Tubular Braces in Braced Steel Frames under Seismic Loading

Presented by: 

  • Professor Jeffrey A. Packer - Bahen/Tanenbaum Professor, Department of Civil Engineering, University of Toronto, CANADA
Events_201208_Tubular Frames.jpg

After the Northridge and Kobe earthquakes of the 1990s, which generated many brittle fractures in moment-resisting steel frames, the resilience of steel buildings under extreme environmental loadings has been questioned. In the quest for more sustainable building design practices, braced steel frames have become increasingly popular, post-2000, as a seismic lateral force-resisting mechanism. Hollow structural sections (HSS) are a common choice for the energy-absorbing diagonal brace member due to their high compressive resistance (since there is no weak axis for buckling). Designers need to select between round and square (or rectangular) HSS and also consider the type of steel material being used – either cold-formed or hot-formed (hot-finished) sections. This issue, and another regarding how best to design the brace end connections, are the two principal outstanding problems still clouding design. These two matters are the principal topic of this presentation. 

A four-part research investigation is described, which ultimately provides solutions for: 

  • Fabricated connections at the brace ends, which avoid connection reinforcement
  • Cast steel connectors at the brace ends, where the casting remains elastic
  • Type of tube material, for energy-dissipating round HSS brace members
  • Cast steel connectors at the brace ends, where the casting itself yields and provides the energy dissipation. 

The novel cast steel devices cited above have resulted in patented innovations leading to a University of Toronto spin-off company that designs, manufactures and markets the products. This university-assisted commercialization effort is also described. 

Professor Jeffrey Packer graduated from the University of Adelaide in 1972 with first class honours in his Bachelor of Engineering degree. He subsequently completed an M.Sc. at the University of Manchester, U.K. and a Ph.D. at the University of Nottingham, U.K. He was awarded a Doctor of Science (D.Sc.) at the University of Nottingham in 2006. Professor Packer is a world-renowned expert in the field of tubular steel construction. 

He is the co-author of 15 books, spanning 5 languages, and over 200 journal articles and conference papers. In the last 10 years Professor Packer has been the Principal Investigator for grants and contracts at the University of Toronto totalling over $8.7 million dollars. In 2010-2011 Professor Packer was instr`umental in the establishment of the University of Toronto’s new multi-disciplinary “Centre for the Resilience of Critical Infrastructure”. The Centre is highly dependent upon a unique structural resilience expertise within theDepartment of Civil Engineering at the University of Toronto. 

This event will be held in Lecture Theatre C1 at The University of Melbourne, Engineering Block C, Level 4. View map.

This event will start at  6:00pm, with refreshments from 5:30pm

All of the IStructE Technical Meetings are free to attend unless stated otherwise.