Owens P.N.,University of Northern British Columbia |
Blake W.H.,University of Plymouth |
Giles T.R.,British Columbia Ministry of forests |
Williams N.D.,URS Infrastructure and Environment UK Ltd
Journal of Soils and Sediments | Year: 2012
Purpose: Wildfires represent one of the major natural disturbances within forested landscapes and have potential implications for the quality and function of downstream aquatic ecosystems. This study aimed to determine if a wildfire in a mountainous, forested watershed in British Columbia, Canada, caused a change in the dominant sediment source in the immediate 1-2 years following the wildfire, and if the sediment sources changed over the medium term (3-7 years) as the landscape recovered. Materials and methods: Source materials (surface soil, subsurface soil and channel bank material) and fluvial (suspended and channel bed) sediment samples were collected over the period 2004 to 2010 from a watershed burnt by a wildfire in 2003, and from an adjacent watershed that was not impacted by the fire. Samples were analysed for the fallout radionuclides (FRNs) caesium-137 (137Cs) and unsupported lead-210 (210Pbun). An unmixing model was used to calculate the relative source contributions of the fluvial sediment samples. Results and discussion: 137Cs and 210Pbun were concentrated in the upper layers of surface soils in both watersheds and were statistically different to concentrations in subsurface and channel bank material. In the burnt watershed, FRN concentrations were greatest in the ash layer. Sediment sources as determined by the unmixing model were 100 % subsurface/channel bank material in the unburnt watershed, while in the burnt watershed 8.5 ± 2.5 % was derived from surface soils. In both watersheds, there were no major changes in the relative contributions from surface soil and from subsurface/channel bank material over the period 2004 to 2010. Thus, while the wildfire did cause a change in sediment sources, it was fairly subtle and did not conform to the effects following wildfire described for other studies in contrasting environments, which typically document a major increase in hillslope contributions relative to channel bank sources. Conclusions: There was a limited response in terms of fine-grained sediment sources (and also sediment fluxes) in the burnt watershed. The reason for this muted response to a severe wildfire is likely to be the lack of precipitation, especially winter precipitation and the associated snowmelt, in the first year following the wildfire. Thus while the landscape was primed for erosion and sediment transport, the lack of a driving force meant that there was a limited immediate post-fire sediment response. © 2012 The Author(s).
Young M.,URS Infrastructure and Environment UK Ltd. |
Hayman-Joyce J.,URS Infrastructure and Environment UK Ltd. |
Kim S.H.,Hyundai Engineering
Proceedings of the Coastal Engineering Conference | Year: 2012
Detailing and optimization of the toe reinforcement is presented as a case study from the construction of the 5.2km long main breakwater for the new Colombo South Harbour in 18m water depth. During the breakwater design the environmental constraints on supply of large rock armour were recognized, and CORE-LOC" single layer concrete armour units were selected for the primary armour protection. During construction, supply of relatively small quantities of 8-12t rock for use in the toe reinforcement became an issue, and use of CORE-LOC" units placed on the flat rock armour apron as an alternative to rock armour toe reinforcement was investigated and implemented. This use is unusual as there is no in-plane compression between units as found when they are placed on the slope. A site based prototype scale trial was conducted to evaluate placing method and criteria, and an "alternate opposing cannon" pattern placement, in rows going seaward from the primary armour, was successful. Packing density and unit spacing is the same as for the primary armour. Hydraulic stability of this alternative toe reinforcement was verified in 2D physical hydraulic model testing.
Dehdezi P.K.,URS Infrastructure and Environment UK Ltd
Journal of Materials in Civil Engineering | Year: 2014
This paper considers the effect of the thermophysical properties of concrete on temperature distributions and stresses developed in concrete pavements. The temperature distributions in concrete pavements, composed of different thermophysical properties, were calculated using a finite-difference model. These temperatures were then fed into a finite-element model as thermal loads in order to calculate tensile stresses in the concrete. It was found that the thermophysical properties of concrete can significantly influence the magnitude of tensile stresses and, subsequently, the thickness of the concrete slab. Concrete with higher thermal conductivity and diffusivity (e.g., incorporating high conductive aggregates and/or metallic fibers) will experience much more uniform temperature and, as a result, a smaller tensile stress will be developed in the concrete. Increasing the thermal conductivity of concrete from 1.2 W=mK (concrete containing limestone aggregates) to 3.6 W=mK (concrete containing quartzite aggregates and 1% metallic fibers) could result in a 25% reduction of the concrete slab thickness. © 2014 American Society of Civil Engineers.
