Proposed multi-strut macro models for structural analysis of RC infilled frames under lateral loads

Resumo

There is knowledge of contribution to the gain of lateral stiffness and stresses distribution in structural
elements provided by infill walls in RC framed structures. The non-inclusion of masonry infills in structural

model not always leads to structural safety positively. The redistribution of internal forces caused by frame-
masonry interaction may submit the structural elements to high stresses not predicted in design. One of the

factors for not considering the masonry infill walls in the structural model is the complex behavior of the panel-
frame and the dependence of several mechanical and geometric variables of the frame structure and masonry. A

simple macro model to simulate the contribution of the infill walls is by an equivalent single strut. This macro
model is unable to capture properly the local effects caused by the interaction between infills with columns and
beams. In this case, there is the need of macro model with multiple struts. The paper intends to compare the
internal forces in columns (shear forces and bending moments) and lateral stiffness in masonry-infilled RC
frames obtained from proposed multi-strut macro models. These results are compared with ones obtained from a
more accurate model developed by FEM capable to take into account the friction effect and slipping between
masonry and frame members.