SESOC

Journals Abstracts

These are short abstracts of the material printed in our journal which is published twice annually. The Journal covers items of interest to structural engineers, including but not limited to: technical papers, project reports, materials information, code reviews.

Journal: Vol 24 No. 1 2011

 

Title
TESTING AND SEISMIC RETROFIT OF 1917 WINTEC F BLOCK URM BUILDING IN HAMILTON
Author/s

Yi-Wei Lin, Hossein DeRakhshan, Dmytro Dizhur, Ronald Lumantarna, Liam Wotherspoon and Jason M. Ingham
Abstract

Wintec F block is a two storey unreinforced masonry (URM) building constructed in 1917 with an architectural style termed “stripped classical”, that was assessed to be potentially earthquake prone according to the provisions of the Building Act 2004. Material testing and seismic assessment were conducted on the as-built structure and it was determined thatWintec F block had sufficient out-of-plane seismic strength for most of its walls, but that the building had insufficient in-plane seismic strength. Seismic improvement was proposed using a type of strain-hardening fibre reinforced shotcrete called Engineered Cementitious Composite (ECC) combined with steel reinforcement, and the building was strengthened to 100% of New Building Standard (NBS).
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Title
DESIGN OF FLOORS CONTAINING PRECAST UNITS IN MULTI-STOREY BUILDINGS
Author/s

Richard Fenwick, Des Bull and Peter Moss
Abstract

As a result of research carried out in the last decade methods of detailing hollow-core and other forms of precast units in floors have been developed to overcome a number of weaknesses, which have been observed in structural tests and predicted in analytical studies. This work has lead to a number of changes being introduced into the Structural Concrete Standard, NZS 3101: 2006 with Amendment 2. The intent behind this paper is to identify and describe the specific aspects that should be addressed by structural designers for floors containing precast units, and to identify the relevant clauses in the Structural Concrete Standard. In addition guidance is given on aspects of behaviour that are not currently covered by the Standard. The paper does not consider methods of assessing diaphragm forces induced in floors by seismic or wind forces.
SESOC Members click here to download - Non Members click here


Title
SEISMIC BEHAVIOUR OF STEEL MOMENT FRAMES WITH AN INNOVATIVE SLOTTED-BOLTED CONNECTION IN NEAR FIELD EARTHQUAKES BASED ON ENERGY
Author/s

Mehdi Torabi and Mohsen Tehranzadeh
Abstract

Input energy and the ratio of hysteretic to input energy could be regarded as criteria to evaluate the performance of a structure during a seismic event. With regard to the significance of employment of slotted bolted connections in seismic design of steel moment frames, a new type of them has been introduced. Subsequently, the seismic performances of steel moment frames with/without the proposed connection subjected to near field earthquake excitations have been compared by means of energy concepts. Nonlinear dynamic analyses were made using three far field and three near field records through PERFORM platform. Moreover, the effects of the number of stories and bays as well as Peak Ground Acceleration (hereafter PGA) of earthquake record were studied. The results show that the performance of steel moment frames with the proposed connection subjected to near field as well as far field earthquakes are more dependable compared to those of customary steel moment frames on the basis of energy criteria.
SESOC Members click here to download - Non Members click here


Title
Letter to the Editor_Travel to IDEERS Seismic Design Competition in Taiwan Vol 24 No 1
Author/s

John O’Hagan, Felix Scheibmair, Tim Swager and Hsen-Han Khoo
Abstract

First and foremost, we would like to extend our thanks to the Structural Engineering Society for providing sponsorship for our team to attend the 2010 postgraduate IDEERS seismic design competition in Taiwan. Without your generous support we would not have been able to attend the competition, from which we have all increased our earthquake engineering knowledge.
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Title
Letter to the Editor_Boundary Wall Surcharges in Auckland Vol 24 No 1
Author/s

