Mechanics, Materials Science & Engineering, July 2017 – ISSN 2412-5954
Seismic Behaviour of Eccentrically Braced Frame with Vertical Link 1
Vahid Osat1, Ehsan Darvishan2,a, Morteza Ashoori3 1 – M. Sc., Department of Civil Engineering, College of engineering, Roudehen Branch, Islamic Azad university, Roudehen, Iran 2 – Assistant Professor, Department of Civil Engineering, College of engineering, Roudehen Branch, Islamic Azad university, Roudehen, Iran 3 – M. Sc., Department of Civil Engineering, Sharif University of Technology, Tehran, Iran a – Darvishan@riau.ac.ir DOI 10.2412/mmse.25.78.451 provided by Seo4U.link
Keywords: steel, eccentrically braced frame, vertical link, time history, seismic performance, nonlinear analysis.
ABSTRACT. The design of an eccentrically braced frame is based on providing a weak section in frame which will remain essentially elastic outside a well define link. Eccentrically braced frames combine stiffness of centrically braced frame with ductility and capability to dissipate seismic energy of moment resistant frame. In this paper the seismic behavior of eccentrically braced frame with vertical link is presented. Three regular frame with vertical link which its length is correlated to the capability to dissipate seismic energy are considered. The analytical models used to simulate the test through inelastic time history analyses that is performed in OpenSees software and simulation results were obtained. The results indicated that by reducing the vertical link length in EBFs, the maximum lateral displacements of roofs have been reduced for all frames due to 5 real earthquake records. Reducing the vertical link length decreases the maximum base shear of the structure. Therefore, it can be said that vertical link length improved the seismic performance of the EBFs.
Introduction. Eccentrically braced frames (EBF) which are used in seismic design and seismic rehabilitation of structure in seismic areas constitute a suitable compromise between seismic resistant moment resistant frames and concentrically braced frames. In EBF frames, a horizontal or vertical eccentricity (e) forms at the end of brace members that is called link or fuse. There are two type eccentrically braced frame, eccentrically braced frame with vertical and horizontal link that are shown in Fig. 1. One of the advantages of vertical links over their horizontal counterparts is the exclusion of plastic deformation from the main structure result on no damage in the roof of the structures under severe earthquake; easy and simple rehabilitation; and the replacement of link after earthquake. using the vertical links for seismic rehabilitation of the existing buildings is possible with minor changes in the main structure; however, in large or tall building and also in strengthening of the existing structures, due to limitation of dimensions of the existing components of the structures, the application of the single vertical link has lots of obstacles. The transferred shear from the vertical links, especially in concrete structures, can limit the application of big vertical links. In such case, using double vertical links is recommended[1].
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© 2017 The Authors. Published by Magnolithe GmbH. This is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/
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