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Napier, New Zealand

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

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. Source

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

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. Source

Herrington P.R.,Opus International Consultants

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. Source

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

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. Source

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

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. Source

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