Masonry Infill RC Frames with Openings: Review of In-plane Lateral Load Behaviour and Modeling Approaches

Abstract

Un-reinforced masonry walls are commonly used as infills in reinforced concrete (RC) buildings. These buildings have high in-plane stiffness and strength, and therefore, the lateral load behaviour of such RC frames is different than that of the frames without infill walls. Openings in walls significantly reduce the lateral strength and stiffness of RC frames, and alter their failure modes. Past researchers have tried to find out experimentally and analytically the influence of several parameters, like opening size and location, aspect ratio of openings, connection between frame and infill wall, ductile detailing in frame members, material properties, failure modes, etc. on behavior of masonry infill RC frames. Accordingly, several analytical models have been proposed in the literature and seismic codes of some countries to model the stiffness and strength properties of infill walls. Most of the past studies and seismic codes recommend modeling the infills as equivalent diagonal struts, and cross-sectional area of the struts are reduced appropriately to account for openings in the walls. Analytical methods have also been proposed to estimate the possible mode of failure and lateral load carrying capacity of infill frames with and without openings. The current article is intended to review and compare past relevant studies and seismic codes of different countries on in-plane lateral load behaviour and modeling approaches for masonry infill RC frames with openings. The comparative study may help designers and code developers in selecting and recommending suitable analytical models for estimating strength, stiffness, failure modes, and other properties of infill RC frames with openings.

Numerically based proposals for the stiffness and strength of masonry infills with openings in reinforced concrete frames

“…A comparison was made in terms of initial stiffness and lateral strength between both models ( Table X). It is considered that these results validate the ability of Equation (16) in predicting the initial stiffness and lateral strength of multi-storey infilled frames with any distribution of openings in the infills. It is considered that these results validate the ability of Equation (16) in predicting the initial stiffness and lateral strength of multi-storey infilled frames with any distribution of openings in the infills.…”

“…Once the stiffness of the solid infill and bare frame are calculated, that is, K fill and K bare , respectively, these parameters can be replaced in Equation (16) for the calculation of the width of the equivalent diagonal strut for each one-bay one-storey frame inside the multi-storey structure. Once the stiffness of the solid infill and bare frame are calculated, that is, K fill and K bare , respectively, these parameters can be replaced in Equation (16) for the calculation of the width of the equivalent diagonal strut for each one-bay one-storey frame inside the multi-storey structure.…”

“…Previous studies have also concentrated on the influence of openings and their position on the inplane behaviour of infilled frames [6,7,11,[13][14][15]. A detailed review of research undertaken regarding masonry-infilled frames with openings was conducted by Surendran et al [16]. Kakaletsis [11] and Asteris et al [17] both concluded that the behaviour of the infilled frames, even in the presence of an opening, can significantly improve the performance of RC frames.…”

Nonlinear seismic responses and lateral force transfer mechanisms of RC frames with different infill configurations

“…This phenomenon has seldom been reported in the literature because most of the quasi-static reverse cyclic tests are displacement controlled with symmetric displacement cycles. Nevertheless, significant asymmetric lateral-load transfer mechanisms of infilled frames with openings have been reported [34,35].…”

Finite Element Analysis for Bearing Capacity of Prefabricated Arch Culverts

“…In such cases, element birth and death techniques could be used to deactivate or reactivate selected elements, respectively [9]. To achieve the "element death" effect, it does not mean that the "killed" elements are actually removed.…”