Tom Lanigan
Abstract

I am responding to your editorial in the March 2010 SESOC journal. In this journal you wrote a short dissertation on boundary walls whereby you queried a number of issues surrounding the design of boundary walls. The following is my understanding of the situation.
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Title
22 February Christchurch Earthquake_Questions Regarding the Design Process Vol 24 No 1
Author/s

Greg McRae
Abstract

Greg McRae (University of Canterbury) has shared some questions with us regarding the 22 February earthquake which had a devastating effect on Christchurch. These questions need answering before we can move on with the reconstruction work with confidence. We also refer you to the SESOC website where you can comment online to a number of questions which require some healthy debate – Editor.
SESOC Members click here to download - Non Members click here


Title
Forsyth Barr Stadium – Dunedin, NZ_A New Fully Roofed Rugby Stadium for Otago Vol 24 No1
Author/s

Trevor W. Robert son
Abstract

Otago desired a new rugby stadium to replace the existing Carisbrook Park, colloquially known as “The House of Pain” due to the sometimes severe winter weather that could plague major tournaments. New Zealand Rugby Football Union winning the rights to the 2011 Rugby World Cup provided the catalyst for this project to get under way. To be constructed on a new site close to the city, the new stadium was to be fully roofed, but needed to avoid the costs associated with opening sections and the like. The solution developed was for a relatively low transparent roof angled for beneficial transmission of sunlight to the turf. The region is subject to significant wind, seismic actions and to sub-alpine snow fall. These factors lead to a challenging project. This paper describes those challenges and the solutions developed.
SESOC Members click here to download - Non Members click here


Title
A Pilot Survey of Structural Engineers’ Perceptions Regarding Specification of Laminated Veneer Lumber in Single-Storey Industrial Buildings Vol 24 No 1
Author/s

Robert McGregor, David Evison and Lucie Ozanne
Abstract

A pilot survey of Christchurch structural engineers was carried out between November 2009 and February 2010, to examine factors affecting the specification of laminated veneer lumber (LVL) for single-storey industrial buildings. Single-storey industrial buildings were chosen for study because they are a significant proportion of the workload of most civil and structural engineering firms in Christchurch, the specification of materials is done by the engineer, and currently steel is the preferred structural material for this type of building. The survey was designed to answer the following questions: 1. What are engineers’ perceptions regarding specification of LVL in single-storey industrial buildings? 2. What barriers prevent increased use of LVL in this application? 3. How do engineers rate LVL compared with steel on factors which determine usage?
SESOC Members click here to download - Non Members click here


Title
Retrofit Techniques for Seismic Improvement of URM Buildings Vol 24 No 1
Author/s

Cass Goodwin, Garry Tonks and Jason Ingham
Abstract

There are many complex considerations when seeking to seismically retrofit unreinforced masonry (URM) buildings. Strength requirements need to be evaluated, and the intrinsic strength of the existing materials should be maximised before adding any additional structure. Descriptions of current common techniques for improving the seismic response of URM buildings are outlined, and comments made as to their general appropriateness with regard to architectural and heritage principles. These techniques are explained and critiqued using examples to illustrate their merits or lack thereof.
SESOC Members click here to download - Non Members click here


Title
Testing and Seismic Retrofit of 1917 Wintec F Block URM Building in Hamilton Vol 24 No 1
Author/s

Yi-Wei Lin, Hossein Derakhshan, Dmytro Dizhur, Ronald Lumantarna, Liam Wotherspoon And Jason M. Ingham
Abstract

Wintec F block is a two storey unreinforced masonry (URM) building constructed in 1917 with an architectural style termed “stripped classical”, that was assessed to be potentially earthquake prone according to the provisions of the Building Act 2004. Material testing and seismic assessment were conducted on the as-built structure and it was determined that Wintec F block had sufficient out-of-plane seismic strength for most of its walls, but that the building had insufficient in-plane seismic strength. Seismic improvement was proposed using a type of strain-hardening fibre reinforced shotcrete called Engineered Cementitious Composite (ECC) combined with steel reinforcement, and the building was strengthened to 100% of New Building Standard (NBS).
SESOC Members click here to download - Non Members click here


