211 results for Ingham, Jason, Conference item

  • Assessment of timber floor diaphragms in historic unreinforced masonry buildings

    Wilson, AW; QUENNEVILLE, PJH; Ingham, Jason (2011)

    Conference item
    The University of Auckland Library

    Unreinforced masonry (URM) buildings outside of Europe were typically constructed with rigid clay brick perimeter walls, and comparatively flexible timber floor diaphragms. URM construction represents the predominant architectural heritage of many nations but the preservation of these buildings in seismically active regions is threatened due their well established inadequacy to withstand earthquakes. Timber floor diaphragms are widely recognized to have significant impact on the overall seismic response of URM structures, and the accurate assessment of diaphragms is therefore crucial during the seismic assessment and retrofit of URM buildings. NZSEE (2006) - Assessment and improvement of the structural performance of buildings in earthquakes, and ASCE 41-06 (2007) – Seismic rehabilitation of existing buildings represent the current state-of-the-art in seismic assessment but the validity of the procedures associated with timber diaphragm performance remains uncertain, and a review of their application and accuracy is required. As part of a wider research program, a series of full-scale diaphragm tests were performed to generate the much needed data to critique the current desktop procedures. In this contribution, the NZSEE and ASCE 41-06 procedures are used to predict full-scale diaphragm performance and are compared against experimentally determined values. It was found that inconsistency exists between the two assessment documents with considerable differences found in strength, stiffness and ductility predictions. The procedures published in NZSEE and ASCE 41-06 require updated and representative values, and to include provisions to address the highly orthotropic nature of diaphragms that was identified from testing. It is also believed that these documents should be harmonized to ensure that transparency and consistency exists between international assessment procedures.

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  • Cyclic out-of-plane behaviour of post-tensioned clay brick masonry

    Ismail, N; Laursen, PT; Schultz, AE; Ingham, Jason (2011-06-05)

    Conference item
    The University of Auckland Library

    Out-of-plane flexural testing of three (03) full scale unreinforced masonry (URM) walls seismically retrofitted using post-tensioning is reported. The selected wall configurations were representative of common URM walls that were vulnerable to out-of-plane failure, and imitated heritage URM construction by using salvaged clay brick masonry and ASTM type O mortar. Varying levels of pre-compression were applied to the test walls using a single mechanically restrained tendon inserted into a cavity at the centre of each test wall. Behaviour of the post-tensioned URM walls was compared to the response of a non-retrofitted URM wall, with the out-of-plane flexural strength of the post-tensioned masonry walls observed to range from 2.9 to 10.3 times the strength of the non-retrofitted URM wall. Several aspects pertaining to the seismic behaviour of post-tensioned masonry walls were investigated, including tendon stress variation, damage patterns, force-displacement behaviour, initial stiffness, and displacement capacity. Test results were compared with equations developed in previous studies, and it was established that the walls that were post-tensioned using seven-wire strands had measured strengths that compared favourably with predicted values, whereas the wall that was post-tensioned using mild steel bar had failed at a lower measured strength than the predicted value.

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  • Trends in the Architectural Characterisation of Unreinforced Masonry in New Zealand

    Russell, Alistair; Ingham, Jason (2008)

    Conference item
    The University of Auckland Library

    This paper identifies seven typologies for characterising New Zealand’s unreinforced masonry (URM) building stock. This enables a better understanding of what typical behaviour to expect when assessing heritage URM buildings. Distinctions between typologies are drawn largely on the basis of building height and the geometry of the building’s footprint.

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  • Modelling the Flushing Mechanism of Thin Flexible Surfaced Pavements in New Zealand

    Kodippily, Sachi; Henning, Theunis; Ingham, Jason; CENEK, P (2010)

