A design procedure for suspended zipper-braced frames in the framework of Eurocode 8

2017 ◽  
Author(s):  
Pier Paolo Rossi ◽  
Giuseppe Quaceci
Keyword(s):  
Design Procedure ◽  
Eurocode 8 ◽  
Braced Frames

scholarly journals On the European Norms of Design of Buckling Restrained Braced Frames

2017 ◽  
Vol 11 (1) ◽  
pp. 513-530 ◽  
Author(s):  
Ádám Zsarnóczay ◽  
Tamás Balogh ◽  
László Gergely Vigh
Keyword(s):  
Seismic Design ◽  
Structural Reliability ◽  
Design Procedure ◽  
Material Model ◽  
Eurocode 8 ◽  
Braced Frames ◽  
Reliability Indices ◽  
Buckling Restrained Braces ◽  
Buckling Restrained Braced Frames ◽  
Ground Motion Records

The application of buckling restrained braced frames is hindered in Europe by the absence of a standardized design procedure in Eurocode 8, the European seismic design standard. The presented research aims to develop a robust design procedure for buckling restrained braced frames. A design procedure is proposed by the authors. Its performance has been evaluated for buckling restrained braced frames with two-bay X-brace type brace configurations using a state-of-the-art methodology based on the recommendations in the FEMA P695 document. A special numerical material model was developed within the scope of this research to represent the behavior of buckling restrained braces more appropriately in a numerical environment. A total of 24 archetype designs were prepared and their nonlinear dynamic response was calculated using real ground motion records in incremental dynamic analyses. Evaluation of archetype collapse probabilities confirms that the proposed design procedure can utilize the advantageous behavior of buckling restrained braces. Resulting reliability indices suggest a need for additional regulations in the Eurocodes that introduce reasonable structural reliability index limits for seismic design.

scholarly journals Evolution of EC8 Seismic Design Rules for X Concentric Bracings

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1807
Author(s):  
Alessia Campiche ◽  
Silvia Costanzo
Keyword(s):  
Seismic Design ◽  
Structural Engineering ◽  
Design Procedure ◽  
Eurocode 8 ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Design Rules ◽  
Factor Ii ◽  
And Behavior ◽  
Seismic Area

Eurocodes are currently under revision within a six-year program by CEN/TC 250. In this framework, concentric bracings, particularly in cross configuration, have been largely debated; indeed, several criticisms affect the seismic design procedure currently codified within Eurocode 8, entailing significant design efforts and leading to massive and non-economical structural systems, even characterized by poor seismic behavior. The efforts of SC8 have been aimed at improving the codified seismic design criteria for concentrically braced frames, by providing requirements and detailing rules conceived to simplify the design process and to improve the seismic performance. The current paper provides recent advances in the field of computational and structural engineering focusing on symmetric X concentrically bracings in seismic area, outlining the evolution of Eurocode 8 (EC8) seismic design rules, by examining the following aspects: (i) ductility class and behavior factor, (ii) analysis and modelling aspects, (iii) design of dissipative members; (iv) design of non-dissipative zones; (v) brace-to-frame connections.

scholarly journals Seismic Behaviour of EC8-Compliant Moment Resisting and Concentrically Braced Frames

Buildings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 196 ◽  
Author(s):  
Silvia Costanzo ◽  
Roberto Tartaglia ◽  
Gianmaria Di Lorenzo ◽  
Attilio De Martino
Keyword(s):  
Design Procedure ◽  
Eurocode 8 ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Research Activity ◽  
Seismic Behaviour ◽  
Concentrically Braced ◽  
Dynamic Analyses ◽  
Moment Resisting ◽  
Energy Dissipation Capacity

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.

