Applicability of the direct displacement-based design procedure to concentrically braced frames with setbacks

2021 ◽  
Vol 6 (3) ◽  
pp. 167-176
Author(s):  
Suhaib Salawdeh
2016 ◽  
Vol 847 ◽  
pp. 281-289
Author(s):  
Erkan Senol ◽  
Ismail Kose ◽  
Bilge Doran ◽  
Pelin Elif Mezrea ◽  
Bulent Akbas

Adding braces to moment frames is considered to be quite an efficient technique for increasing the global stiffness and strength of the structure. It has not only been used in steel moment frames, but also in reinforced concrete (RC) moment frames in recent years. It certainly can increase the energy absorption capacity of structures and also decrease the demand imposed by seismic ground motions. Steel braces are anchored firmly to boundary beams and columns. They are modeled as truss elements and increase earthquake resistance of the building. Buckling restrained braced frames (BRBFs) in which members yield under both tension and compression without significant buckling have been used in recent years in order to ensure the desired seismic performance of special concentrically braced frames. BRBFs are similar to the special concentrically braced frames in that seismic accelerations are resisted by a building-frame members and diagonal braces whereas the design procedure is different. BRBs should be designed to permit ductile yielding both in compression and tension. In this paper, flat-slab RC building with two different configurations of buckling restraint braces (BRBs) is studied. The buildings have 4-storey with 5 bays in both X-and Y-directions and have been designed according to Turkish Specification of Reinforced Concrete Design (TS 500). In order to explore overall behavior up to failure and lateral load resisting capacities for these buildings, nonlinear static analyses have then been performed using SAP 2000-V14.1. Pushover analysis under constant gravity loads and monotonically increasing lateral forces during an earthquake until a target displacement is reached is generally carried out as an effective tool for performance based design. The major outcome of a pushover analysis is the capacity curve which shows the base shear vs. the roof displacement relationship and represents the overall performance of the building. The results of the analyses are presented in terms of capacity curve and energy dissipation.


Buildings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 196 ◽  
Author(s):  
Silvia Costanzo ◽  
Roberto Tartaglia ◽  
Gianmaria Di Lorenzo ◽  
Attilio De Martino

The design procedure codified within current Eurocode 8 for dissipative moment resisting and concentrically braced frames have led to the design of massive systems characterized in the most of cases by poor energy dissipation capacity. The research activity presented in the current paper addresses the identification of the main criticisms and fallacies in the current EN 1998-1 for those seismic-resistant typologies. In this regard, the design provisions and codified rules for both moment resisting frames (MRFs) and chevron concentrically braced frames (CCBFs) are critically discussed and numerically investigated. Static and incremental dynamic analyses were performed on a set of 3 and 6-story frames designed compliant to EN 1998-1. The results from the numerical analyses are reported and discussed.


Author(s):  
Eshagh Derakhshan Houreh ◽  
Ali Imanpour

Steel Multi-Tiered Concentrically Braced Frames (MT-CBFs) represent a bracing configuration where two or more concentric bracing panels are stacked between the ground and roof levels in tall single-storey buildings. A large proportion of MT-CBFs in Canada are located in low-to-moderate seismic regions (Seismic Category 0 – 3) where Limited Ductility CBFs are often preferred in design. Nevertheless, brace tensile yielding may not occur in all tiers of such frames. Additionally, the analysis and design procedure adopted by the 2019 Canadian steel design standard (CSA S16-19) can become tedious in tall frames with multiple panels. In this paper, the seismic behaviour of Limited Ductility MT-CBFs in moderate seismic regions of Canada is examined to propose a simplified design method. A set of 16 prototype MT-CBFs is designed in accordance with CSA S16-19, excluding the design requirements prescribed for MT-CBF columns. Nonlinear dynamic analyses are then performed to examine their seismic response. Finally, an efficient design method is proposed in the framework of CSA S16-19.


2018 ◽  
Vol 763 ◽  
pp. 1147-1154 ◽  
Author(s):  
Silvia Costanzo ◽  
Mario D'Aniello ◽  
Raffaele Landolfo ◽  
Attilio de Martino

Chevron concentrically braced frames (C-CBFs) are expected to provide limited ductility in the framework of Eurocode 8: differently from North American codes, lower values of behavior factors are recommended by EN 1998 for C-CBFs than for other concentric bracing configurations (namely diagonal and cross bracings). The research presented in this paper is aimed at revising the design rules and requirements provided for by EN 1998-1 for C-CBFs in order to improve the ductility and the dissipative capacity of this structural system. The proposed design criteria are validated by means of nonlinear dynamic analyses performed on a study case. The results confirm the effectiveness of developed design procedure.


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