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Melbourne, Australia

Chen K.,URS Australia | Chapman G.A.,Golder Assoc.
Australian Geomechanics Journal | Year: 2014

This paper presents a case history of a preliminary liquefaction assessment for bridge pile foundations for the Breakwater Road Realignment Bridge in Geelong, Victoria. The bridge site is situated on an alluvial plain of the Barwon River delta and is underlain by a layer of very loose sand sediments. Concerns were raised regarding the potential liquefaction of the very loose sand sediments and the potential impact that soil liquefaction may have on the proposed pile foundations of the bridge. A soil liquefaction assessment was carried out using the procedures initially developed in the 1970s and 1980s (Seed and Idress 1971 and 1982) and lately revised by Youd and Idress et al. in 2001. While the majority of the piled foundations at the site were assessed not to be at risk of liquefaction, two pier locations where very loose sand was encountered were assessed to be potentially liquefiable under the design earthquake loading. At these locations, the pile groups were designed under earthquake loading to allow for the potential liquefaction of the loose layers. Source

Phillips M.A.,URS Australia | Lesleighter E.J.,Hydraulics Engineering Specialist
Labyrinth and Piano Key Weirs II, PKW 2013 - Proceedings of the 2nd International Workshop on Labyrinth and Piano Key Weirs 2013 | Year: 2014

A spillway upgrade conceptual design and selection process was undertaken to identify options for upgrading the Dartmouth Dam to pass the Probable Maximum Flood (PMF). The piano key weir was initially developed from the limited available publications on the weir design, and further developed with the use of a 1:60 scale model. The piano key weir, a variation of the labyrinth weir, is a passive spillway that utilises a total weir length several times that of the existing spillway width. For the Dartmouth Dam study, the piano key weir design that was developed consisted of a 7-cycle, 9m high structure, with a total weir length of nearly 600 m, or more than 6 times the existing spillway width of 91 m. The spillway was designed to pass the routed PMF outflow of approximately 11,500m3/s with a head of approximately 11m. ©2014 Taylor & Francis Group. Source

Wang L.,Queensland University of Technology | Jayaratne R.,Queensland University of Technology | Heuff D.,URS Australia | Morawska L.,Queensland University of Technology
Atmospheric Environment | Year: 2010

A composite line source emission (CLSE) model was developed to specifically quantify exposure levels and describe the spatial variability of vehicle emissions in traffic interrupted microenvironments. This model took into account the complexity of vehicle movements in the queue, as well as different emission rates relevant to various driving conditions (cruise, decelerate, idle and accelerate), and it utilised multi-representative segments to capture the accurate emission distribution for real vehicle flow. Hence, this model was able to quickly quantify the time spent in each segment within the considered zone, as well as the composition and position of the requisite segments based on the vehicle fleet information, which not only helped to quantify the enhanced emissions at critical locations, but it also helped to define the emission source distribution of the disrupted steady flow for further dispersion modelling. The model then was applied to estimate particle number emissions at a bi-directional bus station used by diesel and compressed natural gas fuelled buses. It was found that the acceleration distance was of critical importance when estimating particle number emission, since the highest emissions occurred in sections where most of the buses were accelerating and no significant increases were observed at locations where they idled. It was also shown that emissions at the front end of the platform were 43 times greater than at the rear of the platform. Although the CLSE model is intended to be applied in traffic management and transport analysis systems for the evaluation of exposure, as well as the simulation of vehicle emissions in traffic interrupted microenvironments, the bus station model can also be used for the input of initial source definitions in future dispersion models. © 2010 Elsevier Ltd. Source

Wang L.,Queensland University of Technology | Morawska L.,Queensland University of Technology | Jayaratne E.R.,Queensland University of Technology | Mengersen K.,Queensland University of Technology | Heuff D.,URS Australia
Atmospheric Environment | Year: 2011

Measurements of airborne particle number size distributions, particle number and PM2.5 concentrations were conducted at two bus stations of different designs: open station and canyon station, operated according to the same timetables and fleet compositions, as well as at a reference point in Brisbane, Australia. Simultaneous traffic and meteorological parameters were also monitored, aiming to quantify particle characteristics and investigate the impact of station design and meteorological conditions on particle emissions at the two bus stations. It was found that there was no significant difference in average particle number concentrations in the size range 7-3000nm (PN7-3000) between the two stations (fine days: p=0.90 and rainy days: p=0.80), and that PN50-120 contributed to the largest proportion of particle number concentrations. PN20-30 were observed to increase at the open station during all time periods, except 0:00-7:00, which is likely to be attributed to the lower average daily temperature at the open station (around 7°C lower than at the canyon station). During precipitation, it was found that particle number concentration in the size range 25-250nm decreased greatly, and the average daily reduction in PM2.5 concentration on rainy days compared to fine days was 44.2% and 22.6% at the open and canyon station, respectively. The effect of ambient wind speeds on particle number concentration was also examined, and no relationship was found between particle number concentration and wind speed for the entire measurement period. In addition, 33 pairs of average half-hourly PN7-3000 concentrations were calculated and identified at the two stations, during the same time of a day, and with the same ambient wind speeds and precipitation conditions. The results of a paired t-test showed that the average half-hourly PN7-3000 concentrations at the two stations were not significantly different at the 5% confidence level (t=0.06, p=0.96), which indicates that the different station designs were not a crucial factor for influencing PN7-3000 concentrations. This finding implies that the timescale of dispersion at the bus stations was comparatively long, and that the source contribution was more important compared to the atmospheric dispersions associated with different station designs. © 2010 Elsevier Ltd. Source

Shiri J.,University of Tabriz | Makarynskyy O.,URS Australia | Kisi O.,Erciyes University | Dierickx W.,Geraardsbergsesteenweg 18 | Fard A.F.,University of Tabriz
Journal of Waterway, Port, Coastal and Ocean Engineering | Year: 2011

Sea level estimates are important in many coastal applications and port activities. This paper investigates the ability of a neuro-fuzzy (NF) model to predict sea level variations at a tide gauge site in the Hillarys Boat Harbour, Western Australia. In the first part of the study, previously recorded sea levels were used as input to estimate current sea levels. The results showed an acceptable level of NF model accuracy. In the second part of the study, NF models were implemented to forecast sea levels averaged over 12- and 24-h time periods, three time steps ahead. The NF forecasts were compared with those of artificial neural networks (ANNs) for the same data set. The results show that the NF approach performed better than the ANN in half-daily 12-, 24-, and 36-h sea level predictions. The traditional linear regression and autoregressive models were also tested for comparison, and they demonstrated their inferiority to the results of other techniques. © 2011 American Society of Civil Engineers. Source

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