324 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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  • Unbonded Tendon Stresses in Post-Tensioned Concrete Walls at Nominal Flexural Strength

    Henry, Richard; SRITHARAN, S; Ingham, Jason (2012)

    Journal article
    The University of Auckland Library

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  • A Seismic Retrofit Cost Database for Buildings Having a Framed Structure

    Jafarzadeh, R; Ingham, Jason; Wilkinson, Suzanne (2014)

    Journal article
    The University of Auckland Library

    A comprehensive database for the specific challenge of cost prediction when undertaking seismic retrofitting of existing buildings is presented. A rigorous data collection effort performed in Iran resulted in the generation of a database of 158 data points, each pertaining to a public school building with a framed structure. The generated database includes the information on the seismic retrofit cost values reflected in construction tender documents, together with the information on 14 variables envisaged to have a degree of influence on this cost. This information for a given building was carefully elicited from the final enacted documents developed through the seismic retrofit study of that particular school. Construction costs include structural costs and the costs of architecture and finishes. The database could be of value to those attempting to determine key variables that influence retrofit cost, or to those comparing retrofit practices and costs in different areas of the world.

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  • Empirical Damage Relationships and Benefit-Cost Analysis for Seismic Retrofit of URM Buildings

    Paxton, B; Elwood, Kenneth; Ingham, Jason (2017-08)

    Journal article
    The University of Auckland Library

    Benefit-cost analyses for seismic retrofit of unreinforced masonry (URM) buildings in downtown Victoria, British Columbia, Canada were undertaken, considering the seismic hazard, building value, occupant/pedestrian exposure, a variety of strengthening measures, and local construction costs. The analyses are underpinned by building motion-damage relationships developed based on observed damage in past earthquakes in California and New Zealand. The considered upgrading measures ranged from parapet bracing to comprehensive seismic upgrades consistent with local practices. Parapet bracing and other partial retrofits were shown to have favorable benefit-cost ratios and thus be strong candidate measures for risk mitigation programs. Full upgrades were shown to have less favorable benefit-cost ratios. While applied to Victoria, the generality of the methodology and the use of observed damage data from California and New Zealand make the findings of this study particularly relevant for similar locations throughout the Pacific Northwest and abroad.

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  • Unreinforced stone masonry buildings in New Zealand: Inventory and material characterisation

    Giaretton, M; Dizhur, Dmytro; da Porto, F; Ingham, Jason (2014-07-07)

    Conference item
    The University of Auckland Library

    The high seismic vulnerability of unreinforced stone masonry (URM) buildings was once again demonstrated in the recent Canterbury earthquakes (2010-2011). The shortage of knowledge about New Zealand historic URM buildings, and about techniques for their conservation, led to numerous losses, both in terms of lives and architectural heritage. Almost all URM buildings in New Zealand were constructed between 1860 and 1910, typically in regions where natural stone (in particular basalt, schist and limestone) was sourced from local quarries, fields and rivers. There are estimated to be approximately 688 URM buildings in New Zealand, with most being a potential earthquake risk. As a first step, an inventory of the URM buildings of New Zealand was compiled, listing location, construction details and architectural configuration. A further development was the inspection of representative case study buildings, where architectural characteristics and extracted material samples were obtained. Compressive tests and petrographical analyses were undertaken on natural stone specimens, while compressive strength and mineralogical composition were determined for mortar samples. The aim of the study reported herein was to acquire a thorough understanding of the mechanical and physical properties of these URM buildings in order to assess seismic vulnerability factors and potential seismic improvement solutions.

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  • Unbonded Prestressed Panel Tendon Stresses at In-Plane Nominal Flexural Strength

    Brooke, Nicholas; Wight, Gavin; Russell, Alistair; Ingham, Jason (2007)

    Conference item
    The University of Auckland Library

    A series of in-plane tests on post-tensioned concrete wall panels with unbonded tendons are described. These tests were used to verify that tendon stresses at nominal flexural strength can be accurately predicted for concrete walls using an equation previously developed for post-tensioned concrete masonry walls. Testing showed that the equation gives more accurate prediction of tendon stress than current design methods used in New Zealand. A secondary objective was to examine the accuracy of ???true??? predictions of wall performance obtained by finite element analysis. Predictions of wall forcedisplacement response, tendon stress increase and concrete strain generally matched experimental data with acceptable accuracy. The experimental response of some walls was significantly influenced by the existence of a bedding layer with low stiffness, which could not be accurately modelled.

