TA project: BRACED

Click here to read the final report of the BRACED project.

Click here to watch a video from the BRACED experiments.

A concise presentation of the project's aim and main outcomes is available at the SERIES TA joint brochure.

TITLE OF PROPOSAL: Assessment of the Seismic Response of Concentrically-Braced Steel Frames

CEA, Saclay, France

September 2010

February, 10th 2010 (kick off meeting)

May 2013

NO. OF USERS (researchers):

Brian Broderick - Trinity College Dublin (Ireland)

Alan Hunt - Trinity College Dublin (Ireland)
Jamie Goggins - National University of Ireland, Galway
Suhaib Salawdeh - National University of Ireland, Galway
Gerard O'Reilly - National University of Ireland, Galway
Darko Beg - University of Ljubljana (Slovenia)
Primoz Moze - University of Ljubljana (Slovenia)
Franc Sinur - University of Ljubljana (Slovenia)
Ahmed Elghazouli - Imperial College London (UK)


The proposed research will investigate the ultimate behaviour of concentrically braced frames (CBFs). The seismic performance of these structuresisaffected by the reduced ductility capacity of hollow section bracing members under low cycle fatigue conditions. In addition, there is a need for improved design and detailing guidance for the gusset-plate connections commonly used in CBFs, especially for the case of out-of-plane buckling. The proposed research will validate recently-developed models for the ductility capacity of hollow section bracing members and recent proposals for the improved detailing of gusset plate connections. It will identify active yield mechanisms and failure modes in member/connection combinations and provide essential data on the earthquake response of European CBFs.
An integrated experimental and numerical research programme will be carried out by the project team, the central element of which will be a series of shake table experiments on full-scale model single-storey CBFs designed to Eurocode 8. The brace member and connection details will be varied between experiments to investigate the range of global and local member slenderness found in European design practice. In each experiment, three separate tests will be performed with table excitations scaled to produce elastic response, brace buckling/yielding and brace fracture. These experiments will be supported by correlative pre-test predictions and post-test simulations using pushover and time-history analysis.
The experimental programme will produce a unique set of data on the ultimate earthquake response of CBFs with realistic brace members and connections. The principal outcomes will include measurements of the displacement ductility capacity of the brace specimens; an evaluation of the influence of gusset plate detailing on connection ductility; observations on the contributions of brace and connection yielding to overall inelastic deformation of CBFs; measurements of equivalent viscous damping in CBFs; assessment and improvement of Eurocode 8 design guidance for CBFs; and validation of numerical models.

Model CBF on Azalee shaking table (without added mass)

What's next

Series logo small   SERIES Concluding Workshop
  Joint with US-NEES "Earthquake Engineering Research Infrastructures

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