AN ANALYTICAL METHOD FOR SEISMIC VULNERABILITY ANALYSIS OF UNREINFORCED MASONRY BUILDINGS

The damage caused by past earthquakes in Iran indicates that school facilities, in particular masonry schools, are an important part of the built infrastructure that is vulnerable to earthquakes. However, researches focused on seismic loss assessment of masonry buildings in Iran is scarce in the literature (see e.g. Omidvar et al., 2012). As the supplement of a study performed by Azizi-Bondarabadi et al. (2016) to generate empirical fragility curves for Iranian unreinforced masonry (URM) school buildings, the objective of the present paper is to develop a new analytical method for providing validated fragility curves and subsequently performing an economic-based vulnerability assessment. Using the available database of schools in Iran, the empirical method has been developed for four building types from URM schools located in the province of Yazd, Iran. Within the empirical method, the indices of the GNDT II level method (Benedetti & Petrini, 1984) and an index-based method developed in Iran were first evaluated for 25 schools from the four typologies. The results were then correlated to calibrate the GNDT II level method. Then, a procedure was proposed for combining theGNDT II level method and the Macroseismic method (Giovinazzi, 2005) correlating macroseismic intensity I and PGA as well as the physical damage and the damage factor. Finally and using this combination procedure, the calibrated results were employed to derive a relationship for the school typologies that is able to calculate the index V of the Macroseismic method with respect to a simple index Ri of the Iranian method. Among different building types introduced in the empirical method, the analytical method proposed in this paper focuses on the building type M2s (brick walls, horizontal RC ties and RC slabs), which presents a box-type seismic behavior. 25 typical buildings were sampled as representative of the M2s population in terms of building dimensions, structural details and geometric configuration. In the case of mechanical properties, one index building was selected, meaning that the considered buildings has a typical quality class of material with three levels of central, upper bound and lower bound. The structural component model implemented in the TREMURI software (Lagomarsino et al., 2012) was adopted to simulate the 25 school buildings. Pushover analysis was performed to obtain bilinear capacity curves of each of the sampled buildings.

کلیدواژه ها:

Masonry schools. Iran ، Analytical approach ، Vulnerability analysis ، Higher mode effects