Quantification of seismic exposure and vulnerability of historic buildings in Metro Manila

Structures such as buildings are at risk to the natural hazards such as earthquakes. Damage and loss of these structures may cause not just human lives but cultural heritage to be lost as well. This study aims to look into the exposure and vulnerability that deal with how many historic buildings there are in Metro Manila, how they are classified and how susceptible these buildings are to damage because of a certain amount of ground motion.

Inventories for exposure were conducted according to structural material, height and vintage. The building typologies of HAZARDS US Multi-hazard and UPD Institute of Civil Engineering were used and modified in this study. Three buildings, specifically the Central United Methodist Church (CUMC), Ellinwood Malate Church and Ermita Church, were modeled and analyzed with the aid of ETABS. Using the performance points and capacity curves derived from the nonlinear analysis, vulnerability was quantified by coming up with a vulnerability curve that expresses damage as a function of ground motion.

It was concluded that there are 54 historic buildings present in Metro Manila as of 2012. Reinforced concrete moment frames comprised the majority of historic buildings at 44.5 per cent of the population. Among the three buildings, CUMC responded as the strongest and Ermita Church responded as the weakest.

This paper fulfils the need to quantify the seismic exposure and vulnerability of the historic buildings in Metro Manila, as the more vulnerable these structures are, the more they need to be strengthened against potential hazards.