213 results for Ingham, Jason, Conference item

  • 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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  • Assessing the validity of rocking in URM perforated shear walls

    Knox, Charlotte; Ma, Tsun Ming Quincy; Ingham, Jason (2010)

    Conference item
    The University of Auckland Library

    The validity of implementing a ???rocking wall retrofit??? for New Zealand???s earthquake prone unreinforced masonry buildings was assessed. The parameters governing rocking response are detailed, and the identification of rocking-sympathetic characteristics in representative New Zealand unreinforced masonry building typologies are highlighted. A series of experimental tests were conducted in order to identify variables that had potential to alter the rocking response of piers subjected to seismic loading. The influence of boundary conditions on the failure mechanism of unreinforced masonry piers is discussed in relation to the design of the full scale testing rig. Results from testing of two full scale unreinforced masonry sub-structures consisting of two piers coupled by a deep spandrel are reported. The tests access the influence of aspect ratio and vertical precompression levels on the forcedisplacement and pier-spandrel rotational behaviour. Crack patterns evidenced in a series of plaster formed scale models is compared to those developed during full scale pseudo-static cyclic tests on unreinforced masonry shear walls of the same geometry.

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  • In-plane design loads for seismic assessment and retrofit of walls in unreinforced masonry buildings

    Ingham, Jason; Knox, CL; Wilson, AW; Elwood, Kenneth (2011-05-26)

    Conference item
    The University of Auckland Library

    It is well established and routinely observed that unreinforced masonry buildings perform poorly in large earthquakes. This knowledge directly points to the need for a detailed procedure for the seismic assessment and retrofit of unreinforced masonry buildings. Pivotal to the entire assess-ment and retrofit process is the accurate treatment of the dynamic characteristics of flexible timber floor diaphragms, and the development of a straightforward and accurate method for determining the in-plane seismic loads on walls when accounting for both excitation due to self weight, and seismic demand transmitted via wall-diaphragm connections. Pertinent details of the M7.1 2010 Darfield (Canterbury) earthquake are presented, followed by a re-view of results from a large scale experimental program that investigated the strength and stiffness characteristics of timber diaphragms. Next, details are provided of a procedure for determining dia-phragm dynamic characteristics recognizing that diaphragm deformations are primarily associated with shear rather than flexure. Finally, details are summarised of a methodology now adopted in New Zealand for determining the in-plane seismic demand on unreinforced masonry walls.

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  • Management of flushing of chipseal pavements using multiple assessment techniques

    Kodippily, Sachi; Henning, Theunis; Ingham, Jason; Holleran, Glynn (2014-01-01)

    Conference item
    The University of Auckland Library

    Flushing is a defect which has a damaging effect on the functional performance of chipseal pavements. This study aimed to develop techniques to effectively identify and assess flushed pavements. Samples from flushed chipseal pavements were subjected to wheeltracking, and specimens from wheeltracked samples were analysed using image analysis techniques to calculate the volume of air voids. Data analysis was performed on pavement condition data to develop a model to predict the initiation and progression of flushing. A direct relationship was found between air void volume reduction and flushing. The data analysis revealed that the factors that contributed most to flushing were surface thickness, surface age, rut depth and grade of aggregates. The developed flushing initiation model had an accuracy of 74% and the flushing progression model was robust at predicting the quantity of flushing. The study resulted in identifying effective methods for assessing flushing on chipseal pavements.

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  • Assessing the rocking response of unreinforced masonry frames in historical New Zealand structures

    Knox, CL; Ma, Tsun Ming Quincy; Ingham, Jason (2009)

    Conference item
    The University of Auckland Library

    The signing of the Treaty of Waitangi in 1840 indentified New Zealand as a British colony. The subsequent influx of British migrants to New Zealand saw the introduction of colonial settlements modelled on the structure of British society. In the late 1800's the comparative absence of knowledge, with respect to the performance of unreinforced masonry (URM) during earthquakes, left unreinforced masonry as the unsurpassed choice for construction of New Zealand's commercial and monumental structures in the rapidly expanding urban centres nationwide. During the 1931 Hawke's Bay Earthquake URM construction was repeatedly proven to perform unsatisfactorily, resulting in a rapid decline in popularity and subsequent prohibition of use in 1965. Its prevalence throughout New Zealand's historic building stock dating between 1880 and the 1935, has lead to the New Zealand government issuing an act effectively requiring all URM buildings to be assessed and seismically retrofitted accordingly.Accurate analysis of the structural response of unreinforced masonry buildings to earthquake loading is essential to the design of efficient and effective seismic retrofit interventions. Five typical masonry frames which are representative of the over 3500 URM buildings found around New Zealand are reported. These five frames include one, two, three and six storey buildings as well as row and stand alone type buildings. International research indicates that the geometric properties of the frame significantly control the type of energy dissipation method adopted by the structure.

