1 A NEW METHODOLOGY FOR VULNERABILITY ASSESSMENT OF SLENDER MASONRY STRUCTURES Manjip SHAKYA 1 , Humberto VARUM 2 , Romeu VICENTE 3 and Aníbal COSTA 4 ABSTRACT Slender masonry structures such as towers, minarets, chimneys and Pagoda temples can be characterized by their distinguished architectural characteristics, age of construction and original function, but their comparable geometric and structural ratios yield to the definition of an autonomous structural type. These structures are distributed all over the world and constitute a part of the architectural and cultural heritage. Their protection against earthquakes is of great importance. This concern arises from the strong damage or complete loss suffered by these structures during past earthquake. Seismic vulnerability assessment is an issue of most importance at present time and is a concept widely used in works related to the protection of buildings. Seismic vulnerability represents the amount of damage that could be present in a building as a consequence of the occurrence of an earthquake of certain intensity. However, there is few research work carried out on developing the seismic vulnerability assessment tools for such structures. This paper presents a simplified method for assessing the seismic vulnerability of slender masonry structures based on vulnerability index evaluation method. The calculated vulnerability index can then be used to estimate structural damage after a specified intensity of a seismic event. Here, 12 parameters (qualitative and quantitative) are defined to evaluate the vulnerability index for slender masonry structures. Nonlinear parametric analysis is carried out to calibrate most of the quantitative parameters, as well as to define weight of each parameter. Implementation of this methodology is carried out in different types of slender masonry structures to develop vulnerability curves for these structure types. INTRODUCTION Slender masonry structures are featured by their notable slenderness and also represent one of the main differences from most of the historic structures or ordinary buildings. These structures are able to resist gravitational actions, but as they were not explicitly designed to withstand seismic loading, show particularly weakness with regard to horizontal loadings induced by a strong motion. The limited ductility of the masonry combined the slenderness of theses tower, that behave as a vertical cantilever fixed at the base, generally provides a rather brittle structural behaviour. Therefore these constructions are particularly vulnerable with respect to seismic action. The historical slender masonry construction, have demonstrated during the past to be susceptible to damage, and prone to partial or total collapse, under earthquake actions, sometimes due to inadequate retrofit or lack of it (Russo et al., 2010). In Italy, the sudden collapse of the Pavia civic 1 PhD Student, University of Aveiro, Aveiro, Portugal, manjip.shakya@ua.pt 2 Associate Professor with Habilitation, University of Aveiro, Aveiro, Portugal, hvarum@ua.pt 3 Assistant Professor, University of Aveiro, Aveiro, Portugal, romvic@ua.pt 4 Full Professor, University of Aveiro, Aveiro, Portugal, agc@ua.pt