Latest Publications

Description Category Date Author
Development and Research of Eccentrically Braced Frames with Replaceable Active Links

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 su...

EQK1005.pdf
Earthquake 24/04/2014 Alistair Fussell; Kevin Cowie; Charles Clifton; Nandor Mago
Eccentrically Braced Frames Lateral Restraint of Link Bottom Flange

Eccentrically braced frames are required to be laterally restrained at both the top and bottom of the active link member ends to ensure reliable performance in a seismic event. There are occasions when direct lateral restraint to the botto...

EQK1009.pdf
Earthquake 18/12/2013 Kevin Cowie; Alistair Fussell; Charles Clifton
Design of the Linked Column Frame Structural System - A New Zealand Application

The Link Column Frame (LCF) system is a brace free hybrid system combining proven seismic load resisting technology; eccentrically braced frames (EBF) with removable links and moment resisting frames (MRF). It was developed to meet the requ...

EQK1010.pdf
Earthquake 04/06/2013 Alistair Fussell, Peter Dusicka, Charles Clifton, Martin Wong
Eccentrically Braced Frames with Removable Links - Design Example

Steel eccentrically braced frames are expected to sustain damage during a design level earthquake through repeated inelastic deformation of the active link. A method for assessment of the extent of inelastic strain in the active link is cu...

EQK1007.pdf
Earthquake 03/03/2013 Kevin Cowie; Alistair Fussell
Eccentrically Braced Frames with Removable Links - Design Methodology

Steel eccentrically braced frames are expected to sustain damage during a design level earthquake through repeated inelastic deformation of the active link. Repair is therefore expected to be costly and disruptive, even if the structure ha...

EQK1006.pdf
Earthquake 16/01/2013 Kevin Cowie; Alistair Fussell; Martin Wong; Charles Clifton; Dmitry Volynkin
Design Example of Moment Resisting Seismic Frames with Reduced Beam Sections

The design of moment resisting seismic frames can by optimised with the use of reduced beam sections. In a reduced beam section (RBS) moment connection (figure 1), portions of the beam flanges are selectively trimmed in the region adjacent ...

EQK1004.pdf
Earthquake 09/07/2010 Kevin Cowie
Design Considerations and Benefits of Moment Resisting Seismic Frames with Reduced Beam Sections

The design of moment resisting seismic frames can by optimised with the use of reduced beam sections. In a reduced beam section (RBS) moment connection (Figure 1) portions of the beam flanges are selectively trimmed in the region adjacent t...

EQK1003.pdf
Earthquake 09/07/2010 Kevin Cowie
Research, Development and Design Rules of Moment Resisting Seismic Frames with Reduced Beam Sections

Structural design for large seismic events must explicitly consider the effects of response beyond the elastic range. The moment resisting seismic frame is designed to form beam plastic hinges near the face of the column. After the discover...

EQK1002.pdf
Earthquake 09/07/2010 Kevin Cowie
Steel Performance in the Padang Earthquake 2009

A M7.6 earthquake, with depth 80 km, occurred near Padang City, Sumatra, Indonesia on September 30, 2009. The overwhelming majority of the buildings damaged were reinforced concrete frames with unreinforced brick infill panels, reflecting t...

EQK1001.pdf
Earthquake 30/10/2009 Clark Hyland & Scott Miller
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Development and Research of Eccentrically Braced Frames with Replaceable Active Links

Written by Alistair Fussell; Kevin Cowie; Charles Clifton; Nandor Mago on April 24th, 2014.      0 comments

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 post-earthquake 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.
Topics: Coating Earthquake
 

Eccentrically Braced Frames Lateral Restraint of Link Bottom Flange

Written by Kevin Cowie; Alistair Fussell; Charles Clifton on December 18th, 2013.      0 comments

Eccentrically braced frames are required to be laterally restrained at both the top and bottom of the active link member ends to ensure reliable performance in a seismic event. There are occasions when direct lateral restraint to the bottom flange is not permitted. In this instance the lateral restraint of the bottom flange of the active link end can be achieved from minor axis bending of the brace. This article presents a simplified procedure for this approach by a way of a design example.
Topics: Coating Earthquake
 

Design of the Linked Column Frame Structural System - A New Zealand Application

Written by Alistair Fussell, Peter Dusicka, Charles Clifton, Martin Wong on June 4th, 2013.      0 comments

The Link Column Frame (LCF) system is a brace free hybrid system combining proven seismic load resisting technology; eccentrically braced frames (EBF) with removable links and moment resisting frames (MRF). It was developed to meet the requirement for continued occupancy, or at least rapid return to occupancy after a severe earthquake. This is a departure from the prevailing New Zealand seismic design approach pre the 2010/2011 Christchurch earthquake series which involves designing for controlled damage (energy dissipation) in selected elements of the seismic load resisting system which are typically not rapidly or cost effectively repaired. Engineers familiar with the design of EBF and MRF systems will readily understand and be able to apply the LCF frame structural system design concepts. The only departure from standard office practice is the requirement to undertake a non–linear push over analysis. As a result, practicing engineers will likely find the design methodology for this system easier to implement than those for some other low damage seismic load resisting solutions. Useful background information to the LCF system is found in the paper of Dusicka et. al.[1]. It is recommended this is read in conjunction with the present paper which is intended to illustrate the application of the capacity design principles of the Steel Structures Standard (NZS 3404 [2]) to this new system.
Topics: Coating Earthquake
 

