Utilizing an I-shaped shear link as a damper to improve the behaviour of a concentrically braced frame

2021 ◽  
Vol 186 ◽  
pp. 106915
Author(s):  
Ali Ghamari ◽  
Young-Ju Kim ◽  
Jaehoon Bae
1999 ◽  
Vol 26 (4) ◽  
pp. 379-394 ◽  
Author(s):  
M S Medhekar ◽  
DJL Kennedy

The seismic performance of single-storey steel buildings, with concentrically braced frames and a roof diaphragm that acts structurally, is evaluated. The buildings are designed in accordance with the National Building Code of Canada 1995 and CSA Standard S16.1-94 for five seismic zones in western Canada with seismicities ranging from low to high. Only frames designed with a force modification factor of 1.5 are considered. Analytical models of the building are developed, which consider the nonlinear seismic behaviour of the concentrically braced frame, the strength and stiffness contributions of the cladding, and the flexibility, strength, and distributed mass of the roof diaphragm. The seismic response of the models is assessed by means of a linear static analysis, a response spectrum analysis, a nonlinear static or "pushover" analysis, and nonlinear dynamic time history analyses. The results indicate that current design procedures provide a reasonable estimate of the drift and brace ductility demand, but do not ensure that yielding is restricted to the braces. Moreover, in moderate and high seismic zones, the roof diaphragm responds inelastically and brace connections are overloaded. Recommendations are made to improve the seismic performance of such buildings.Key words: analyses, concentrically braced frame, dynamic, earthquake, flexible diaphragm, low-rise, nonlinear, seismic design, steel.


2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Roberto Javier Merino Vela ◽  
Emanuele Brunesi ◽  
Roberto Nascimbene

Nonstructural components play an important role in the correct functioning of industrial facilities, which may suffer greatly from earthquake-induced actions, as demonstrated by past seismic events. Therefore, the correct evaluation of seismic demands acting upon them is of utmost importance when assessing or designing an industrial complex exposed to seismic hazard. Among others, nonlinear time history analyses (NLTHA) of structural systems including nonstructural elements and floor response spectra are well-known methods for computing these actions, the former being more accurate and the latter being less onerous. This work focuses on deriving floor spectra for a steel special concentrically braced frame (SCBF), which is a common type of lateral-load resisting system for industrial frames. The results are used to compute the seismic actions on a small liquid storage tank mounted on the case study frame. Additionally, the results are compared to those obtained by modeling the structure and the tank together, that is, by modeling the tank explicitly and incorporating it within the model of the support structure. To this end, a simple model, consisting of two uncoupled single degree-of-freedom systems, is used for the tank. The floor spectra resulting from both approaches are compared to establish differences in the behavior of the structure and nonstructural element/component. Finally, the seismic demand on the tank—obtained by direct and indirect analyses—is compared to that obtained by applying ASCE 7-10 and Eurocode 8 prescriptions.


2013 ◽  
Vol 29 (3) ◽  
pp. 1043-1067 ◽  
Author(s):  
Ching-Yi Tsai ◽  
Keh-Chyuan Tsai ◽  
Pao-Chun Lin ◽  
Wai-Hang Ao ◽  
Charles W. Roeder ◽  
...  

This research investigates the brace-to-gusset connection designs to allow the braces buckle in the plane (IP) of the frame. In order to study the performance of the IP buckling brace connections with different design details, five 3,026 mm–long A36 H 175 × 175 × 7.5 × 11 mm braces were tested using cyclically increasing axial displacements. All specimens failed at an average axial strain less than 0.025 due to the brace fracture at the mid-length where severe local buckling had occurred. Pseudo-dynamic tests on a three-story special concentrically braced frame (SCBF) using the proposed brace end connection details for six A36 H 150 × 150 × 7 × 10 mm braces were conducted using the PGA = 597 cm/s2 LA03 record to confirm with the component tests. The knife plates and IP buckling braces sustained a peak 0.049 rad interstory drift under the design base earthquake without fracture. The highly nonlinear responses were satisfactorily predicted by OpenSees. Recommendations on the seismic design of the IP buckling brace connections are provided.


2018 ◽  
Vol 4 (3) ◽  
pp. 655 ◽  
Author(s):  
Ali Kachooee ◽  
Mohammad Ali Kafi ◽  
Mohsen Gerami

The concentrically braced frames (CBFs) are one of the most widely used lateral load-resisting systems. Seismic performance of these structures has a weakness that is due to the brace buckling at a lower loading than the ultimate compressive loading capacity. In this paper, attempt is made to enhance the seismic response of CBFs through utilizing a local fuse. For this purpose, first the formulation of fuse area and length are presented. Then based on this formulation, several numerical models have been built and analyzed to examine the effect of implementing this fuse on seismic response of CBFs. From the analyses results, it is found that if the reduced cross-section fuse (RCF) is properly designed and also the end of brace is fixed, the CBFs with equal energy dissipation capacity, that are equipped with this fuse exhibit a better ductility than the customary CBFs.


2018 ◽  
Vol 144 (8) ◽  
pp. 04018101 ◽  
Author(s):  
Qindan Huang ◽  
Mojtaba Dyanati ◽  
David A. Roke ◽  
Akhilesh Chandra ◽  
Kallol Sett

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