Damage Mitigation in the Asian Region" held in Manila, Philippines from March 10-11, 2006.
For pictures and full details of the findings, please contact Prof Andres Oreta at [email protected]
Title of paper: Basic Structural Performance Index Of Earthquake-Damaged Reinforced Concrete (RC) Buildings (1990 Philippine Earthquake)
Author: Andres Winston C. Oreta
The problem of possible hazards brought about by earthquakes such as building collapse and loss of lives, especially in major urban metropolis like Metro Manila, must be addressed by city planners, building officials and structural engineers. Although our present structural design codes may have incorporated special provisions for the earthquake resistant design of new buildings, there is still a danger for possible collapse or life-threatening damage in existing buildings, especially the old and deteriorated ones. Buildings with large occupancy such as schools and buildings which are essential after an occurrence of an earthquake such as hospitals and other emergency service facilities must be checked urgently on their expected performance against major earthquakes. Civil and structural engineers must address the need of assessing the seismic safety of buildings, possibly for retrofitting or strengthening.
Given the large number of existing buildings in the metropolis, it is clear that detailed seismic inspection and seismic upgrading cannot be advanced simultaneously. A detailed seismic inspection is costly and time-consuming. Seismic strengthening of existing structures is more costly. It is thus important that a brief method of seismic screening of buildings be done to determine which buildings are at greatest risk, and hence must be given priority in detailed evaluation and possible retrofitting.
The seismic screening procedure (level-1) of the Architectural Institute of Japan (AIJ) is one of the rapid approaches of screening existing RC buildings. A modified version of this method was recently applied in the inspection of about 80 important buildings in Metro Manila as part of the on-going Earthquake Impact Reduction Study for Metro Manila (MMEIRS). The AIJ screening procedure is limited to low and medium-rise RC buildings up to six stories and uses a basic structural seismic performance index, Io, which is modified by multiplying factors related to building irregularities, degree of deterioration of strength and ductility, and local geology.