    Conference item
    The University of Auckland Library

    Flushing is a major cause of maintenance on chipsealed pavements in New Zealand. Accurate understanding of flushing can have a significant impact in terms of predicting future maintenance needs, expenditure, and performance of pavements. Currently available literature does not provide sufficient information to gain a mechanistic understanding of this defect. Therefore, developing a flushing forecasting model remains a priority for the road asset management sector in New Zealand. The reported research aimed to develop a mechanistic understanding of the processes involved with the flushing defect. The study primarily focused on identifying methods that can be used to investigate the particular mechanisms causing flushing on pavements based on network level data. Twenty five pavement sites on state highways of Napier/ Hawke’s Bay region of New Zealand were identified, with top surface lives ranging from three to nine years. Historical pavement data from these sites were analysed and the results combined with analysis of Long-Term Pavement Performance data to identify the main mechanisms causing flushing on chipsealed pavements. Surface depth and roughness were found to have the greatest influence on flushing, while surface texture measured by sand circles was found to be a satisfactory indicator of probable flushed chipseals. It is intended that these findings will contribute to the development of the flushing forecasting model for chipsealed pavements in New Zealand.

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  • Digital buildings: Using sensors to monitor the performance of concrete buildings during the Christchurch earthquake rebuild

    Simkin, Gye; Ingham, Jason (2014-06-11)

    Conference item
    The University of Auckland Library

    Following the devastation of the Canterbury earthquake sequence a unique opportunity exists to rebuild and restructure the city of Christchurch, ensuring that its infrastructure is constructed better than before and is innovative. By installing an integrated grid of modern sensor technologies into concrete structures during the rebuild of the Christchurch CBD, the aim is to develop a network of self-monitored ‘digital buildings’. A diverse range of data will be recorded, potentially including parameters such as concrete stresses, strains, thermal deformations, acoustics and the monitoring of corrosion of reinforcement bars. This procedure will allow an on-going complete assessment of the structure’s performance and service life, both before and after seismic activity. The data generated from the embedded and surface mounted sensors will be analysed to allow an innovative and real-time health monitoring solution where structural integrity is continuously known. This indication of building performance will allow the structure to alert owners, engineers and asset managers of developing problems prior to failure thresholds being reached. A range of potential sensor technologies for monitoring the performance of existing and newly constructed concrete buildings is discussed. A description of monitoring work conducted on existing buildings during the July 2013 Cook Strait earthquake sequence is included, along with details of current work that investigates the performance of sensing technologies for detecting crack formation in concrete specimens. The potential market for managing the real-time health of installed infrastructure is huge. Civil structures all over the world require regular visual inspections in order to determine their structural integrity. The information recorded during the Christchurch rebuild will generate crucial data sets that will be beneficial in understanding the behaviour of concrete over the complete life cycle of the structure, from construction through to operation and building repairs until the time of failure.

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  • Bridge Knee Joint with Headed Reinforcement

    Ingham, Jason; Priestley, Nigel; Seible, F (1995)

    Conference item
    The University of Auckland Library

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  • The Seismic Behaviour of Reinforced Concrete Beam-Column Knee Joints for Buildings

    Megget, Leslie; Ingham, Jason (1996)

    Conference item
    The University of Auckland Library

    This paper describes the cyclic testing of two half-scale reinforced concrete beam-column building knee joints designed to the 1995 New Zealand Concrete Standard, NZS 3101 (1995). The two knee joints were identical, except that one had a standard hook detail for the beam bottom bars and column internal bars while the other unit had beam and column U-bars in the joint region. Both units approached their nominal strengths under both opening and closing bending moments. The hooked unit developed a joint shear failure at displacement ductilities greater than 4, while the U-bar unit was able to form a reversing beam plastic hinge with little joint deterioration, although some joint cover concrete was lost. The maximum levels of joint shear sustained in these two units approached 0.1 f MPa, this being only half of the limiting joint shear stress specified in the NZ Concrete Standard.

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  • A Masonry Design Standard for Use in Developing Countries

    Ingham, Jason (2000)

    Conference item
    The University of Auckland Library

    This paper seeks to demonstrate how a recently released design standard for concrete masonry buildings not requiring specific engineering design, NZS 4229:1999, has application not only in a New Zealand context, but that with very minor modification would readily serve as an appropriate design document in many developing countries. Research conducted in support of the document is briefly discussed, as is the composition of the standard and a supporting document containing several design examples. Key features of the design process are discussed, and changes necessary in order to use the document in other countries are detailed.

