PRESENTATION: Designing for Reoccupancy with Controlled Rocking Braced Frames

Presentation

When – 5:30pm – Wednesday 11 March 2020//

Where – University of Auckland, Symonds Street, Auckland Lecture Theatre Room (401.401). This is in Engineering Building next to the lift. (Refer City Campus Map below).

Agenda –
17:50 pre-presentation refreshments
18:00 presentation

Please register for this presentation below:

Abstract

Because of their potential to avoid structural damage during design-level earthquakes, controlled rocking braced frames (CRBFs) are attracting interest from researchers and practicing engineers alike. In a CRBF, selected columns are permitted to uplift from the foundation, limiting the peak seismic forces while also avoiding structural damage and residual deformations. Post-tensioning and/or energy dissipation technologies are used to control the response.

This seminar will use examples from both research and practice to examine four key issues for the design of CRBFs:

1. A designer has a wide range of options for selecting post-tensioning and energy dissipation. These options will be demonstrated using practical examples, and studies of the displacement response of self-centering systems will be linked to collapse risk analysis.
2. The capacity design of the frame must account for the forces that develop due to the higher modes. Shake table test results will be used to illustrate how these forces develop and can be mitigated, methods for predicting these forces will be assessed based on nonlinear time history analysis, and the influence of these forces on collapse risk will be identified.
3. The connections between the CRBF and the floor diaphragms are critical to the overall behaviour of the structure. Several connection methods will be discussed, using illustrations from both practice and large-scale laboratory testing.
4. The seismic performance of non-structural elements is critical to reoccupancy, but the demands on these elements may be different from the demands in buildings with other seismic force resisting systems, as will be shown based on recent numerical modelling.

Finally, a few other ongoing research projects related to design for reoccupancy with steel, wood, and masonry will also be introduced.

Biography

Dr. Lydell Wiebe works to develop simple, inexpensive solutions for problems in earthquake engineering and structural dynamics. His research at McMaster University focuses on predicting and mitigating damage due to earthquakes, particularly for steel structures, by using advanced nonlinear analysis tools and large-scale physical testing. Dr. Wiebe is Vice-Chair of Working Group 9 (Seismic Design) for CAN/CSA S16 (Design of Steel Structures) and Vice-President of the Canadian Association for Earthquake Engineering, and he led the writing of the New Zealand Design Guide for Controlled Rocking Steel Braced Frames. He holds a PhD in Civil Engineering from the University of Toronto and an MSc in Earthquake Engineering from the ROSE School in Pavia, Italy, and is registered as a professional engineer in the Province of Ontario.

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