Seismic evaluation of un-reinforced masonry structures

Abstract

It is well known that masonry buildings suffer a great deal of damage during earthquakes, leading to significant loss of lives. Almost 75% of the fatalities, attributed to earthquake in last century, is caused by collapse of buildings of which the greatest portion (more than 70%)
is due to collapse of masonry buildings. A majority of the tenements in India are Unreinforced Masonry (URM) buildings that are weak and vulnerable even under moderate earthquakes. On the other hand, a cursory glance through the literature on earthquake resistant structures reveals that a bulk of research efforts is on RC structures. Clearly there is a great need to expend more effort in understanding masonry buildings subjected to earthquake induced dynamic loads. The main aim of this thesis is to study the methodology available in literature to evaluate the seismic vulnerability of un-reinforced masonry building using linear/non-linear static and dynamic analyses and to check the applicability of these procedures for seismic evaluation of un-reinforced masonry building through experimental studies. To achieve the above objectives an experimental program has been carried out as part of this
research. Sixteen wall panels of varying dimensions were tested for in-plane monotonic lateral loads. For each specimen a constant axial compressive load was maintained during testing. A window opening at prescribed location of the test specimen was provided for eight of the sixteen specimens and its in-plane monotonic lateral load behaviour was studied. Four additional specimens with a door opening in combination with a window opening were tested for their in-plane monotonic lateral load behaviour.