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  • Seismic Performance of Two Reinforced Concrete Knee Joints Designed to the 1995 Concrete Standard

    Megget, Leslie; Ingham, Jason (1996)

    Conference item
    The University of Auckland Library

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  • Seismic Characterisation of Unreinforced Masonry Buildings in Auckland, New Zealand

    Walsh, Kevin; Cummuskey, P; Dizhur, Dmytro; Ingham, Jason (2014-07-07)

    Conference item
    The University of Auckland Library

    The 2010-2011 Canterbury earthquakes and corresponding Royal Commission reports have resulted in changes to the legislative environment and led to increased public awareness in New Zealand of the earthquake performance of unreinforced masonry (URM) buildings. As a result, building regulators, owners, tenants, users, and heritage advocates will be facing a unique challenge in the near future where improvements and demolitions of URM buildings are expected to occur at an unusually high rate. Auckland is the largest city in New Zealand, and because of the relative prosperity of Auckland during the period 1880-1930 when most URM buildings were being constructed in New Zealand, the city has the greatest stock of URM buildings in the country. Identifying those buildings most at risk in Auckland’s large and varied building stock has warranted a rapid field assessment programme supplemented by strategically chosen detailed assessments. Information that can be procured through rapid field inspections includes the building geometric typologies (e.g., heights, building footprint geometry, isolated versus row configuration, and the relationship of these factors to pounding potential), elevation type (e.g., perforated frame versus solid wall), presence of bond beams, wall construction (e.g., solid versus cavity, number of leafs), bond patterns, and basic construction material type (e.g., clay brick versus stone). Furthermore, investigation into the architectural history, heritage status, functional use, and perceived social/community value of Auckland’s URM buildings will affect the direction of retrofit strategies and priorities. As the owner of a large and varied portfolio of URM buildings as well as the local organisation responsible for assessing building safety, Auckland Council is developing exemplar inspection, assessment, and prioritisation strategies that will target the risks associated with URM buildings, in particular, so as to preserve and enhance safety, and the economic and community value of these special buildings.

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  • Agent-Based Modelling, a Quiet Revolution in Asset Management

    Bush, Simon; Henning, T; Ingham, Jason; Raith, Andrea (2014-06-26)

    Conference item
    The University of Auckland Library

    Over the past 20 years sophisticated technical models of the asset management process have been created, but asset management is a socio-technical process with the interaction between the social and technical systems directly impacting strategy development and the long-term evolution of the asset. To combine both the social and technical systems into one model a small number of researchers have started to use agent-based modelling. By creating these models, stakeholders’ reactions to proposed policies can be explored prior to policy implementation. This ability to explore stakeholder reactions means that, for the first time, asset management strategies can be developed that meet stakeholder expectations, while ensuring the on-going functionality of the asset. This paper provides an introduction to this new modelling technique. This paper also describes how agent-based models can be used to improve performance measurement and management, thus creating a framework for improved decision making.

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  • Damage to concrete structures from the 2010 Darfield (Canterbury, NZ) earthquake

    Ingham, Jason; Wotherspoon, L; Hogan, L; Ragued, B (2010)

    Conference item
    The University of Auckland Library

    The 2010 M7.1 Darfield earthquake was the largest natural disaster to occur in New Zealand since the 1931 Hawke’s Bay earthquake and caused extensive liquefaction and ground spreading, which led to damage to a large number of residential buildings. This damage was particularly significant because of the number of families that had to evacuate their homes, and because of the extensive cost of remediation to these homes. Underground concrete water and wastewater services were significantly damaged, and concerns were raised that water supplies were contaminated, such that bottled water was necessary. Extensive damage occurred to many unreinforced masonry buildings, but damage to concrete buildings was minor, and was attributed to poor seismic detailing. Damage to concrete bridges was primarily associated with spreading of bridge abutments and damage to bridge approaches, and only eight vehicle bridges were closed. Damage to the concrete wharfs at Lyttelton Port was also primarily attributable to ground spreading, and whilst remediation will be expensive, the port was able to remain fully operational. Overall, concrete structures performed very well in the earthquake.