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  • Monotonic testing of unreinforced and GFRP-retrofitted masonry walls prone to shear failure in an earthquake

    Mahmood, Hamid; Russell, Alistair; Ingham, Jason (2008)

    Conference item
    The University of Auckland Library

    A research programme has been initiated in New Zealand to address concerns regarding the seismic performance of New Zealand???s unreinforced masonry (URM) building stock. As a component of this programme, monotonic in-plane shear (diagonal compression) tests were conducted on URM wallettes to simulate the commonly observed diagonal shear failure of in-plane walls in an earthquake. In total, four wallettes were tested, three of which were retrofitted with various configurations of GFRP strips. The unretrofitted wallette failed in a brittle manner. The retrofitted wallettes exhibited a more ductile behaviour. Significant increases in wallette strength and pseudo-ductility were achieved by the application of GFRP.

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  • Proposed design guidelines for shear retrofit of in-plane loaded clay brick wall using externally-bonded FRP

    Mahmood, H; Ingham, Jason (2011)

    Conference item
    The University of Auckland Library

    A comparison of existing design guidelines for retrofit using externally-bonded fibre reinforced polymer (FRP) materials of in-plane loaded unreinforced masonry walls likely to fail in a shear mode was performed. The design guidelines were evaluated by comparing predicted values of FRP shear strength contribution with the experimental results. The ACI model was determined to be the most accurate and consistent model. Design expressions for shear retrofit using vertically-oriented FRP were proposed.

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  • Diagonal shear testing of unreinforced brick-masonry wallettes retrofitted with CFRP plates

    Mahmood, Hamid; Ingham, Jason (2009)

    Conference item
    The University of Auckland Library

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  • Strut-and-Tie Modelling of Fibre Reinforced Precast Concrete Beam-Column Joints

    Brooke, Nicholas; Ingham, Jason; Wight, Gavin (2007)

    Conference item
    The University of Auckland Library

    In this paper, topics related to the use of fibre reinforced cementitious composites (FRCCs) in beam-column joint cores are discussed. A review is presented of the ways in which FRCCs are classified, from which it is concluded that development of reliable methods for assessing the tensile properties of FRCCs is essential. Key results are presented from the testing of two beam-column joint sub-assemblies with FRCC joint cores, and a qualitative assessment is made of the mechanisms by which forces were transferred through the joint core. The paper is concluded with a discussion of the expected performance of further beam-column joints currently being tested.

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  • Out-of-plane seismic performance of unreinforced masonry walls retrofitted using post-tensioning

    Ismail, N; Schultz, AE; Ingham, Jason (2012)

    Conference item
    The University of Auckland Library

    The development of equations for a post-tensioning seismic retrofit design of URM walls is discussed and a summary of out-of-plane flexural testing is reported. A total of five (05) full scale unreinforced masonry (URM) walls, of which one was tested as-built and four were seismically retrofitted using post-tensioning, were structurally tested using an out-of-plane air bag rig. The out-of-plane loaded test walls had two different wall configurations that were representative of prevalent seismically deficient URM walls and were constructed using salvaged clay bricks and an ASTM type O mortar. Varying levels of post-tensioning were applied to the test walls using a single mechanically restrained sheathed and greased strand, inserted into a cavity at the centre of each test wall. Several aspects pertaining to the seismic behaviour of post-tensioned URM walls were investigated, including damage patterns, forcedisplacement behaviour, tendon stress variation, hysteretic energy dissipation, toughness, and initial stiffness. Finally, measured response was compared to calculated values and the proposed design equations were validated.

