Performance Of Centre Sheathed Cold Formed Steel Framed Shear Walls Phase 2 PDF Download

"The use of cold-formed steel (CFS) for seismic force-resisting systems (SFRS), including shear walls, has increased throughout the years. However, the design provisions for CFS sheathed and framed shear walls available in the North American CFS standards (AISI S400 and AISI S240) are limited by the shear walls' sheathing and framing thicknesses. Design guidelines for CFS sheathed and framed shear walls for the purpose of mid-rise construction (up to 5 storeys) are still absent from the standards. The main objective of this research program was to develop a design procedure for CFS sheathed and framed shear walls to achieve higher capacity and ductility to resist the higher forces experienced in mid-rise construction. The developed design procedure is proposed to be included in the provisions of the AISI S240 Standard and AISI S400 Standard.The design procedure was developed by determining the shear strength of full-scale shear wall specimens built and tested at McGill University under monotonic and cyclic loading protocols. A total of 31 specimens, with varying building parameters, were constructed using thicker sheathing and framing members than what is currently available for design. The specimens were built using two new shear wall configurations (double-sheathed and centre-sheathed) to address out-of-plane forces experienced by shear walls tested in previous research programs.The centre-sheathed shear wall configuration, with a confined and concentrically placed sheathing panel, reached a shear resistance four times higher than the design values tabulated in the current standards. The ductility of these CFS shear walls was also significantly improved. A preliminary equation-based nominal shear strength prediction method has been developed for the centre-sheathed shear walls; the method reflects the shear wall's different configuration and superior behaviour. Following the test data analysis, preliminary design parameters for Limit States Design (LSD) used in Canada and for Load and Resistance Factor Design (LRFD) used in the USA and Mexico were determined, including the load resistance factor, f, and the factor of safety. In addition, capacity based design parameters were determined for seismic design in Canada. These parameters included the "test-based" seismic performance factors, Rd and Ro, which were found to be 2.8 and 1.5 respectively. The superior performance of the centre-sheathed configuration showed its promising potential as a new design option for higher capacity CFS shear walls. However, before a potential implementation into mid-rise construction, further research is needed in order for a complete design procedure to be developed. " --