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  • Unbonded prestressed panel tendon stress at in-plane nominal flexural strength

    Wight, Gavin; Russell, Alistair; Ingham, Jason (2006)

    Conference item
    The University of Auckland Library

    Accurate estimation of stress in unbonded tendons at the nominal strength limit state is essential for calculating the in-plane strength of unbonded post-tensioned wall panels. The study presented here was originally conducted for concrete masonry, and is currently being extended to include verification for precast concrete. International masonry and concrete design codes and standards provide varying equations for calculating unbonded tendon stress at the nominal strength limit state but in no case have these equations been verified for in-plane loading of walls. A finite element model validated against large-scale structural testing of post-tensioned concrete masonry walls is used in this paper to demonstrate the accuracy of these existing equations. A revised equation is then shown to provide the most accurate predictions of tendon stress for walls loaded in-plane and is recommended for inclusion in the masonry design standards NZS 4230. Subject to the results of current testing, it is expected that the equation shall prove equally suitable for inclusion in NZS 3101 also. The paper concludes by summarising the complete procedure for predicting the inplane response of post-tensioned masonry walls.

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  • Shake Table Testing of Post-tensioned Concerete Masonry Walls

    Wight, Gavin; Ingham, Jason; Kowalsky, MJ (2004)

    Conference item
    The University of Auckland Library

    Six single-storey unbonded post-tensioned concrete masonry (PCM) walls were tested on a single dimension shake table at North Carolina State University. The principal intent of this study was to validate the use of PCM for residential construction, before the first PCM house is built in New Zealand. Three rectangular walls were tested to demonstrate the seismic performance of post-tensioned rocking walls, followed by walls containing a door and window opening and a shrinkage control joint. A detailed account of wall construction, test setup, testing procedure and test results are provided in this paper.

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  • Structural seismic attributes of Auckland’s commercial building stock

    Walsh, Kevin; Cummuskey, PA; Dizhur, Dmytro; Ingham, Jason (2014-03-21)

    Conference item
    The University of Auckland Library

    As part of past hazard modelling projects in New Zealand, pilot studies have been performed to determine building typological information relevant to structural engineers and seismological hazard researchers. Relevant typological information includes construction material, structural configuration, age of the structure, number of stories, as well as the presence of structural vulnerabilities including parapets, geometric irregularities, pounding potential, and short column effects. The procurement of such typological information permits risk modellers to compose more accurate simulations, structural engineers to develop assessment and retrofit techniques for prototypical buildings, and for large asset owners to more precisely evaluate their risk profiles in comparison to the total building population. However, these studies have often been limited by the availability of structural plans and specifications and, in particular, efficient database storage of such relevant information on a large scale. Hence, many of these pilot studies have consisted mostly of visual inspections from street walks in a few specific cities within the country, with the data then being extrapolated to other cities in proportion to census data and commercial real estate figures. As territorial authorities, government agencies, and other large asset owners are responding to regulatory and market forces in the wake of the 2010-2011 Canterbury earthquakes to assess and retrofit buildings determined to be particularly vulnerable to earthquakes, an opportunity exists to expand upon the knowledge of structural typologies within New Zealand’s commercial building stock. Two departments at Auckland Council – Building Control and Property – are currently engaging in proactive efforts to assess thousands of commercial and industrial buildings across the Auckland region. Auckland is expected to have the most varied building stock containing representative examples of nearly all types of buildings throughout New Zealand given that it houses one-third of the country’s population and has been isolated from major, infrastructure-destroying earthquakes such as other major New Zealand population centres have experienced in the past 150 years that have subsequently resulted in those areas having more homogenous building stocks today.

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  • Experimental evaluation of inter-storey drifts during the Cook Strait earthquake sequence

    Ma, Tsun Ming Quincy; Beskhyroun, Sherif; Simkin, Gye; Wotherspoon, Liam; Ingham, Jason; Cole, G; Gebreyohaness, A; Sharpe, R (2014-03-21)

    Conference item
    The University of Auckland Library

    Building interstorey drifts remain to be the most direct and accurate indicator of damage potential during earthquakes. However, interstorey drifts are often difficult to measure due to the lack of an absolute frame of reference. Currently, numerical integration of acceleration data is the most commonly used technique to experimentally determine interstorey drifts in real buildings. This technique is very sensitive to low frequency errors and requires high quality acceleration data. Traditionally, buildings are rarely instrumented and consequently actual building acceleration and displacement data are rare. With recent advances in computing processing power, sensor and data transmission technologies, it has now become accessible for buildings to be densely instrumented and continuously monitored for vibration. This paper presents interstorey drift estimates of a midrise building in Wellington during the Cook Strait earthquake sequence. A number of different interstorey drift estimation algorithms were applied carefully. They produced very similar predictions and enabled displacement profiles to be predicted.

