Modélisation par macroéléments de bâtiments en maçonnerie non-armée pour analyse de fragilité

Abstract

Unreinforced masonry buildings (MNA) are very vulnerable to seismic solicitations since they were built before seismic codes were established. Many buildings in East Canada are made of MNA: stones or bricks. The lack of data about mechanical properties of this type of constructions make it complicated to evaluate the seismic vulnerability. The aim of this study is to develop a process to evaluate the seismic vulnerability of MNA constructions. To do so, the lateral resistance of these buildings is to be evaluated, the curves of fragility are established then to end up with an estimation of economic losses. In this study, prototypes were selected among the existing buildings in Old Québec and Montréal: one prototype made of stones for Quebec City and one made of bricks for Montreal. The selection was from existing inventory. These prototypes are modeled in 3D using the macro-element approach. In the macro-element approach, the structure is considered as an assembly of a wall elements (pillars, spandrel…) which have a plane behaviour defined by bending, shearing and diagonal traction. The modeling and the non-linear static analysis of the prototypes were performed using the software 3Muri©, which allows to define the capacity model of the building, i.e.: its lateral resistance according to the displacement. The material mechanical proprieties used in modeling with 3Muri© are taken from laboratory tests results in past research projects. The outputs are afterwards compared to the results obtained with the equations of prediction of lateral resistance and characteristic displacements. A parametric analysis is performed finally to obtain a model of median capacity taking into consideration the variability of geometrical and mechanical proprieties of the prototypes. A process was developed to generate fragility curves with log-normal distribution taking into consideration the degree of damage, in terms of displacement, issued from the results of modeling. Different approaches of fragility were used: “Euler” for Europe, “Hazus” for US and the parameters from this study. A comparison between these approaches showed that “Hazus” underestimates the damage comparing to the estimation issued from this work, whereas, “Euler” is more conservative with more estimated damage. For MNA brick building in Montreal, the effect of the roof type, mansard or false mansard, and the localisation: isolated or in a row of buildings, are also considered.

Date	18 Oct 2019
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Marie-José Nollet (Supervisor) & Amar Khaled (Co-supervisor)