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  • Vibration testing of an in situ bridge pier to determine soil-structure interaction effects

    Hogan, Lucas; Wotherspoon, Liam; Beskhyroun, Sherif; Ingham, Jason (2012-09-24)

    Conference item
    The University of Auckland Library

    The lateral dynamic response characteristics of a single span from the decommissioned Puhinui Stream Bridge in Manukau, New Zealand were determined through a series of forced vibration tests performed along the longitudinal axis of the bridge using an eccentric mass shaker. Following forced vibration testing, the dynamic characteristics of a three column pier group from the span were determined using snapback testing. Responses of the bridge span and pier group measured during the vibration testing were used to construct finite element models accounting for soil-structure interaction using a Winkler spring idealisation of the soil. Because of the simplified nature of the pier group, it was modelled first, and used to perform sensitivity analyses to obtain realistic bounds for soil and material properties based upon CPT data and concrete specifications. The pier group model will be extended to capture the response measured by the forced vibration testing of the bridge span but is not discussed here.

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  • The Performance of Ductile R/C Frames under Seismic Loading

    Fenwick, Richard; Ingham, Jason; Wuu, PJ (1996)

    Conference item
    The University of Auckland Library

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  • Assessing the Bolted Connection Strength of New Zealand Hardwood

    Abdul Karim, Abdul Razak; Quenneville, Pierre; M Sa'Don, N; Ingham, Jason (2010)

    Conference item
    The University of Auckland Library

    From published literature, it was found that through-bolt connections were typically applied as a retrofit technique to most New Zealand unreinforced masonry (URM) buildings following the 1931 Hawke???s Bay earthquake. As connection failure by tearing out part of the diaphragm joist was observed in past earthquakes due to lateral earthquake loading, the strength of the bolted connection in existing indigenous New Zealand timber joists needs to be assessed. The main objectives of this study were to evaluate the strength and to identify the possible failure modes of bolted connections in New Zealand hardwood. Bolted connection tests loaded parallel-to-grain were performed using recycled native New Zealand Matai and Rimu hardwoods because the timber diaphragms in URM buildings are typically constructed using such wood species. From the experimental study, it was observed that the timber bolted connection can fail in either ductile or brittle modes. The test results obtained were compared with the European Yield Model (EYM), the New Zealand timber code (NZS 3603:1993), and a proposed set of equations (Quenneville 2009) in order to evaluate the applicability of those equations in predicting bolted connection strength for New Zealand hardwood. It was found that the EYM equations provide better predictions than the NZS 3603:1993 when compared to the actual capacity. However, the EYM predictions are only good in estimating the strength of timber bolted connections that fail under ductile mode. For the connections that fail exhibiting the brittle mode, the proposed row shear equation by Quenneville was found to give better strength estimation.

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  • In-Plane Sesimic Response of Joints in Multi-Column Bents of Concrete Bridges

    Ingham, Jason; Sritharan, S; Priestley, MJN; Seible, F (1996)

    Conference item
    The University of Auckland Library

    Experimental investigations were conducted on the in-plane seismic response of both exterior (knee) and interior (tee) large-scale beam-column bridge joint sub-assemblies. These investigations were supported by parallel analytical studies based on rational joint force transfer models. Utilising design strategies developed from the preliminary investigations, two further units incorporating new design techniques were tested. The application of headed reinforcement in the first unit and cap beam prestressing in the second unit greatly reduced congestion of joint reinforcement, when compared with the equivalent joints designed using conventional methods. Excellent response was obtained for both new designs, confirming the validity of the rational design procedure.