Title
Tentative Seismic Design Guidelines for Rocking Structures Vol 24 No 1
Author/s

Trevor E Kelly
Abstract

Many new and existing buildings have insufficient weight to resist overturning loads due to earthquakes without uplift. Previous versions of the New Zealand loadings code allowed simplified procedures for the design of rocking structures provided the ductility factor was limited to not more than two. The new loadings code, NZS 1170.5, removed this exemption and requires that a special study be performed whenever energy dissipation through rocking occurs. This paper presents a tentative design procedure intended to substitute for the special study required by the code. The resistance function of rocking walls was developed from the principles of engineering mechanics. The results from a series of time history analyses were used to develop a procedure to estimate maximum seismic displacements and empirical equations were derived to estimate the dynamic amplification of inertia forces. A substitute structure approach, using spectral displacements at an effective period calculated from the ductility factor, provided accurate predictions of the displacements from more sophisticated nonlinear analyses. Four example designs were completed and the predicted response compared to time history results. The procedure provided a satisfactory estimate of response for regular structures, but it was less accurate where torsional effects were significant.
SESOC Members click here to download - Non Members click here


Title
Design of Floors Containing Precast Units in Multi-Storey Buildings Vol 24 No 1
Author/s

Richard Fenwick, Des Bull and Peter Moss
Abstract

As a result of research carried out in the last decade methods of detailing hollow-core and other forms of precast units in floors have been developed to overcome a number of weaknesses, which have been observed in structural tests and predicted in analytical studies. This work has led to a number of changes being introduced into the Structural Concrete Standard, NZS 3101: 2006 with Amendment 2. The intent behind this paper is to identify and describe the specific aspects that should be addressed by structural designers for floors containing precast units, and to identify the relevant clauses in the Structural Concrete Standard. In addition guidance is given on aspects of behaviour that are not currently covered by the Standard. The paper does not consider methods of assessing diaphragm forces induced in floors by seismic or wind forces.
SESOC Members click here to download - Non Members click here


Title
Seismic Behaviour of Steel Moment Frames with an Innovative Slotted-Bolted Connection in Near Field Earthquakes Based on Energy Vol24No 1
Author/s

Mehdi Torabi and Mohsen Tehranzadeh Dept of Civil & Environmental Engineering, Amirkabir U of Technology, Tehran, Iran
Abstract

The steel moment frame with fully restrained (FR) connections is a very popular type of seismic load resistance system worldwide. Several post-earthquake reconnaissances have revealed some weaknesses associated with welded FR connections. The great expense which needs to be spent on the repair of such systems is one of their main drawbacks. This leads to the idea of “damage avoidance design” to become more highlighted among structural engineering communities. Moreover, observed responses of the damaged steel frames in the 1994 Northridge and the 1995 Hyogoken Nanbu earthquakes show that the connection’s behaviour has switched from initially rigid to semi-rigid during ground motion. On the other hand, the overall Abstract Input energy and the ratio of hysteretic to input energy could be regarded as criteria to evaluate the performance of a structure during a seismic event. With regard to the significance of employment of slotted bolted connections in seismic design of steel moment frames, a new type of them has been introduced. Subsequently, the seismic performances of steel moment frames with/without the proposed connection subjected to near field earthquake excitations have been compared by means of energy concepts. Nonlinear dynamic analyses were made using three far field and three near field records through PERFORM platform. Moreover, the effects of the number of stories and bays as well as Peak Ground Acceleration (hereafter PGA) of earthquake record were studied. The results show that the performance of steel moment frames with the proposed connection subjected to near field as well as far field earthquakes are more dependable compared to those of customary steel moment frames on the basis of energy criteria.
SESOC Members click here to download - Non Members click here


