Evidence collected for peer review of buckling-restrained braced frames in New Zealand

Buckling-restrained braces (BRBs) form a bracing system that provides lateral strength and stiffness to a building. These systems have been shown to provide larger energy dissipation in severe earthquake events compared to concentrically and eccentrically braced frames (CBFs and EBFs). However, unlike CBFs and EBFs there is no guidance document or specific instructions in regulatory standards for the design of buckling-restrained braced frames (BRBFs) in New Zealand. This makes it difficult for structural engineers to be aware of all the strength and stability considerations required for the safe design of BRBFs. Currently, structural designs that include BRBFs require a peer-review to gain building compliance. The American standard ANSI/AISC 341-16 is the adopted document used in New Zealand for guidance in how to collect evidence showing a BRBF system will perform as intended. However, as ANSI/AISC 341-16 is not a governing document in New Zealand, instructions within the document are not enforced and can be made to fit within the constraints of a building project. By way of example, this paper presents the experimental test process and results acquired from pre-qualification testing of three different commercially available BRB architypes. Of the three BRB designs investigated, one failed prematurely due to global buckling. A manufacturing error was the likely cause of this premature failure. This failure highlights the need for strict quality control during fabrication. All remaining BRBs performed well, meeting the acceptance criteria set out in ANSI/AISC 341-16. Positive pre-qualification results meant the BRBs were installed in medium to high-rise buildings throughout New Zealand. The importance of sub-assemblage testing to assess the performance of a BRB and its frame components is also discussed. Finally, the capability of high fidelity modelling to supplemental physical testing is also presented.

Download Full-text

Buckling-Restrained Braces (BRB) Seismic Design - A Consulting Engineer’s Consideration

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.763.932 ◽

2018 ◽

Vol 763 ◽

pp. 932-940

Author(s):

Weng Yuen Kam ◽

Richard Built ◽

Brandt Saxey ◽

Jerod Johnson

Keyword(s):

New Zealand ◽

Peer Review ◽

Seismic Design ◽

System Structure ◽

Design Standards ◽

International Convention ◽

Direct Displacement Based Design ◽

Buckling Restrained Braces ◽

Moment Resisting ◽

Bracing System

There is no standard for the design of Buckling-Restrained Braces (BRBs) frames in New Zealand. Consequently, a consulting engineer would need to consider a range of overseas design standards and latest research findings and incorporate into a New Zealand code-compliance framework. This “Alternative Solution” pathway to satisfy the New Zealand Building Code means peer review and agreement with peer review is required. This paper describes the design journey and technical challenges the authors had in the seismic design of the BRB for the New Zealand International Convention Centre (NZICC). BRB frames are used as the primary ductile lateral load bracing system, acting in parallel with the moment-resisting frames formed by the primary cruciform columns and storey-deep trusses. Due to the vertical irregularity and a dual-system structure, a direct displacement-based design (DDBD) approach was used in parallel with a more convention code-compliant force-based design, to derive the BRB design actions. The design of the BRB connections, in particular the gusset design is particularly challenging due to the diverging views and numerous methodologies available. We have considered several analytical methods for the BRB connection design and commissioned two full-scale testing of the critical BRB and the gusset connection. Lessons learnt

Download Full-text

Comparison of seismic design provisions for buckling restrained braced frames in Canada, United States, Chile, and New Zealand

Structures ◽

10.1016/j.istruc.2016.06.004 ◽

2016 ◽

Vol 8 ◽

pp. 183-196 ◽

Cited By ~ 6

Author(s):

R. Tremblay ◽

M. Dehghani ◽

L. Fahnestock ◽

R. Herrera ◽

M. Canales ◽

...

Keyword(s):

United States ◽

New Zealand ◽

Seismic Design ◽

Braced Frames ◽

Buckling Restrained Braced Frames

Download Full-text

Drift-based seismic design procedure for Buckling Restrained Braced Frames

Structures ◽

10.1016/j.istruc.2020.12.077 ◽

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

Download Full-text

Bidirectional loading performance of gusset plates in buckling restrained braced frames

Engineering Structures ◽

10.1016/j.engstruct.2021.112521 ◽

2021 ◽

Vol 242 ◽

pp. 112521

Author(s):

Saul Y. Vazquez-Colunga ◽

Chin-Long Lee ◽

Gregory A. MacRae

Keyword(s):