Finnie S.B.,URS Infrastructure and Environment UK Ltd
7th International Conference on Maintenance and Rehabilitation of Pavements and Technological Control, MAIREPAV 2012 | Year: 2012
Road authorities are currently faced with the challenge of reducing their carbon footprint in response to Climate Change at a time when many also have to cope with reduced capital and maintenance budgets due to the economic climate. When considering alternative maintenance options, those strategies with the lowest capital or whole life cost are not always those with the lowest carbon footprint. This gives the road authorities a dilemma when it comes to selecting the optimum maintenance option to meet their business objectives. Understanding the relative cost and carbon impact of alternative design options is, therefore, critical to managing these competing demands. URS has developed an application (app), branded WLCO2T, which measures the whole life cost and whole life carbon footprint of alternative maintenance strategies for pavement assets over a 60-year analysis period. WLCO2T includes a database of maintenance activities for flexible, composite and rigid pavements that contains cost data and greenhouse gas emissions factors. The User builds a maintenance strategy by allocating maintenance activities to a specific year. WLCO2T then calculates the: capital cost, operational cost, whole life cost, capital carbon footprint, operational carbon footprint and whole life carbon footprint. The outputs of the app provides road authorities with high-level decision making information which is intended to be used at preliminary design stage to select the preferred option or several options for further design development. The app can also be used to determine the optimum year in which to carry out the maintenance.
Roach I.,URS Infrastructure and Environment UK Ltd
Impact Assessment and Project Appraisal | Year: 2013
This research examined public understanding of the environmental effects of a proposed energy-from-waste facility from the perspective of an Environmental Impact Assessment (EIA) practitioner. Disparities were identified between the public perceptions examined and the results of the EIA, notably on air quality and health effects from chimney emissions; the facility's noise characteristics; traffic volumes and associated air quality, noise and amenity effects; daylight, sunlight and overshadowing effects; and cumulative effects. Lessons for EIA practitioners are drawn that enable better appreciation of specific areas of public concern. Ways in which communications might be improved in future EIAs to aid public understanding are also identified. © 2013 Copyright IAIA.
Grenfell J.,University of Nottingham |
Ahmad N.,University of Nottingham |
Airey G.,University of Nottingham |
Collop A.,University of Nottingham |
Elliott R.,URS Infrastructure and Environment UK Ltd
International Journal of Pavement Engineering | Year: 2012
The saturation ageing tensile stiffness (SATS) procedure is the first laboratory asphalt mixture durability protocol to combine moisture damage and oxidative ageing during the conditioning of asphalt mixtures prior to mechanical testing. However, the application of the SATS procedure has tended to be predominantly targeted at base materials with relatively hard binders and overall high stiffness modulus requirements and is considered potentially too severe for more standard asphalt mixtures. This research study focused on understanding the effect of changes to the SATS conditioning parameters on the relative moisture damage assessment performance of asphalt mixtures, particularly softer binder, high binder content and, finally, low air void content mixtures. Using four different aggregate types, together with hard 10/20 pen and softer 40/60 pen bitumen, the parameters of pressure, temperature and duration were altered, either one at a time or in combination, to arrive at a suitable combination for testing more commonly used 40/60 pen material. The optimum combination of parameters to allow the SATS procedure to be used for a wide range of typically used asphalt mixtures was found to be 0.5MPa pressure, 85°C temperature and 24h duration. The revised SATS durability conditioning protocol was still able to successfully discriminate between poor moisture susceptible aggregate and good material. © 2012 Copyright Taylor and Francis Group, LLC.
Glennon D.,URS Infrastructure and Environment UK Ltd. |
Brown A.,URS Infrastructure and Environment UK Ltd.