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  • Christchurch Cathedral of the Blessed Sacrament: Lessons Learnt on the Stabilisation of a Significant Heritage Building

    Lester, J; Brown, A; Ingham, Jason (2012-04-13)

    Conference item
    The University of Auckland Library

    The Catholic Cathedral of the Blessed Sacrament is a category 1 listed heritage building constructed largely of unreinforced stone masonry, and was significantly damaged in the recent Canterbury earthquakes. The building experienced ground shaking in excess of its capacity leading to block failures and partial collapse of parts of the building, which left the building standing but still posing a significant hazard. In this paper we discuss the approach to securing the building, and the interaction of the structural, heritage and safety demands involved in a dynamic seismic risk environment. We briefly cover the types of failures observed and the behaviour of the structure, and investigate the performance of both strengthened and un-strengthened parts of the building. Seismic strengthening options are investigated at a conceptual level. We draw conclusions as to how the building performed in the earthquakes, comment on the effectiveness of the strengthening and securing work and discuss the potential seismic strengthening methods.

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  • Performance of masonry buildings during the 2010 Darfield (New Zealand) earthquake

    Ismail, N; Griffith, M; Ingham, Jason (2011-06-05)

    Conference item
    The University of Auckland Library

    The M7.1 Darfield earthquake shook the town of Christchurch (New Zealand) in the early morning on Saturday 4th September 2010 and caused damage to a number of heritage unreinforced masonry buildings. No fatalities were reported directly linked to the earthquake, but the damage to important heritage buildings was the most extensive to have occurred since the 1931 Hawke???s Bay earthquake. In general, the nature of damage was consistent with observations previously made on the seismic performance of unreinforced masonry buildings in large earthquakes, with aspects such as toppled chimneys and parapets, failure of gables and poorly secured face-loaded walls, and in-plane damage to masonry frames all being extensively documented. This report on the performance of the unreinforced masonry buildings in the 2010 Darfield earthquake provides details on typical building characteristics, a review of damage statistics obtained by interrogating the building assessment database that was compiled in association with post-earthquake building inspections, and a review of the characteristic failure modes that were observed.

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  • Studies on the material properties of the Aurora Tavern, Auckland

    Lumantarna, R; Dizhur, D; Liu, P; Ingham, Jason (2011-04-14)

    Conference item
    The University of Auckland Library

    The Aurora Tavern was one example of many heritage unreinforced masonry (URM) buildings in New Zealand, and therefore like other existing URM buildings, this hotel was vulnerable to damage should a moderate magnitude earthquake occur. Refurbishment and strengthening work was being implemented on the building, during which in-situ testing was performed to investigate the building???s material properties. The URM materials in the Aurora Tavern were generally in poor condition, and water ingress was observed at various locations in the building. In-situ deformability tests and bed joint shear tests were conducted on-site to determine the masonry stiffness and the mortar bed joint shear strength respectively. In addition, individual brick units and irregular mortar samples were extracted for compression testing in the laboratory. Laboratory mortar compression tests and in-situ deformability tests showed that the mortar compressive strength and masonry Modulus of Elasticity were low. However, the brick compressive and mortar bed joint shear strengths were comparable to those of other buildings that were previously investigated by the research team.

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  • Report on the ???Project Masonry??? recovery project

    Dizhur, D; Ingham, Jason (2012-11-02)

    Conference item
    The University of Auckland Library

    As part of the ???Project Masonry??? Recovery Project funded by the New Zealand Natural Hazards Research Platform, commencing in March 2011, an international team of researchers was deployed to document and interpret the observed earthquake damage to masonry buildings and to churches as a result of the 22nd February 2011 Christchurch earthquake. The study focused on investigating commonly encountered failure patterns and collapse mechanisms. A brief summary of activities undertaken is presented, detailing the observations that were made on the performance of and the deficiencies that contributed to the damage to approximately 650 inspected unreinforced clay brick masonry (URM) buildings, to 90 unreinforced stone masonry buildings, to 342 reinforced concrete masonry (RCM) buildings, to 112 churches in the Canterbury region, and to just under 1100 residential dwellings having external masonry veneer cladding. Also, details are provided of retrofit techniques that were implemented within relevant Christchurch URM buildings prior to the 22nd February earthquake. In addition to presenting a summary of Project Masonry, the broader research activity at the University of Auckland pertaining to the seismic assessment and improvement of unreinforced masonry buildings is outlined. The purpose of this outline is to provide an overview and bibliography of published literature and to communicate on-going research activity that has not yet been reported in a complete form.

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