Fragility Analysis of Existing Unreinforced Masonry Buildings through a Numerical-based Methodology

Amin Karbassi,Pierino Lestuzzi

doi:10.2174/1874149501206010121

Abstract

As an approach to the problem of seismic vulnerability evaluation of existing buildings using the predicted vul-nerability method, numerical models can be applied to define fragility curves of typical buildings which represent building classes. These curves can be then combined with the seismic hazard to calculate the seismic risk for a building class (or individual buildings). For some buildings types, mainly the unreinforced masonry structures, such fragility analysis is complicated and time consuming if a Finite Element-based method is used. The FEM model has to represent the structural geometry and relationships between different structural elements through element connectivity. Moreover, the FEM can face major challenges to represent large displacements and separations for progressive collapse simulations. Therefore, the Applied Element Method which combines the advantages of FEM with that of the Discrete Element Method in terms of accurately modelling a deformable continuum of discrete materials is used in this paper to perform the fragility analysis for unreinforced masonry buildings. To this end, a series of nonlinear dynamic analyses using the AEM has been per-formed for two unreinforced masonry buildings (a 6-storey stone masonry and a 4-storey brick masonry) using more than 50 ground motion records. Both in-plane and out-of-plane failure have been considered in the damage analysis. The dis-tribution of the structural responses and inter-storey drifts are used to develop spectral-based fragility curves for the five European Macroseismic Scale damage grades.

Highlights

For regions where little damage data exist, small scale experimental tests and numerical modelling methods are good substitutes for the observed damage procedures in the process of the seismic vulnerability evaluation for existing buildings such as unreinforced masonry buildings
The Applied Element Method which combines the advantages of FEM with that of the Discrete Element Method in terms of accurately modelling a deformable continuum of discrete materials is used in this paper to perform the fragility analysis for unreinforced masonry buildings
The objective of this paper is to present a numerical-based methodology to develop fragility curves for unreinforced masonry buildings

Summary

Introduction

For regions where little damage data exist, small scale experimental tests and numerical modelling methods are good substitutes for the observed damage procedures in the process of the seismic vulnerability evaluation for existing buildings such as unreinforced masonry buildings. [3,4]) to more complex dynamic methods (e.g., [5,6]) are conducted to study the seismic vulnerability of existing buildings. Simple procedures have been proposed to study the nonlinear dynamic behavior of masonry building [7]. In the interest of achieving a simpler model for dynamic analysis, the model developed is based on two-dimensional behavior only. Three-dimensional analysis should produce a more accurate description of the behavior of the structure during an earthquake

Objectives

Results

Conclusion