Eccentrically Braced Frames with Removable Links - Design Example

Written by Kevin Cowie; Alistair Fussell on March 3rd, 2013.      0 comments

Steel eccentrically braced frames are expected to sustain damage during a design level earthquake through repeated inelastic deformation of the active link. A method for assessment of the extent of inelastic strain in the active link is currently being developed. Repair is therefore expected to be costly and disruptive, even if the structure has met its goal of providing life safety during an earthquake. The replaceable or removable active link concept addresses these drawbacks. It allows for quick inspection and replacement of damaged links following a major earthquake, significantly minimising the disruption of the structure. The development, research, design methodology and detailing considerations of eccentrically braced frames with removable links are covered in Steel Advisor articles EQK1005 and EQK1006 (the former is in preparation at the time of writing this article). This article illustrates the application of the proposed eccentrically braced frame with removable link design procedure by way of a design example. Understanding of the design of conventional eccentrically braced frames has been assumed. For those not familiar with the seismic behaviour and design of eccentrically braced frames reference should be made to HERA Report R4-76.
Topics: Coating Earthquake
 

Eccentrically Braced Frames with Removable Links - Design Methodology

Written by Kevin Cowie; Alistair Fussell; Martin Wong; Charles Clifton; Dmitry Volynkin on January 16th, 2013.      0 comments

Steel eccentrically braced frames are expected to sustain damage during a design level earthquake through repeated inelastic deformation of the active link. Repair is therefore expected to be costly and disruptive, even if the structure has met its goal of providing life safety during an earthquake. The replaceable or removable active link concept addresses these drawbacks as it allows for quick inspection and replacement of damaged links following a major earthquake, significantly minimising the time to reoccupy the building. The development and research of eccentrically braced frames with removable links is covered in Steel Advisor article EQK1005 (in preparation at the time of writing this article). This article presents the design methodology for eccentrically braced frames with removable links. It focuses on the design and detailing of the link, and where necessary, modifications to the design procedure for conventional EBF’s. Readers not familiar with the global seismic behaviour and design of eccentrically braced frames should consult HERA report R4-76. Steel Advisor article EQK1007 provides a worked design example to illustrate the application of the proposed eccentrically braced frame with removable link design procedure.
Topics: Coating Earthquake
 

Design Example of Moment Resisting Seismic Frames with Reduced Beam Sections

Written by Kevin Cowie on July 9th, 2010.      0 comments

The design of moment resisting seismic frames can by optimised with the use of reduced beam sections. In a reduced beam section (RBS) moment connection (figure 1), portions of the beam flanges are selectively trimmed in the region adjacent to the beam to column connection. Yielding and hinge formation are intended to occur primarily within the reduced section of the beam and there by limit the design actions and the inelastic deformation demands developed at the face of the column. The development, research, design rules, design consideration and benefits of the RBS are covered in previous Steel Advisor articles EQK1002 and EQK1003. This article illustrates the application of the RBS design rules by way of a design example.
Topics: Coating Earthquake
 

Design Considerations and Benefits of Moment Resisting Seismic Frames with Reduced Beam Sections

Written by Kevin Cowie on July 9th, 2010.      0 comments

The design of moment resisting seismic frames can by optimised with the use of reduced beam sections. In a reduced beam section (RBS) moment connection (Figure 1) portions of the beam flanges are selectively trimmed in the region adjacent to the beam to column connection. Yielding and hinge formation are intended to occur primarily within the reduced section of the beam and there by limit the design actions and the inelastic deformation demands developed at the face of the column. The development, research and design rules of this type of connection are discussed in a previous Steel Advisor article EQK1002. This article highlights some of the design considerations and benefits of using reduced beam sections with moment resisting seismic frames.
Topics: Coating Earthquake
 

Research, Development and Design Rules of Moment Resisting Seismic Frames with Reduced Beam Sections

Written by Kevin Cowie on July 9th, 2010.      0 comments

Structural design for large seismic events must explicitly consider the effects of response beyond the elastic range. The moment resisting seismic frame is designed to form beam plastic hinges near the face of the column. After the discovery of brittle fractures in steel moment frame welded connections in the 1994 Northridge earthquake in California, the reduced beam section (RBS) moment connection was developed and is now extensively used throughout North America and other parts of the world. The intent of the RBS is to move the plastic hinge region away from the face of the column (figure 2). This is accomplished by reducing the beam's actual plastic moment by removing part of the beam flange as shown in figure 1. This reduced section creates a weaker location where yielding and plastic hinge formation is expected to occur, and results in a reduced moment that develops at the face of the column. By reducing moment demands at the column face the beam-column connections and the column panel zone requirements are reduced. Further more, the use of RBS may also lead to smaller column sizes.
Topics: Coating Earthquake
 

Steel Performance in the Padang Earthquake 2009

Written by Clark Hyland & Scott Miller on October 30th, 2009.      0 comments

A M7.6 earthquake, with depth 80 km, occurred near Padang City, Sumatra, Indonesia on September 30, 2009. The overwhelming majority of the buildings damaged were reinforced concrete frames with unreinforced brick infill panels, reflecting the popularity of this form of construction in the affected area. However some important lessons can be learned from observations of the performance of the few steel structures affected. Two of these collapsed dramatically, tragically killing over 200 people.
Topics: Coating Earthquake
 
   
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