Upgrade of Seismically Deficient Steel Frame Structures Built in Canada Between the 1960s and 1980s Using Passive Supplemental Damping

• Main Author: Kyriakopoulos, Nikolas
• Other Authors: Christopoulos, Constantin
• Language: en_ca
• Published: 2012
• Subjects: steel moment-resisting frames; Type 2 Construction; nonlinear time-history analysis; supplemental damping; performance-based design; 0543
• Online Access: http://hdl.handle.net/1807/33281

A typical 1960s Type 2 Construction steel MRF hospital structure in Quebec, representative of a prevalent construction philosophy of the time, was investigated and modelled in OpenSees using an advanced strength degradation model. The structure was then subjected to a nonlinear time-history analysis (NLTHA) for Montreal (MTL) and Vancouver (VAN) ground motions and was found to be deficient under the design hazard levels. Retrofits were proposed for the two orthogonal frames at both sites using a performance-based approach. An experimental program determined that the connections had less ductility than expected and began deteriorating around 2.0% interstorey drift. The OpenSees model was updated according to the experimental connection behaviour and the predicted NLTHA performance of the structure worsened. The proposed retrofit designs for both orthogonal frames in both MTL and VAN were updated with the new connection behaviour and final retrofit designs were proposed.