Advancements In The Seismic Design Of Cold Formed Steel Structures Through The Investigation Of Diaphragm Behaviour And The Influence Of Non Structural Components PDF Download

"Seismic design provisions for wood sheathed / cold-formed steel (CFS) framed shear walls and CFS strap braced walls are available in the AISI S213-07 Standard. However, the National Building Code of Canada (NBCC), as well as the CSA S136 and the AISI S213 Standards, at present, do not address the seismic design of steel sheathed / CFS framed shear walls for use in Canada. The existing design guidelines for CFS framed shear walls are based on data obtained from static tests carried out under both monotonic and reversed cyclic loading protocols. The objective of this research was to develop seismic design provisions for the CFS framed shear walls forming part of the seismic force resisting system of a building, with the intent to recommend that they be included in the NBCC and AISI S213. The approach involved shake table testing of single- and double-storey CFS framed steel and wood sheathed shear walls, numerical modeling of the tested shear walls, and, lastly, non-linear time history dynamic analyses of building archetypes following the Federal Emergency Management Agency (FEMA) P695 methodology. Overall, seven wood sheathed and ten steel sheathed CFS framed shear walls were tested on the Ecole Polytechnique de Montréal structural laboratory shake table. The wall specimens were full-scale single- and double-storey walls and, most, were constructed with the blocking in the CFS frame. A wood sheathed shear wall was tested with a gypsum panel on one side of the specimen in order to investigate the effects of non-structural components. The dynamic test program included impact tests, harmonic forced vibration tests, and ground motion tests representative of the seismic hazard in Quebec and Vancouver, Canada. The seismic performance of the dynamically tested shear walls, i.e. force vs. displacement hysteretic behaviour and failure modes, was primarily similar to the static tests. Inclusion of the blocking increased the shear strength of the tested shear walls by almost 50%. OpenSees software was used for the numerical modelling of the dynamically tested walls. The inelastic behaviour of the shear walls was replicated by using the Pinching04 material; additional zerolength spring elements were included in the model to represent frame stiffness, anchor rod stiffness and the CFS framing. The wall models were calibrated based on the results of the dynamic tests, as well as data obtained from the calibration of previously performed static tests. Moreover, to provide experimental data to complete the model calibration procedure a series of static tests was conducted on blocked CFS bare frames and stud-to-track connections. The archetype buildings (twelve in total) were two, four and five storey office and residential buildings located in Halifax, Montreal and Vancouver, Canada. The buildings designed with Rd = 2.0 and Ro = 1.3 satisfied the FEMA P695 collapse capacity requirements. Inclusion of gypsum panel in two of the archetype buildings increased the collapse margin ratio by 20% on average." --