Title
FORSYTH BARR STADIUM – DUNEDIN, NEW ZEALAND A NEW FULLY ROOFED RUGBY STADIUM FOR OTAGO Vol 24 No 1
Author/s

Trevor W. Robertson
Abstract

Otago desired a new rugby stadium to replace the existing Carisbrook Park, colloquially known as “The House of Pain” due to the sometimes severe winter weather that could plague major tournaments. New Zealand Rugby Football Union winning the rights to the 2011 Rugby World Cup provided the catalyst for this project to get under way. To be constructed on a new site close to the city, the new stadium was to be fully roofed, but needed to avoid the costs associated with opening sections and the like. The solution developed was for a relatively low transparent roof angled for beneficial transmission of sunlight to the turf. The region is subject to significant wind, seismic actions and to sub-alpine snow fall. These factors lead to a challenging project. This paper describes those challenges and the solutions developed.
SESOC Members click here to download - Non Members click here


Title
22 FEBRUARY CHRISTCHURCH EARTHQUAKE Vol 24 No 1
Author/s

Greg McRae
Abstract

GREG McRae (University of Canterbury) has shared some questions with us regarding the 22 February earthquake which had a devastating effect on Christchurch. These questions need answering before we can move on with the reconstruction work with confidence. We also refer you to the SESOC website where you can comment online to a number of questions which require some healthy debate.
SESOC Members click here to download - Non Members click here


Title
A PILOT SURVEY OF STRUCTURAL ENGINEERS’ PERCEPTIONS REGARDING SPECIFICATION OF LAMINATED VENEER LUMBER IN SINGLE-STOREY INDUSTRIAL BUILDINGS Vol 24 No 1 2011
Author/s

Robert McGregor, David Evison and Lucie Ozanne
Abstract

A pilot survey of Christchurch structural engineers was carried out between November 2009 and February 2010, to examine factors affecting the specification of laminated veneer lumber (LVL) for single-storey industrial buildings. Single-storey industrial buildings were chosen for study because they are a significant proportion of the workload of most civil and structural engineering firms in Christchurch, the specification of materials is done by the engineer, and currently steel is the preferred structural material for this type of building.
SESOC Members click here to download - Non Members click here


Title
RETROFIT TECHNIQUES FOR SEISMIC IMPROVEMENT OF URM BUILDINGS Vol 24 No 1 2011
Author/s

Cass Goodwin, Garry Tonks and Jason Ingham
Abstract

There are many complex considerations when seeking to seismically retrofit unreinforced masonry (URM) buildings. Strength requirements need to be evaluated, and the intrinsic strength of the existing materials should be maximised before adding any additional structure. Descriptions of current common techniques for improving the seismic response of URM buildings are outlined, and comments made as to their general appropriateness with regard to architectural and heritage principles. These techniques are explained and critiqued using examples to illustrate their merits or lack thereof.
SESOC Members click here to download - Non Members click here


Title
TENTATIVE SEISMIC DESIGN GUIDE- LINES FOR ROCKING STRUCTURES Vol 24 No 1 2011
Author/s

Trevor E Kelly
Abstract

Many new and existing buildings have insufficient weight to resist overturning loads due to earthquakes without uplift. Previous versions of the New Zealand loadings code allowed simplified procedures for the design of rocking structures provided the ductility factor was limited to not more than two. The new loadings code, NZS 1170.5, removed this exemption and requires that a special study be performed whenever energy dissipation through rocking occurs. This paper presents a tentative design procedure intended to substitute for the special study required by the code. The resistance function of rockingwallswas developed fromthe principles of engineering mechanics. The results from a series of time history analyses were used to develop a procedure to estimate maximum seismic displacements and empirical equations were derived to estimate the dynamic amplification of inertia forces. A substitute structure approach, using spectral displacements at an effective period calculated from the ductility factor, provided accurate predictions of the displacements from more sophisticated nonlinear analyses. Four example designs were completed and the predicted response compared to time history results. The procedure provided a satisfactory estimate of response for regular structures, but it was less accurate where torsional effects were significant.
SESOC Members click here to download - Non Members click here


 

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