Seismic Response of Eccentrically Braced Frames

The paper is devoted to the investigation of the seismic response of eccentrically braced frames characterised by links having different length. In addition, the analysed structures have been designed according to a methodology, already proposed by the authors, aiming to guarantee a collapse mechanism of global type. Therefore, the results of the nonlinear analyses herein presented provide the validation of the proposed design procedure, by testifying that all the designed structures exhibit a global failure mode where all the links are yielded while all the columns remain in elastic range with the exception of the base section of first storey columns, leading to high energy dissipation capacity and global ductility. Furthermore, two different distributions of the link lengths are examined. The first one is characterised by short links with uniform lengths along the height of the structure. The second one is characterised by the use of link elements having different length at the different storeys which are selected to assure the same value of the non-dimensional link length. The seismic response of EB-Frames with such distributions of the link length is investigated by means of both push-over analyses and dynamic non-linear analyses. The comparison of the performances is mainly carried out in terms of plastic hinges distribution, local ductility demand and frame lateral stiffness.

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Design and seismic response of shear critical eccentrically braced frames

Canadian Journal of Civil Engineering ◽

10.1139/l97-016 ◽

1997 ◽

Vol 24 (5) ◽

pp. 761-771 ◽

Cited By ~ 10

Author(s):

S Koboevic ◽

R Redwood

Keyword(s):

Seismic Response ◽

Braced Frames ◽

Eccentrically Braced Frames

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Design and seismic behaviour of taller eccentrically braced frames

Canadian Journal of Civil Engineering ◽

10.1139/l09-131 ◽

2010 ◽

Vol 37 (2) ◽

pp. 195-208 ◽

Cited By ~ 7

Author(s):

Sanda Koboevic ◽

Simona Olivia David

Keyword(s):

Seismic Response ◽

Seismic Performance ◽

Control Design ◽

Design Criteria ◽

Braced Frames ◽

Local Response ◽

Shear Forces ◽

Seismic Behaviour ◽

Eccentrically Braced Frames ◽

Global And Local

This paper describes a study of the seismic behaviour of taller eccentrically braced frames (EBFs). Chevron-type EBFs with shear-critical links are designed for 14-, 20-, and 25-storey buildings in Montreal and Vancouver. For each location the importance of different design criteria is discussed and an appropriate design sequence is proposed. It was found that ductility requirements did not control design. For Vancouver, buildings member selection was mostly influenced by the inelastic inter-storey drift requirements whereas for Montreal ensuring the global frame stability was critical. The seismic response of these frames to the sets of earthquake records calibrated to match design spectra is described. The seismic performance for Vancouver frames was found to be adequate, except that in the upper storeys the inelastic link deformations and shear forces exceeded values anticipated in design. For the Montreal structures, all global and local response indicators remained well below the design limits.

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Evaluation of Seismic Response Factors for Eccentrically Braced Frames Using FEMA P695 Methodology

Earthquake Spectra ◽

10.1193/071014eqs097m ◽

2016 ◽

Vol 32 (1) ◽

pp. 303-321 ◽

Cited By ~ 10

Author(s):

Ahmet Kuşyılmaz ◽

Cem Topkaya

Keyword(s):

Seismic Response ◽

Amplification Factor ◽

Numerical Study ◽

Braced Frames ◽

Response Factors ◽

Eccentrically Braced Frames ◽

Collapse Probability ◽

Collapse Models ◽

Deflection Amplification Factor

This paper reports details of a numerical study undertaken to evaluate seismic response factors for steel eccentrically braced frames (EBFs) using the FEMA P695 methodology. Six archetypes were designed by making use of the current U.S. specifications, and their behavior was assessed by making use of nonsimulated collapse models. Results indicate that the current values of response factors result in designs with higher collapse probabilities than expected. Two modifications were developed to bring the collapse probability of these archetypes to acceptable levels. The first modification is on the deflection amplification factor while the second one is on the response modification coefficient. Six archetypes were redesigned using the proposed modifications and reevaluated using the FEMA P695 methodology. The results indicate that the proposed modifications are adequate to satisfy the target collapse probability. Maximum and cumulative link rotation angles were observed to be less than the predefined limits.

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