326 results for Ingham, Jason

  • A Case Study of Successful Performance of Retrofitted Masonry Substations

    Misnon, Noor Aina; Dizhur, Dmytro; Mackenzie, John; Fikri, Rijalul; Abeling, Shannon; Ingham, Jason (2016)

    Conference Contributions - Other
    University of Canterbury Library

    Since the mid 1990s, the Christchurch inventory of substation buildings was seismically retrofitted as part of the Risk and Realities improvement programme. • The substation buildings were retrofitted using a system of simple and cost-effective steel elements. • The 2010/2011 Canterbury earthquakes caused significant immediate disruption to power distribution network in Christchurch. • It took a single day in September 2010 and ten days in February 2011 to restore power to 90% customers. Tostudytheseismicperformanceofmasonrysubstationbuildingsfromamulti-disciplinary perspective on structural,economic and social aspects.

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  • SEISMIC STRENGTHENING OF REINFORCED CONCRETE COLUMNS WITH STRAIGHT CARBON FIBRE REINFORCED POLYMER (CFRP) ANCHORS

    Ingham, Jason; Griffith, Michael; del Rey Castillo, Enrique (2016)

    Conference Contributions - Other
    University of Canterbury Library

    After consulting key members of the industry (BBR ConTech, Opus International, Fulton Hogan and Beca) it was found that, while the most common failure of RC columns is shear failure, the shear strengthening of RC columns with FRP anchors is fairly well known by engineers, and they are confident in their design. Flexural strengthening of RC columns with FRP anchors is a complex and unknown application and only one example of a research focused on this technique could be found in the existing literature. In addition to verify the applicability of the design equation previously developed, a few aspects not covered in the component tests will be investigated: • The effect of tensile-compression cycles • The effect of dynamic loading • The interaction between adjacent anchors • The behaviour of edge anchors • The effect of overlapped fan components • Behaviour on real case specimen • Effect of different confinement schemes • Effect of different anchor sizes • Strengthening of columns with lap splice failure

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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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  • 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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  • 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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  • Dynamic testing and characterisation of in-service bridges

    Hogan, LS; Wotherspoon, Liam; Beskhyroun, Sherif; Ingham, Jason (2013-04-28)

    Conference item
    The University of Auckland Library

    The following is an overview of a field testing program carried out to investigate the dynamic properties of in-service bridges. Two bridges in the Auckland region, Caitcheon???s Bridge and Glasgow???s Bridge, were subjected to forced vibration testing and a system identification process. The aim of this testing was to determine the in situ dynamic response of each bridge system accounting for both the structural and foundation components. Each bridge was excited in both the transverse and longitudinal direction using an eccentric mass shaker and the response measured with a dense sensor array of up to 160 channels. Testing was performed over two nights at each bridge, with the extensive sensor array and eccentric mass shaker installed and removed each night in order to minimise the impact on normal bridge operations. A description of the test bridges and review of the testing procedures used are first summarised. The characteristics of the overall response of each bridge are then presented with a particular focus on the relative stiffness contributions from the abutments and pier foundations.

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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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  • Strut-and-Tie Model Concepts for Seismic Design and Assessment of Concrete Bridge Joints

    Sritharan, S; Ingham, Jason; Priestley, MJN (2000)

    Conference item
    The University of Auckland Library

    A comprehensive experimental and analytical study on bridge cap beam-to-column concrete joints has been conducted at the University of California at San Diego (UCSD) over the past decade. In this study, the improvement of both detailing and the in-plane seismic performance of bridge joints has been examined by representing the force transfer across the joint using simple strut-and-tie models, which evolved into a rational force transfer method for designing and assessing bridge joints subjected to seismic actions. Starting with joint force conditions and failure modes, this methodology is described in this paper. Some specific strut-and-tie details relevant to seismic behaviour of bridge joints are then discussed, followed by several key joint mechanisms and examples of design models to facilitate application of the proposed method.

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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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  • Performance of unreinforced stone masonry buildings during the 2010/2011 Canterbury earthquake swarm and retrofit techniques for their seismic improvement

    Senaldi, I; Magenes, G; Ingham, Jason (2011-09)

    Journal article
    The University of Auckland Library

    The sequence of earthquakes that has greatly affected Christchurch and Canterbury since September 2010 has again demonstrated the need for seismic retrofit of heritage unreinforced masonry buildings. Commencing in April 2011, the damage to unreinforced stone masonry buildings in Christchurch was assessed and recorded with the primary objective being to document the seismic performance of these structures, recognising that they constitute an important component of New Zealand???s heritage architecture. A damage statistics database was compiled by combining the results of safety evaluation placarding and post-earthquake inspections, and it was determined that the damage observed was consistent with observations previously made on the seismic performance of stone masonry structures in large earthquakes. Details are also given on typical building characteristics and on failure modes observed. Suggestions on appropriate seismic retrofit and remediation techniques are presented, in relation also to strengthening interventions that are typical for similar unreinforced stone masonry structures in Europe.

