Opus International Consultants

Melbourne, Australia

Opus International Consultants

Melbourne, Australia
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Barounis N.,Opus International Consultants | McMahon P.,University of Bolton
Geotechnical Engineering for Infrastructure and Development - Proceedings of the XVI European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2015 | Year: 2015

A method for the rapid estimation of the subgrade reaction coefficient k for sands was introduced in 2013 (Barounis et al.) from CPT data. In this paper the method is applied for a building site in Christchurch, New Zealand that suffered structural damage from the recent Canterbury earthquakes. The method is relying on qc measured and a value for k from CPT (Kcpt) is obtained. This value is further corrected for size effects and after the use of a back calculated factor of safety, the value corresponding for a given foundation shape and depth is estimated. The results correlate sufficiently with published values for foundations on loose to medium dense sands. © The authors and ICE Publishing: All rights reserved, 2015.

Taylor P.,Opus International Consultants | Romaniw N.,Tower Surveys Ltd. | Nicholls K.H.,Opus International Consultants
Geotechnical Engineering for Infrastructure and Development - Proceedings of the XVI European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2015 | Year: 2015

Due to the age, scale and detail of many mine abandonment plans their accuracy can often be of concern particularly when development is proposed above or close to the historic workings. This can often result in both expensive and time consuming investigations to prove the accuracy or not of these plans. During recent investigation works for a proposed residential development above an area of historic Bath Stone workings the opportunity to access a section of historic workings arose. This allowed both a visual inspection of the workings, as well as the opportunity to undertake a detailed 3Dimensional laser scan which could be transposed onto both current and proposed surface features. The output of the laser scan showed the workings in greater clarity and accuracy than that afforded by the traditional visual inspection, and allowed an assessment of the impact of the workings on the proposed development to be made. This paper describes the work undertaken on site in detail, and presents the detailed survey imagery. © The authors and ICE Publishing: All rights reserved, 2015.

Chalmers G.,Opus International Consultants | McLennan N.,Lyttelton Port of Christchurch | Barsanti L.,Opus International Consultants
Ports 2013: Success Through Diversification - Proceedings of the 13th Triennial International Conference | Year: 2013

Lyttelton Port of Christchurch (LPC) is situated on the east coast of the South Island of New Zealand, which lies south east of Australia. Neither of the two major reclamations at LPC experienced significant liquefaction during the four significant earthquakes of 2010/2011, which caused accelerations between 1.2 and 5 times previous design code levels. The epicentre of the most damaging earthquake was some 4 km distant and only 5 km deep. Significant damage to wharves, sea walls, and pavements occurred. Most key wharf assets will require complete reconstruction. This paper considers the asset management planning undertaken prior to the events including: fragility modelling, the damage sustained, and the resulting outages that occurred. It also discusses how the prior planning and fragility modelling assisted the work during the emergency and recovery periods. The effect of multiple heavily damaging earthquakes in close proximity to the port is also discussed. © 2013 American Society of Civil Engineers.

Wright C.,Opus International Consultants | Thorpe D.,University of Southern Queensland
Proceedings of the 31st Annual Association of Researchers in Construction Management Conference, ARCOM 2015 | Year: 2015

The use of advanced and green materials by the construction industry can significantly improve sustainability by reducing demand on scarce resources, reducing greenhouse gas emissions, improving safety, facilitating resilience of structures and encouraging the use of modern construction practices. Examples of such material include laminated veneer lumber, glulam, rammed earth, high strength concrete, lightweight concrete and adobe brick. To evaluate the use of such materials, an exploratory survey was conducted on-line in Australia and New Zealand into their use by small and medium enterprises (SMEs) that were undertaking either design or construction. The purpose of this survey was to better understand the use of such materials by the selected firms, understand why they were used or not used, and assess their likelihood of use in the future. Thirty firms responded to the survey. Each firm was asked to respond in detail to the use of five advanced and green materials, selected from a total number of sixteen. The extent to which these materials were used varied by individual firms and their role in the industry. It was found that there were seven leading issues (or factors) with respect to the use of such materials. The range of factors tended to depend on whether or not the firm had used the selected material. Experience appeared to be the leading issue restricting the uptake of individual materials. Other factors included cost of material and the availability of standards or codes of practice. While it is recognised that further work is required to validate the results of this research and extend it beyond Australia and New Zealand, this survey has given good insight into the use of these materials by SME firms in the construction industry.

Davey R.A.,Opus International Consultants
Bulletin of the New Zealand Society for Earthquake Engineering | Year: 2010

The M w 7.1 earthquake that struck 40 km west of Christchurch on 4 September 2010 provided a good test of the robustness of the water storage and distribution system of one of our major cities to provide a secure supply of water. In this paper we present damage data from inspections of 54 reservoirs that were undertaken on behalf of Christchurch City Council and other owners. These included concrete, steel and timber tanks, five of which collapsed and four severely damaged.