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  • Research on Multi-Storey Post-Tensioned Concrete Masonry Walls

    Laursen, Peter; Ingham, Jason (2001)

    Conference item
    The University of Auckland Library

    This paper describes the structural testing of two 3-storey high unbonded post-tensioned concrete masonry (PCM) cantilever walls. The 67% scale wall units were designed to model a typical cantilever wall from a 4-5 storey high office or apartment building. A detailed account of the wall design, test setup and testing procedure is provided along with preliminary results for wall unit 1.

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  • Determining the chloride resistance of ECC shotcrete

    Lin, Y.W.; Scott, A; Lawley, D; Wotherspoon, L; Ingham, Jason (2011)

    Conference item
    The University of Auckland Library

    Engineered cementitious composite (ECC) shotcrete is a sprayable cement composite reinforced with synthetic fibres that exhibits a strain-hardening characteristic when subjected to load. The ductile behaviour of ECC makes it an ideal repair material for concrete structures as the strains from expansion of the original concrete structure can be accommodated. Three tests were conducted to assess ECC’s performance in resisting chloride ions and thereby determining its suitability as a repair material for concrete structures exposed to marine environments. The three tests conducted determined the total accessible voids, capillary suction rate and chloride diffusion coefficient of the material. Six variations of ECC mix designs (including a standard ECC mix with specified compression strength of 40 MPa) were tested as well as a 40 MPa concrete. The results showed that a standard ECC shotcrete had a significant improvement in chloride resistance when compared to the 40 MPa concrete. The chloride resistance further improved when a metallic soap additive was added to the ECC mix. It was concluded that ECC is a suitable repair material for concrete structures exposed to marine environments.

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  • Overview of a Cement-stabilised Flax-fibre Reinforced Rammed Earth (Uku) Building System for New Zealand Indigenous Communities

    Cheah, Jing; Ingham, Jason; Morgan, Te Kipa (2008)

    Conference item
    The University of Auckland Library

    This paper outlines research that has been undertaken to create an accessible, low-cost, sustainable earthen building solution for Maori (the indigenous people of New Zealand) living in rural communities. Many individuals and families in rural Maori communities live in overcrowded dwellings with a low, inadequate standard of living. Reasons for the poor housing condition that exists can be attributed to legal issues regarding `Maori land` and land ownership, the urbanization of Maori, and the financial cost of constructing on isolated, undeveloped Maori land. In July 2003, a four year research grant was awarded to develop a low-cost flax-fibre reinforced rammed earth housing concept into a commercially viable building technology. An important measure of the value of the research was the ability of rural Maori communities to be able to use the outputs of the research directly. Consequently a community reference group was created comprising of representatives from potential Maori user groups/areas. During the research, an optimized Uku soil mix was determined comprising of 8% cement and 0.075% flax fibres. Material tests have also been conducted to determine the lower 5% compressive, flexural and shear design strengths of the material. The construction process was optimized throughout the research with the development of such devices as a mobile flax stripper and a custom-made formwork system. Improvements in construction methodology were also implemented. The research concluded in April 2008, with the construction of a full-size Uku house on the foreshore of Lake Rotoiti. This research has resulted in the development of a technology that rural Maori communities can immediately benefit from and has created a platform for future research and development of the Uku building system.

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  • A Presentation of the PRESSS Technology applied to a 39-storey building by Pankow Builders in California

    Ingham, Jason (2000)

    Conference item
    The University of Auckland Library

    This paper reviews technology transfer related to structural testing of precast post-tensioned concrete construction. The background research is briefly reviewed, with attention then given to a number of recently constructed structures utilising precast post-tensioned concrete moment-resisting frames, and built by Pankow Builders Ltd. Emphasis is given to details of a 39-storey concrete frame structure in San Francisco, California, which when completed will be the tallest concrete structure in the highest seismicity zone of California. It is concluded that there are no technical barriers to transfer of this technology to New Zealand.

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