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  • In-field simulated seismic testing of as-built and retrofitted unreinforced masonry partition walls of the William Weir House in Wellington

    Derakhshan, Hossein; Dizhur, Dmytro; Lumantarna, Ronald; CUTHBERT, J; Griffith, Michael; Ingham, Jason (2010-04)

    Journal article
    The University of Auckland Library

    Unreinforced masonry (URM) partition walls of William Weir House in Wellington were subjected to out-of-plane forces to investigate the as-built wall characteristic behaviour. The lateral load resisting system of the 1932 reinforced concrete building was scheduled to undergo seismic strengthening, and due to the absence of reliable wall out-of-plane assessment data, consulting engineers adopted an experimental proof-testing approach. A team of student researchers from the University of Auckland tested four URM partition walls by subjecting the walls to out-of-plane uniform pressure applied by means of a system of airbags. The testing included two mid-storey and two top-storey URM partitions, which had developed prior minor structural cracks. The full-scale in-situ testing con??? rmed that the precracked partitions had suf??? cient strength to resist the current New Zealand seismic demand, and the experimental programme resulted in substantial ??? nancial bene??? ts for the client as none of the walls were identi??? ed as demolition or strengthening candidates. In addition to the as-builtout-of-plane tests, two tests were conducted on partition walls retro??? tted using nearsurface-mounted (NSM) ??? ber-reinforced polymer (FRP) strips. The results of the as-built and the retro??? tted wall testing are reported, the wall behaviour is evaluated against the current seismic demand and the assessment results are compared with the New Zealand Society for Earthquake Engineering (NZSEE) recommendations.

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  • Diagonal tension strength of vintage unreinforced clay brick masonry wall panels

    Dizhur, Dmytro; Ingham, Jason (2013-06)

    Journal article
    The University of Auckland Library

    An experimental program was implemented where wall panels were obtained from two existing vintage unreinforced clay brick masonry (URM) buildings and subjected to a diagonal compression loading condition in order to induce a diagonal tension failure mode. The principal aims of the experimental program were to establish the diagonal tension strength of the vintage clay brick URM walls present in the two buildings and to establish a benchmark mortar mix suitable for use when manufacturing replica clay brick test assemblages that adequately represent the strength characteristics present in vintage URM buildings. It was concluded that the use of recycled clay bricks acquired from vintage URM buildings and a mortar mix of 1:2:9 (cement:lime:sand) appropriately replicates the material strength characteristics that are present in existing vintage clay brick URM buildings located in New Zealand.

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  • Natural Period and Seismic Idealization of Flexible Timber Diaphragms

    Wilson, Aaron; Quenneville, Pierre; Ingham, Jason (2013-08)

    Journal article
    The University of Auckland Library

    The current equations for diaphragm fundamental period determination and for diaphragm deformation determination published in commonly used seismic assessment documents are firstly reviewed to establish their origin. Using a validated analytical model that captures diaphragm deformation mechanics, three beam idealizations (a fixed-ended flexure beam, a pin-ended flexure beam, and a shear beam) are compared against true diaphragm behavior to determine which idealization is most suitable for the seismic assessment of diaphragm performance. Wherever necessary, recommendations have been made to update and to harmonize the current seismic assessment procedures for timber diaphragms in unreinforced masonry buildings. The presented analysis is specifically focused on straight-sheathed timber diaphragm configurations that are typically found in historic unreinforced masonry buildings.

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  • Time-Dependent Prestress Losses in Historic Clay Brick Masonry Walls Seismically Strengthened Using Unbonded Posttensioning

    Ismail, Najif; Ingham, Jason (2013-06)

    Journal article
    The University of Auckland Library

    Time-dependent prestress losses in historic unreinforced clay brick masonry (URM) walls strengthened using unbonded posttensioning were investigated, with a particular emphasis on masonry shortening resulting from creep and shrinkage. An experimental program was undertaken that involved continuous monitoring of masonry shortening occurring in prestressed URM wallettes over a period of 180 days. The test wallettes were extracted from a real historic URM building and were subjected to varying magnitudes of prestress, representing axial stresses that would be developed at the wall base when strengthened using unbonded posttensioning. A rheological model is proposed for predicting masonry creep shortening, which can subsequently be used to predict posttensioning losses. It was established that a prestress loss of up to 16.4% for normal threaded steel bars and up to 5.4% for sheathed greased seven wire strands can be expected in posttensioned historic URM walls when the tendons are posttensioned to a stress of 0.5?????pu.

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  • Stabilisation of the Cathedral of the Blessed Sacrament following the Canterbury earthquakes

    Lester, JR; Brown, AG; Ingham, Jason (2013-12)

    Journal article
    The University of Auckland Library

    As a result of the 4 September 2010 Darfield earthquake and the more damaging 22 February 2011 Christchurch earthquake, considerable damage occurred to a significant number of buildings in Christchurch. The damage that occurred to the Christchurch Roman Catholic Cathedral of the Blessed Sacrament (commonly known as the Christchurch Basilica) as a result of the Canterbury earthquakes is reported, and the observed failure modes are identified. A previous strengthening intervention is outlined and the estimated capacity of the building is discussed. This strengthening was completed in 2004, and addressed the worst aspects of the building's seismic vulnerability. Urgent work was undertaken post-earthquake to secure parts of the building in order to limit damage and prevent collapse of unstable parts of the building. The approach taken for this securing is outlined, and the performance of the building and the previously installed earthquake strengthening intervention is evaluated.A key consideration throughout the project was the interaction between the structural securing requirements that were driven by the requirement to limit damage and mitigate hazards, and the heritage considerations. Lessons learnt from the strengthening that was carried out, the securing work undertaken, and the approach taken in making the building "safe" are discussed. Some conclusions are drawn with respect to the effectiveness of strengthening similar building types, and the approach taken to secure the building under active seismic conditions.

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