El-Dakhakhni[1] , M. Elgaaly[2] , and A. Hamid[3]

  1. Research Assistant, Department of Civil and Architectural Engineering, Drexel University, Philadelphia, PA, 19104, USA. E-mail : wwe22@drexel.edu
  2. Professor, Department of Civil and Architectural Engineering, Drexel University, Philadelphia, PA, 19104, USA. E-mail : elgaalym@drexel.edu
  3. Professor, Department of Civil and Architectural Engineering, Drexel University, Philadelphia, PA, 19104, USA. E-mail : hamidaa@drexel.edu

ABSTRACT

Masonry infilled panels in framed structures have been long known to affect strength, stiffness and ductility of the composite structure. In seismic areas, however, ignoring the composite action is not always on the safe side, since the interaction between the panel and the frame under lateral loads dramatically changes the stiffness and the dynamic characteristics of the composite structure and hence its response to seismic loads. This study presents a simple practical method of estimating the stiffness and the lateral load capacity of concrete masonry-infilled steel frames (CMISF) failing in corner crushing (CC) mode, as well as the internal forces in the steel frame members using finite element method (FEM) analysis.

In this method, each masonry panel is replaced by three struts with force-deformation characteristics based on the orthotropic behavior of the masonry infill. A simplified steel frame model is also presented based on the documented modes of failure of CMISF. The method can be easily computerized and included in the analysis and design of threedimensional CMISF structures. The proposed technique accounts for the non-linear behavior that occur in the steel frame due to formation of plastic hinges, and in the masonry panel due to crushing. It has been demonstrated that the proposed model can predict both the stiffness and the ultimate lateral load capacity of such systems.

Key Words: Concrete Masonry, FEM Modeling, Infilled Steel Frames, Orthotropic Masonry, Three Strut Model.

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