Proposed macro-model for the analysis of infilled frame structures

Abstract

Reinforced concrete frames infilled with masonry panels constitute an important part of the high-risk structures in different regions of high seismicity. In some developing countries, they are still used as main structural system for low to medium rise buildings. Consequently, reliable methods to analyse infilled frames are required in order to reduce the loss of life and property associated with a possible structural failure.
 The equivalent strut model, proposed in the 1960s, is a simple procedure to represent the effect of the masonry panel. Several improvements of the original model have been proposed, as a result of a better understanding of the behaviour of these structures and the development of computer software. This paper presents a new macro-model for the evaluation of the global response of the structure, which is based on a multi-strut formulation,. The model, implemented as 4-node panel element, accounts separately for the compressive and shear behaviour of masonry using a double truss mechanism and a shear spring in each direction. The principal premises in the development of the model are the rational consideration of the particular characteristics of masonry and the adequate representation of the hysteretic response. Furthermore, the model is able to represent different modes of failure in shear observed for masonry infills. The comparison of analytical results with experimental data showed that the proposed model, with a proper calibration, is able to represent adequately the in-plane response of infilled frames.

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

“…Three different types of strut model have been proposed to simulate the behaviour of infilled frames: single strut, double strut, and triple strut [24,25]. Experiments on masonry infill panels have also revealed that the equivalent strut must have a representative width in order to accurately represent the infill.…”

Recent Findings and Open Issues concerning the Seismic Behaviour of Masonry Infill Walls in RC Buildings

“…Later, Crisafulli and Carr [152] proposed an improved strut model to compute the behaviour of infilled frame systems. For that, it was presented an integration of struts and spring to computing independently two phenomena: (i) diagonal cracking and corner crushing and (ii) shear sliding.…”

Nonlinear seismic analysis of masonry infilled RC frame structures

“…A number of researchers (Chrysostomou et el. [7], [8], Crisafulli [9] El-Dakhkhni et al [10], [11], [12], Crisafulli and Carr [13], Rodrigues et al [14], [15], Mihaleva [6] et al) modified firstly proposed single diagonal using few diagonals gathered in one model. As a result of this the contact zones and interface surfaces are more precisely modelled especially opening the tensile surfaces located at the edge.…”