Effect of openings on lateral stiffness and strength of confined masonry walls

Confined masonry construction is made up of masonry walls and confining ties, which are built on all four sides of each wall. This system is a conventional form of house construction, as well as a good alternative for post-disaster reconstruction of seismically damaged and/or collapsed buildings in many countries. Window and door openings appear in many panels of confined masonry buildings, but many codes do not consider the effect of these openings in the strength and stiffness of confined masonry panels. In this study, the influence of masonry panel openings on the stiffness and strength of confined masonry walls is investigated. A finite element program, DIANA, is used for the finite element modeling of fully grouted confined masonry walls, walls with unfilled head joints, two-story walls, walls with a lintel band and walls with added vertical ties on the opening sides. All specimens have openings and are constructed according to the Iranian seismic code (Standard No. 2800-05). Models are validated by the results of the tests performed on two fully grouted one-story one-bay confined masonry walls, and a two-story one-bay confined masonry wall, constructed in Iran. Simple equations are proposed that predict the effect of central openings on the stiffness of different types of confined masonry wall and the cracking strength of fully grouted walls with openings. (C) 2014 Sharif University of Technology. All rights reserved.