Fastener-based Computational Models for Prediction of Seismic Behavior of Cfs Shear Walls

A common lateral force resisting system for cold-formed steel (CFS) buildings consists of shear walls sheathed with oriented strand board (OSB). Previous experimental and computational research on CFS shear walls, as well as those with other framing materials, has demonstrated that the complex interaction of the fasteners with the sheathing is an important factor in the nonlinear behavior of the shear wall. The research described in this paper develops and validates fastener-based computational models of CFS shear walls. The basic computational model in OpenSees consists of beam-column elements for the CFS framing and a rigid diaphragm for the sheathing. The framing and sheathing are connected with zero-length, non-linear fastener elements in which the non-linearity captures the sheathing material damage in the area surrounding the fastener. Fastener properties are determined based on independent testing of fastener groups. Shear wall widths of 4 ft, 8 ft and 12 ft were studied, considering various methods of modeling the hold-downs, shear anchors, sheathing seams and ledger track. The computational results are validated against full-scale tests of similar shear walls. The results indicate that this type of model can accurately represent the initial stiffness, strength and nonlinear behavior of CFS shear walls. Associate Professor, Dept. of Civil and Environmental Engineering, Bucknell University, Lewisburg, PA 17837. [email protected]. Undergraduate Research Assistant, Dept. of Civil and Environmental Engineering, Bucknell University, Lewisburg, PA 17837. Professor, Dept. of Civil Engineering, Johns Hopkins University, Baltimore, MD 21218-2682. Buonopane SG, Tun TH, Schafer BW. Fastener-based computational models for prediction of seismic behavior of CFS shear walls. Proceedings of the 10th National Conference in Earthquake Engineering, Earthquake Engineering Research Institute, Anchorage, AK, 2014. DOI: 10.4231/D3ZW18S94 Fastener-based computational models for prediction of seismic behavior of CFS shear walls S.G. Buonopane, T.H. Tun, B.W. Schafer