Remarks on Seismic Design Rules of EC8 for Inverted-V CBFs

2018 ◽  
Vol 763 ◽  
pp. 1147-1154 ◽  
Author(s):  
Silvia Costanzo ◽  
Mario D'Aniello ◽  
Raffaele Landolfo ◽  
Attilio de Martino
Keyword(s):  
Design Procedure ◽  
Eurocode 8 ◽  
Structural System ◽  
Braced Frames ◽  
Concentrically Braced Frames ◽  
Design Rules ◽  
Concentrically Braced ◽  
Dynamic Analyses ◽  
Study Case ◽  
Nonlinear Dynamic Analyses

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.

scholarly journals An Alternative Approach for the Design of Chevron-Braced Frames

2021 ◽  
Vol 11 (22) ◽  
pp. 11014
Author(s):  
Francesca Barbagallo ◽  
Melina Bosco ◽  
Marco Caragliano ◽  
Edoardo M. Marino ◽  
Pier Paolo Rossi
Keyword(s):  
Seismic Performance ◽  
Design Procedure ◽  
Eurocode 8 ◽  
Braced Frames ◽  
Limit States ◽  
Alternative Approach ◽  
Significant Damage ◽  
Internal Forces ◽  
Ductility Capacity ◽  
Elastic Design

The design of steel chevron-braced frames as per Eurocode 8 is based on the idea that only the braces should buckle and yield during ground motions, while other members should remain elastic. The elastic design of the braced frames is also allowed. However, in both cases, the seismic performance of the frame may be compromised because of premature yielding/buckling of columns. This paper proposes an alternative design procedure that promotes yielding of beams in addition to yielding of braces. This mitigates the vertical unbalanced force transmitted by compressive and tensile braces to the beam and in turn reduces the internal forces of the columns. The result is the overall improvement of the seismic performance owing to the reduction of the number of cases in which failure of the columns occurs before full exploitation of the ductility capacity of the dissipative members. The proposed design procedure is validated by incremental dynamic analyses performed on a set of chevron-braced frames. In particular, the peak ground accelerations of the frames designed by the proposed procedure at the attainment of Significant Damage and Collapse Prevention limit states are determined and compared to those of frames designed according to Eurocode 8. Furthermore, frames designed according to the Eurocodes and to the proposed method are compared in terms of structural cost.

Drift-based seismic design procedure for Buckling Restrained Braced Frames

Structures ◽  
2021 ◽  
Vol 30 ◽  
pp. 62-74
Author(s):  
Seyed Amin Mousavi ◽  
Seyed Mehdi Zahrai ◽  
Ali Akhlagh Pasand
Keyword(s):  
Seismic Design ◽  
Design Procedure ◽  
Braced Frames ◽  
Buckling Restrained Braced Frames

Behavior Factor of Dual Systems with BRBs and Semi-Rigid Connections

2018 ◽  
Vol 763 ◽  
pp. 949-956 ◽  
Author(s):  
Francesca Barbagallo ◽  
Melina Bosco ◽  
Edoardo Michele Marino ◽  
Pier Paolo Rossi
Keyword(s):  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Design Procedure ◽  
Eurocode 8 ◽  
Deformation Capacity ◽  
Structural System ◽  
Dual Systems ◽  
Behavior Factor ◽  
Soft Story ◽  
Collapse Mechanisms

The use of BRBs into a typical European building with braced structure, whereby all the beam-to-column connections are perfectly pinned, may be low effective. In fact, these structures are low-redundant and prone to develop soft story collapse mechanisms. The concentration of drift demand in few stories precludes the full exploitation of the deformation capacity of all the BRBs inserted into the frame, and it partially reduces the benefit they can provide. A more effective structural system may be obtained by coupling frames with BRBs with frames with semi-rigid connections. This paper proposes a design procedure for this dual system and presents the calibration of the behavior factor. To this end, a set of frames is designed considering several values of behavior factor and the response of the obtained frames is determined by nonlinear dynamic analysis. Hence, the behavior factor that allows the frames to meet the performance objective requirement of EuroCode 8 is determined.

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