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  • Effects of chipseal pavement material interactions on flushing

    Kodippily, Sachi; Henning, Theunis; Ingham, Jason (2012-08)

    Conference item
    The University of Auckland Library

    Chipseal surfacings are a cost-effective and widely used option for roads having low traffic volumes. Frequent resurfacing is a common maintenance option used on chipseal pavements to maintain skid resistance and prevent moisture damage. The increase in surface thickness, resulting from a build-up of surfacing layers, and excess binder quantities often lead to flushing or bleeding on the pavement surface. Once flushed, maintenance of these surfaces becomes problematic and often full pavement rehabilitation is required. Flushing develops due to the micromechanical interactions between materials within a chipseal layer. In particular, the presence of air voids within a chipseal structure plays a vital role in the extent to which bitumen movement can happen. Thus, a thorough understanding of the mechanistic nature of flushing is essential for better management of chipseal pavements. The reported study was carried out to examine the micromechanical interactions between chipseal layer materials and their relationship to flushing using image analysis techniques. In particular, the effectiveness of using image analysis techniques to analyse the changes in air voids that occur within a chipseal layer during loading were investigated. This study was based on laboratory testing of chipseal pavement cores from in-service pavements from Auckland and Waikato regions of New Zealand. The cores, of 200 mm diameter and thicknesses ranging from 32.4 mm to 44.5 mm, were subjected to lateral cyclic loading and changes to the volume of air voids that had occurred were recorded. Samples from loaded cores were then scanned using a Computed Tomography (CT) scanner to examine the effects of loading on the distribution of air voids. The results from the study showed that image analysis is an effective tool to analyse air voids within a chipseal layer.

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  • Experimental Study of Unreinforced Masonry Pier Sub-Structures

    Knox, Charlotte; Russell, Alistair; Ingham, Jason (2010)

    Conference item
    The University of Auckland Library

    Accurate assessment of the structural response of unreinforced masonry buildings when subjected to earthquake loading is essential for the design of efficient and effective seismic retrofit interventions. This study focused on determining the in-plane seismic performance of unreinforced masonry perforated shear walls in order to implement controlled rocking response as a hybrid retrofit solution. The experimental programme and the findings from a series of pseudo-static push-over tests performed on coupled unreinforced masonry pier sub-structures is presented. These sub-structures consisted of two piers with varying aspect ratio and absolute size and were subjected to different levels of vertical overburden. The walls were constructed in the common American bond formation using solid clay bricks and a 1:2:9 composition lime mortar, consistent with historical New Zealand unreinforced masonry buildings. The specimen geometries were chosen to not only replicate typical New Zealand unreinforced masonry perforated shear wall geometries but to also provide data on the three possible failure mechanisms ??? diagonal shear failure, sliding shear failure and rocking flexural response.When subjected to horizontal load the piers in both sub-structures exhibited a rocking response, with no diagonal shear cracking visible. The damage was concentrated in the spandrel section that spanned across the opening and this was attributed to both flexure and shear forces within the spandrel.

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  • Remembering Professors Paulay, Park and Priestley

    Ingham, Jason; Bull, D; twigden, K (2015-10-08)

    Conference item
    The University of Auckland Library

    Professors Tom Paulay, Bob Park and Nigel Priestley each made a massive contribution to structural seismic concrete design both in New Zealand and internationally, receiving numerous international awards and commendations for their research. Alas, all have now passed away and in this article the authors seek to honour their memory and their contribution to the New Zealand concrete industry. The reported information derives from archive material and memories from colleagues and former students, to not only explain the technical contributions of these three great men, but also the mentoring and training that they provided to a generation of civil engineers.

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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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  • 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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  • 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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  • 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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  • 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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  • 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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  • 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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  • What ductility value should be used when assessing unreinforced masonry buildings

    Allen, C; Masia, M; Derakhshan, H; Griffith, MC; Dizhur, Dmytro; Ingham, Jason (2013-04-26)

    Conference item
    The University of Auckland Library

    There has been much discussion regarding the appropriate values of structural ductility factor, structural performance factor, and equivalent viscous damping coefficient to be used in the assessment of unreinforced masonry (URM) buildings in New Zealand and Australia. The New Zealand Society for Earthquake Engineering 2006 guidelines proposes a ductility factor of 1.0 to be used along with a damping coefficient ratio of 15%. A draft guideline recently developed by researchers from the University of Auckland suggests that a ductility factor of 2.0 and damping ratio of 5% is more suitable. Elsewhere in the world, other researchers have made recommendations regarding these topics. Furthermore, the Canterbury Earthquakes Royal Commission has recently recommended this topic receive further attention. Different alternatives are evaluated by conducting Nonlinear Static (pushover) analyses for a representative URM structure. A comparison is made to previous experimentally and analytically derived equivalents. Following this research, a recommendation is made regarding values which should be used in future design. Results of a simplified plane stress analysis for this building are also presented and compared to the results obtained from the pushover analyses.

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  • Provisional seismic assessment and improvement of Napier's Art Deco buildings

    Walsh, Kevin; Ingham, Jason (2013-04-26)

    Conference item
    The University of Auckland Library

    Following the 1931 Hawke???s Bay earthquake, buildings in Napier and surrounding areas were rebuilt in a comparatively homogenous structural and architectural style comprising the region???s famous Art Deco stock. These ???interwar buildings??? are most often composed of reinforced concrete frames and, while detailed in a fairly ductile fashion for the time, often register as earthquake-prone in preliminary seismic assessments, causing concern to owners, tenants, city officials, and all of those who value the heritage and future use of these iconic structures. The study reported here will address aspects of the seismic hazard, assessment, and potential retrofit solutions for Napier???s Art Deco buildings. The study concluded with provisional recommendations developed in collaboration with the Napier Art Deco Trust and other interested parties regarding a pathway to alleviate the hazard posed by Napier???s Art Deco buildings.

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