MacRae G.A.,University of Canterbury | Clifton G.C.,University of Auckland | Mackinven H.,Opus International Consultants | Mago N.,New Zealand Heavy Engineering Research Association | And 2 more authors.
Bulletin of the New Zealand Society for Earthquake Engineering | Year: 2010

A new friction moment joint for steel framed structures is described. It has a similar cost to conventional construction and is designed such that there is negligible damage to the frame or slabs. Experimental testing shows that steel, brass or aluminium shims can provide satisfactory friction resistance and that there is almost no damage to the frame during design level displacements. A method for establishing the dependable friction force is developed considering construction tolerances and bolt moment-axial-force-shear interaction. A design methodology for the joint and a design example are provided.

Saleh M.,University of Canterbury | Cullum M.,Opus International Consultants
7th International Conference on Maintenance and Rehabilitation of Pavements and Technological Control, MAIREPAV 2012 | Year: 2012

The analysis of stresses, strains and deflections in rigid pavement is an important step in the mechanistic pavement design of new pavements and rehabilitation design of existing pavements. However the closed form solutions have a limited usefulness due to their very simple loading cases and pavement structure. In order to consider actual loading cases and realistic pavement structures a finite element analysis is needed. To perform finite element analysis special expertise, suitable software and a great amount of time is needed. In this research, the outputs of finite elements for multiple axle loads, pavement configurations and material properties was used to train an artificial neural network to predict stresses and deflection in rigid pavement with great accuracy. The fully trained network can be used to predict unseen data with a mean squared error of 0.002. More research can be done in the future in order to make the use of artificial neural network more attractive to practitioners.

Herrington P.R.,Opus International Consultants
Fuel | Year: 2012

A numerical model to predict the diffusion and reaction of oxygen in petroleum bitumen films was developed, and compared to experimental data obtained by oxidation of bitumen films at 50°C and atmospheric pressure in the absence of light. Experimental viscosity-depth profiles were obtained by microtoming 3-4 mm thick, oxidized, bitumen films at approximately 100 μm intervals. Model parameters for the diffusion-oxidation process were obtained by correlating oxygen uptake of bitumen solutions to changes in carbonyl infrared spectral absorption and viscosity. The model developed, predicted the average viscosity in bitumen films after oxidation at 50°C for up to 126 days (approximately equivalent to 2 years in the field) with an accuracy of ±20%. © 2011 Elsevier Ltd. All rights reserved.

White S.,Opus International Consultants | Palermo A.,University of Canterbury
Journal of Bridge Engineering | Year: 2016

Accelerated bridge construction (ABC) is gaining popularity because it offers a number of advantages over conventional methods of construction. Prefabrication of bridge components for rapid on-site assembly is a highly effective ABC approach. Bridge substructures are traditionally cast in place with columns that form plastic hinges during earthquake events. Recent studies have explored new precast columnfooting connections that either emulate the seismic performance of monolithic construction (emulative) or show improved seismic performance with the use of rocking connections (nonemulative). This paper presents findings from half-scale experimental testing of one emulative and two nonemulative precast column-footing connections. The two nonemulative connections were designed and detailed to sustain limited damage that can be rapidly and cost-effectively repaired using predefined methodologies. The tested connections showed promising results for use in regions of moderate to high seismicity; however, further developments of the proposed construction and repair methodologies are required for their full potential to be realized. © 2016 American Society of Civil Engineers.

Nicholls K.H.,Opus International Consultants
Geotechnical Engineering for Infrastructure and Development - Proceedings of the XVI European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2015 | Year: 2015

Treatment of ground underlain by shallow coal mine workings for new development is a reasonably common form of remedial ground engineering. The most common form of treatment comprises "proof drilling and grouting" involving drilling into the problematic horizon on a grid pattern and pumping in a combination of grout and/or bulk infill materials, mixed from gravel, sand, cement, PFA and water, mixed to suit the particular application. The need for treatment is based on some commonly held principles (perhaps better described as beliefs) that arise from our understanding of risks associated with the failure mechanisms of mine floor, pillar and/or roof. The key parameter in determining the need for treatment is the "10 X seam thickness" criterion which states that a worked seam should not pose a problem if overlain by 10 times its thickness of competent roof strata. A recently discovered set of Victorian lantern slides illustrate a number of key features associated with pillar and stall working of coal. These allow us to consider the suitability of the 10 X seam thickness criterion against observations based on the observed working methods, and suggest a somewhat different expression for limiting cover, with a fixed lower limit of 20m of competent strata. These conclusions are supported by a review of historic text book documentation. © The authors and ICE Publishing: All rights reserved, 2015.

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