214 results for Ingham, Jason, Conference item

  • 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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  • Seismic performance of a six storey reinforced masonry building during the Christchurch earthquake

    Centeno, J; Ventura, C; Ingham, Jason (2012-09-24)

    Conference item
    The University of Auckland Library

    During the Christchurch earthquake of February 2011, several midrise buildings of Reinforced Concrete Masonry (RCM) construction achieved performance levels in the range of life safety to near collapse levels. These buildings were subjected to seismic demands higher than the building code requirements of the time and higher than the current New Zealand Loadings Standard (NZS-1170.5:2004). Structural damage to these buildings has been documented and is currently being studied to establish lessons to be learned from their performance and how to incorporate these lessons into future RCM design and construction practices. This paper presents a case study of a six story RCM building deemed to have reached the near collapse performance level. The RCM walls on the 2nd floor failed due to toe crushing reducing the building???s lateral resistance in the east-west direction. A nonlinear dynamic analysis on a 3D model was conducted to simulate the development of the governing failure mechanism. Preliminary analysis results show that the damaged walls were initially under large compression forces from gravity loads which caused increase in their lateral strength and reduced their ductility. After toe crushing failure developed, axial instability of the model was prevented by a redistribution of gravity loads.

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  • Vulnerability of New Zealand ports to natural hazards

    Ragued, B; Wotherspoon, Liam; Ingham, Jason (2012-09-24)

    Conference item
    The University of Auckland Library

    Ports are an important part of a country???s infrastructure, both in terms of facilitating trade and aiding recovery immediately following an earthquake. In New Zealand ports facilitate the transfer of up to 99% of all exports and imports by volume and thus are important to the success of the country???s economy. However, these ports are vulnerable to natural hazards which can cause significant damage and impact their operation. This study investigates the current state of New Zealand ports and their vulnerability to natural hazards. Publicly available data on New Zealand ports was supplemented by data sourced from port companies and used to construct a database of the New Zealand ports, including both the wharves??? physical characteristics such as number, size, age, material properties, construction history and economic characteristics such as asset value, cargo volumes and cargo value. The vulnerability of New Zealand ports to seismic, tsunami and volcanic hazards was then examined.

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  • The seismic performance of unreinforced stone masonry buildings during the 2010-2011 Canterbury earthquake sequence

    Senaldi, I; Magenes, G; Ingham, Jason (2012-09-24)

    Conference item
    The University of Auckland Library

    The sequence of earthquakes that has affected Christchurch and Canterbury since September 2010 has caused damage to a great number of buildings of all construction types. Following post-event damage surveys performed between April 2011 and June 2011, the damage suffered by unreinforced stone masonry buildings is reported and different types of observed failures are described. A detailed technical description of the most prevalently observed failure mechanisms is provided, with reference to recognised failure modes for unreinforced masonry structures. The observed performance of existing seismic retrofit interventions is also provided, as an understanding of the seismic response of these interventions is of fundamental importance for assessing the vulnerability of similar strengthening techniques when applied to unreinforced stone masonry structures.

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  • Performance of Unreinforced Masonry Structures in the 2010/2011 Canterbury Earthquake Sequence

    Moon, LM; Griffith, MC; Dizhur, Dmytro; Ingham, Jason (2012-09-24)

    Conference item
    The University of Auckland Library

    Following the magnitude 6.3 aftershock in Christchurch, New Zealand, on 22 February 2011, a number of researchers were sent to Christchurch as part of the New Zealand Natural Hazard Research Platform funded ???Project Masonry??? Recovery Project. Their goal was to document and interpret the damage to the masonry buildings and churches in the region. Approximately 650 unreinforced and retrofitted clay brick masonry buildings in the Christchurch area were surveyed for commonly occurring failure patterns and collapse mechanisms. The entire building stock of Christchurch, and in particular the unreinforced masonry building stock, is similar to that in the rest of New Zealand, Australia, and abroad, so the observations made here are relevant for the entire world.

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  • Review of transect of Christchurch CBD following 22 February 2011 earthquake

    Moon, LM; Griffith, MC; Ingham, Jason; Biggs, D (2012-09-24)

    Conference item
    The University of Auckland Library

    Two days after the 22 February 2011 M6.3 earthquake in Christchurch, New Zealand, three of the authors conducted a transect of the central city, with the goal of deriving an estimate of building damage levels. Although smaller in magnitude than the M7.1 4 September 2010 Darfield earthquake, the ground accelerations, ground deformation and damage levels in Christchurch central city were more severe in February 2011, and the central city was closed down to the general public. Written and photographic notes of 295 buildings were taken, including construction type, damage level, and whether the building would likely need to be demolished. The results of the transect compared favourably to Civil Defence rapid assessments made over the following month. Now, more than one year and two major aftershocks after the February 2011 earthquake these initial estimates are compared to the current demolition status to provide an updated understanding of the state of central Christchurch.

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  • Seismic Performance of Masonry Buildings in the Christchurch Earthquakes 2010-2011: A Progress Report

    Moon, LM; Dizhur, D; Ingham, Jason; Griffith, MC (2012-12-07)

    Conference item
    The University of Auckland Library

    Following the Christchurch earthquake of 22 February 2011 a number of researchers were sent to Christchurch, New Zealand to document the damage to masonry buildings as part of ???Project Masonry???. Coordinated by the Universities of Auckland and Adelaide, researchers came from Australia, New Zealand, Canada, Italy, Portugal and the US. The types of masonry investigated were unreinforced clay brick masonry, unreinforced stone masonry, reinforced concrete masonry, residential masonry veneer and churches; masonry infill was not part of this study. This paper focuses on the progress of the unreinforced masonry (URM) component of Project Masonry. To date the research team has completed raw data collection on over 600 URM buildings in the Christchurch area. The results from this study will be extremely relevant to Australian cities since URM buildings in New Zealand are similar to those in Australia.

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  • Using simplified indices to forecast the seismic vulnerability of New Zealand unreinforced masonry churches

    Ingham, Jason; Lourenco, PB; Leite, J; Castelino, S; Colaco, E (2012-12-07)

    Conference item
    The University of Auckland Library

    Unreinforced masonry churches are particularly vulnerable to earthquakes because they are often deteriorated and damaged, they were built with comparatively low strength materials, they are heavy, and the connections between the various structural components are often insufficient to resist loads generated during earthquakes. A simplified method for seismic assessment of large span masonry churches is presented and data from 44 churches located in Italy, Portugal and Spain are used to provide lower bound limits for different simplified geometrical indexes. Subsequently, the proposed thresholds are validated with data from the 2010-2011 Canterbury earthquakes, including 48 clay brick and stone unreinforced masonry churches. Finally, data collected for 40 unreinforced masonry churches in Wellington and Dunedin are used to identify churches in these cities requiring priority detailed seismic evaluation.

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  • Implications of the 2010 Darfield (Christchurch, NZ) earthquake for Australia ??? are we ready?

    Griffith, MC; Ingham, Jason; Moon, L (2010)

    Conference item
    The University of Auckland Library

    The 2010 Darfield earthquake is the largest earthquake on record to have occurred within 40 km of a major city and not cause any fatalities. In this paper the authors have reflected on their experiences in Christchurch following the earthquake with a view to what worked, what didn???t, and what lessons can be learned from this for the benefit of Australian earthquake preparedness. Owing to the fact that most of the observed building damage occurred in Unreinforced Masonry (URM) construction, this paper focuses in particular on the authors??? experience conducting rapid building damage assessment during the first 72 hours following the earthquake and more detailed examination of the performance of unreinforced masonry buildings with and without seismic retrofit interventions.

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