Structural Engineer | Year: 2013
In 2012, URS with lead designer HLN Architects was appointed to develop a new housing block and education building at Her Majesty's Young Of ender Institution (HMYOI) Cookham Wood in Rochester, Kent. The project comprised the construction of a new L-shaped, three-storey housing block to accommodate 179 young people, including the provision of full disabledaccess cells with suitable bathrooms, and a new education building with associated ancillary works. The scope of the project also included new security fencing around exercise yards, access roads and new cross-site services required to supply the additional facilities (Figure 1). Working with HLN Architects, the project was planned so that construction work could be carried out without major impact on the establishment and its normal operating routines, with access available from adjoining roads. The Cookham Wood project was the first of four Ministry of Justice (MoJ) projects in its Level 2 Building Information Modelling (BIM) 'Early Adopter Programme', part of MoJ's strategy for meeting the Government's plan to roll out BIM Level 2 across all public sector projects by 2016. This article describes URS' experience, from high-level thinking about BIM on this pilot scheme, to the realities of delivering full BIM models in a tight (six week) programme.
Skinner C.,URS Infrastructure and Environment UK Ltd |
Shields P.,URS Infrastructure and Environment UK Ltd |
Billin H.,URS Infrastructure and Environment UK Ltd
42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life | Year: 2013
This paper presents a discussion of best practice for undertaking large scale baseline sound surveys, based on the experience of the URS Acoustics and Vibration Team over many projects. A set of processes have been developed to ensure consistency in data collection and processing, and provide robust data on the existing acoustic climate that is fit for purpose for use as baseline for Environmental Statements or to provide information on long- Term variations in sound levels. Approaches include the use of GIS systems to store, manage and visualise measurement locations, standardised measurement procedures with standard forms to ensure that methods are complied with and all necessary data are recorded. For long- Term measurements sites, multiple visits are recommended to allow detailed notes of the soundscape to be taken at different times of day. Geo-referenced photographs should be taken of all monitoring sites and their surroundings. The use of audio recordings to allow for future subjective and/or quantitative analysis of the sound climate is also discussed. Suggested methods are included for the optimum utilisation of the measured data from long- Term and short term monitoring satellite locations, together with the processing of these results. Copyright © (2013) by Austrian Noise Abatement Association (OAL).
Briggs G.,URS Infrastructure and Environment UK Ltd. |
Cooper G.A.,URS Infrastructure and Environment UK Ltd. |
Bell D.,URS Infrastructure and Environment UK Ltd.
Maintaining the Safety of Our Dams and Reservoirs - Proceedings of the 18th Biennial Conference of the British Dam Society | Year: 2014
The Woodburn Reservoir system in the hills above Carrickfergus, Northern Ireland, comprises seven impounding reservoirs in two cascades. These water supply reservoirs are managed by Northern Ireland Water (NIW) and they supply a wide area of North Belfast and South Antrim. The structures date from 1868 and include designs by both Macassey and Bateman.The most recent Section 10 Inspection Reports recommended investigations into the operation and condition of the reservoir scour pipework and highlighted concerns regarding the access arrangements within the associated towers.This paper outlines the findings of the resulting investigation works and the subsequent refurbishment works at the first two sites with particular reference to the lessons learned in the refurbishment of historic structures and pipework. It will also comment on the programming challenges associated with temporarily removing reservoirs from service and the environmental issues associated with emptying reservoirs to provide safe access for repairs.
Szymanek E.,Czestochowa University of Technology |
Blaszczyk T.,Czestochowa University of Technology |
Hall M.R.,University of Nottingham |
Dehdezi P.K.,URS Infrastructure and Environment UK Ltd |
Leszczynski J.S.,Czestochowa University of Technology
Granular Matter | Year: 2014
This article demonstrates the solution to the problem of the passage of air through the external wall barrier and the influence of the materials type and its layer arrangement on heat conductivity, in respect of building heat losses. It shows how the temperature changes inside the wall barriers and in a room while the external temperature changes. Also, this article presents the mathematical model based on fractional differential equation describing the analysed phenomenon. © The Author(s) 2014.