- Review of buckling restrained brace design and behaviour
- A.S. Jones ; C-L Lee ; G.A. MacRae ; G.C. Clifton
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Structure types ; Steel structures
- Keywords: Buckling restrained braces ; brace design
- Description
- Buckling restrained braces (BRBs) have become a popular alternative to traditional bracing in seismic loading due to their ability to develop full and balanced hysteresis loops resulting in similar tension and compression capacities. However, research internationally for the design and behaviour of BRB compositional elements is still in the infancy stage, with intellectual property rights by commercial providers within America and Asia limiting the available research.
This paper considers the history and development of BRBs (steel-concrete and steel-steel), current design practice, areas for further development and forthcoming research to be carried out that the University of Canterbury. The outcomes of this research which consider the sensitivity in BRB member design aims to equip engineers with an understanding of BRBs but also the ability to design BRBs without the need for testing verification.
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- Seismic design of composite metal deck and concrete-filled diaphragms - A discussion paper
- K.A. Cowie ; A.J. Fussell ; G.C. Clifton ; G.A. MacRae ; S.J. Hicks
- Book Title / Journal: New Zealand Society for Earthquake Engineering - Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Structure types ; Composite structures
- Keywords: composite deck ; diaphragm
- Description
- One of the most neglected elements in the design of buildings is the horizontal floor diaphragm and its interaction with the lateral load resisting systems. Most multi-story structures depend on the floor slab and roof systems to act as horizontal diaphragms to collect and distribute the lateral loads to the vertical framing members, which provide the overall structural stability.
In steel structures, floor diaphragms are most commonly constructed using composite steel deck with concrete fill, although other systems may also be used. Somewhat surprisingly, given the importance of diaphragms to the overall building response, there is no universally agreed design procedure for determining the diaphragm actions and distribution into the seismic-resisting systems. In addition, the specific issues related to beam design for members collecting lateral loads in composite floor systems has gone largely undocumented.
This discussion paper presents a suggested method in determining the design diaphragm actions at a given floor level, how to proportion their transfer into the seismic resisting systems and how to design and detail the supporting beams/composite metal deck for these actions.
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- Rocking steel shear walls with energy dissipation devices
- G.S. Djojo ; G.C. Clifton ; R.S. Henry
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Earthquake engineering
- Keywords: steel shear walls ; energy dissipation devices
- Description
- Conventional steel panel shear walls (SPSWs) comprise thin steel plates framed by beams and columns. These walls have been developed as ductile systems which resist seismic forces through a combination of shear resistance from the plates and flexural resistance from the frames. The internal shear forces in the plates are resolved into diagonal tension and compression principal stresses and after the compression diagonal buckles, the plates behave effectively as tension cross bracing. The ductile action is achieved through tensile yielding of the web plate and a plastic hinge is formed at the beam ends, with the columns expected to remain elastic. Although this system, under severe earthquakes, dissipates considerable energy through the yielding of selected members, structural damage with residual deformation may make repair difficult.
Therefore, an innovative steel panel shear wall is being developed by combining the advantages of the conventional wall system with a centralised rocking mechanism and energy dissipation devices to produce a lateral force resisting system with a low damage design solution that is intended to remain elastic during the rocking and expected to
return to original position after an ultimate limit state level earthquakes. During severe earthquakes, the columns move above or below the original position and the energy dissipation devices provide restoring forces to pull back the columns. A rocking base point at the bottom middle of the wall maintains the stability of the structure. This paper
presents the concept and numerical analysis of this wall focusing on the energy dissipation device system.
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- Development and research of eccentrically braced frames with replaceable active links
- A.J. Fussell ; K.A. Cowie ; G.C. Clifton ; N. Mago
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Earthquake engineering
- Keywords: eccentrically braced frames ; steel frames
- Description
- Ductile eccentrically braced frames designed in accordance with the New Zealand Steel Structures Standard, NZS 3404, provide life safety during a design level or greater earthquake; however, the eccentrically braced frame active link may sustain
significant damage through repeated inelastic deformation. This may necessitate postearthquake
replacement of the active link. A bolted replaceable active link can be used to facilitate replacement after a strong earthquake, which reduces repair costs.
New Zealand design guidance for the seismic design of steel eccentrically braced frames was first published in 1995 by the New Zealand Heavy Engineering Research Association within HERA Report R4-76 and has been widely used in practice. This guidance has been recently updated and now includes seismic design procedures for eccentrically
braced frames with replaceable links. This article covers the development and research of eccentrically braced frames with replaceable links. This includes discussions of the comprehensive research programme recently completed in Canada investigating the performance of eccentrically braced frames with replaceable links and finite element analysis undertaken by the New Zealand Heavy Engineering Research Association, to
verify the design procedure for eccentrically braced frames with replaceable links.
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- Non-destructive method to investigate the hardness - plastic strain relationship in cyclically deformed structural steel elements
- H. Nashid ; W.G. Ferguson ; G.C. Clifton ; M. Hodgson ; M- Battley ; C. Seal ; J.H. Choi
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Structure types ; Steel structures ; Non Destructive Testing
- Keywords: steel elements ; non-destructive method
- Description
- A non-destructive hardness testing method is being developed to determine plastic strain in steel elements that have been subjected to inelastic seismic loading. The focus of this study is on the active links of eccentrically braced frames (EBFs). The 2010/2011 Christchurch earthquake series, especially the very intense February 22 shaking, was the first earthquake worldwide to push complete EBF systems into their inelastic state, generating a moderate to high level of plastic strain in EBF active links for a range of buildings from 3 to 23 storeys in height. Plastic deformation was confined to the active links. This raised two important questions: 1) what was the extent of plastic deformation; and 2) what effect does that have on post-earthquake steel properties? To answer these questions a range of actions are being taken. A non-destructive hardness test method is being developed to determine a relationship between hardness and plastic strain in active link beams. Active links from the earthquake affected, 23-storey Pacific Tower building in Christchurch has been hardness and material property tested to determine the changes in the steel, and cyclic testing of active links to defined levels of inelastic demand is underway. Test results to date show clear evidence that the hardness based method is able to give a good relationship between hardness measurements and plastic strain. This paper presents recent significant findings from this project. Principal of these is the discovery that hot rolled steel tested beams, all carry manufacturing induced plastic strains, in regions of the webs, of up to 5%. It is the intention of the overall research project, to establish a robust relationship between measured hardness and plastic strain demand in cyclically deformed steel elements and a comprehensive guideline to assess commonly used seismic-resisting systems will be adopted.
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- Performance of eccentrically braced framed buildings in the Christchurch earthquake series of 2010/2011
- G.C. Clifton ; H. Nashid ; M. Hodgson ; C. Seal ; M. Bruneau ; G.A. MacRae ; S. Gardiner ; G. Ferguson
- The 15th World Conference on Earthquake Engineering, Lisbon, Portugal, Paper No. 2502
- Book Title / Journal:
- Year: 2012 , Volume: , Series:
- Earthquake engineering
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- Development of the self-centering sliding hinge joint.
- H.H. Khoo ; J. Butterworth ; C.D. Mathieson ; G.A. MacRae ; G.C. Clifton
- Proceedings of the Ninth Pacific Conference on Earthquake Engineering Building an Earthquake-Resilient Society, Auckland, New Zealand, Paper 106.
- Book Title / Journal:
- Year: 2011 , Volume: , Series:
- Earthquake engineering
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