Braced Frames ◽

Gusset Plates ◽

Buckling Restrained Braced Frames

Download Full-text

Effects of Out-of-Plane Displacements on Load Capacity of Gusset Plates in Buckling Restrained Braced Frames

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.763.892 ◽

2018 ◽

Vol 763 ◽

pp. 892-899 ◽

Cited By ~ 2

Author(s):

Saul Y. Vazquez-Colunga ◽

Chin Long Lee ◽

Gregory A. MacRae

Keyword(s):

Finite Element ◽

Finite Element Methods ◽

Load Capacity ◽

Numerical Results ◽

Numerical Analyses ◽

Braced Frames ◽

Gusset Plates ◽

Out Of Plane ◽

Buckling Restrained Braced Frames ◽

Monotonic Load

This study sets out to investigate the effect of out-of-plane (OOP) displacements on the monotonic load capacity of gusset plates (GPs) via numerical analyses using finite element methods. Two models were used: a) models with in-plane (INP) actions only; and b) models with both INP and OOP actions. The numerical results show that the load capacity of GPs is reduced with the presence of OOP displacements. For an OOP drift of 2.5%, the reduced capacity ranges from 95% to 80% with an average of 88% of the load capacity when only INP actions were applied.

Download Full-text

Investigations on Efficiently Interfaced Steel Concrete Composite Deck Slabs

Journal of Structures ◽

10.1155/2013/628759 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 6

Author(s):

K. N. Lakshmikandhan ◽

P. Sivakumar ◽

R. Ravichandran ◽

S. Arul Jayachandran

Keyword(s):

Longitudinal Shear ◽

Advanced Technology ◽

Shear Connector ◽

Premature Failure ◽

Shear Connectors ◽

Reinforced Concrete Slabs ◽

Composite Slabs ◽

Strength And Stiffness ◽

The Cost ◽

Deck Slab

The strength of the composite deck slab depends mainly on the longitudinal shear transfer mechanism at the interface between steel and concrete. The bond strength developed by the cement paste is weak and causes premature failure of composite deck slab. This deficiency is effectively overcame by a shear transferring mechanism in the form of mechanical interlock through indentations, embossments, or fastening studs. Development of embossment patterns requires an advanced technology which makes the deck profile expensive. Fastening studs by welding weakens the joint strength and also escalates the cost. The present investigation is attempted to arrive at a better, simple interface mechanism. Three types of mechanical connector schemes are identified and investigated experimentally. All of the three shear connector schemes exhibited full shear interaction with negligible slip. The strength and stiffness of the composite slabs with shear connectors are superior about one and half time compared to these of the conventional reinforced concrete slabs and about twice compared to these of composite slabs without mechanical shear connectors. The scheme2 and scheme3 shear connector mechanisms integrate deck webs and improve strength and stiffness of the deck, which can effectively reduce the cost of formworks and supports efficiently.

Download Full-text

Comparative Evaluation of Concentric Bracing Systems for Lateral Loads on Medium Rise Steel Building Structures

International Journal of Scientific Research in Science and Technology ◽

10.32628/ijsrst207428 ◽

2020 ◽

pp. 124-130

Author(s):

Sisaynew Tesfaw Admassu

Keyword(s):

Lateral Displacement ◽

Level Structure ◽

Lateral Load ◽

Frame Structure ◽

Lateral Stiffness ◽

Building Structures ◽

Steel Buildings ◽

Lateral Strength ◽

Strength And Stiffness ◽

Bracing System

To resistance, the lateral load from wind or an earthquake is that the reason for the evolution of varied structural systems. Because, when a medium or any multi-level structure is exposed to horizontal or torsional deflections under the action of seismic burdens. Lateral stiffness is a major consideration in the design of the buildings. In addition to this, many existing steel buildings and reinforced concrete buildings for which the weak lateral stiffness is the main problem; should be retrofitted to conquer the insufficiencies to resist the lateral loading. Lateral load resisting systems are structural elements providing basic lateral strength and stiffness, without which the structure would be laterally unstable. The unstable nature of the structure is solved by the fitting arrangement of bracings systems. A bracing system is that forms an integral part of the frame. Thus, such a structure has to be analyzed before arriving at the best type or effective arrangement of bracing. Bracing is a highly effective strategy of resisting lateral forces in a frame structure. In this document, a ten-story building with incorporated bracing systems is analysed using ETABS 2016 analysis software as per Eurocode and Ethiopian Building Code Standards (EBCS). Then, the lateral displacement is evaluated under each of the bracing types.

Download Full-text