Speirs K.M.,Mott MacDonald Ltd.
Dams and Reservoirs | Year: 2016
Mott MacDonald Bentley Ltd (MMB) has carried out modification works to an impounding reservoir in Yorkshire, to enable the overflow system to safely pass the probable maximum flood (PMF) and maintain compliance with the Reservoirs Act 1975. The works, included lining the existing spillway and stilling basin with reinforced concrete. This logistically complex £1·8 million scheme is a key example of MMB’s use of off-site construction and application of innovation to overcome significant challenges that reservoir sites can present. The reservoir has a very steep spillway, which presented MMB with a limited number of options in terms of accessing the spillway and safely constructing the proposed, ensuring a high-quality finished product. With a well-developed track record of precast concrete (PCC) construction on reservoir projects, the MMB team were inspired to push the boundaries of current design and construction methodologies. They developed a PCC ‘U-section’ product to line the spillway, installed via a unique rail and winch system. This paper describes the design and construction of the U-sections and associated installation system, including testing of the joint system to prove hydraulic performance. This design resulted in increased speed of construction, reduced costs and zero injuries on site. © ICE Publishing.
Roohnavaz C.,Mott MacDonald Ltd.
Proceedings of the Institution of Civil Engineers: Geotechnical Engineering | Year: 2010
The depot of the MRT Chaloem Ratchamongkhon line in Bangkok was designed and constructed as an elevated concrete platform structure of some 250 000 m2, supported by 17 000 driven prestressed, precast concrete piles. The design of piles considered full hydrostatic pressure in the long term, with soft clay negative skin friction due to the ongoing land subsidence. These requirements required that the piles be founded sufficiently in a deep sand stratum in order to ensure an adequate factor of safety against bearing capacity failure. This paper reports on the rigorous construction control procedures that were implemented with the aid of a pile driving analyser, in order to ensure that the design requirements were achieved. The procedures included monitoring the drive system performance, driving stresses, assessment of pile integrity and evaluation of pile capacity. The timely development and implementation of these procedures was fundamental to the early completion of piling, and to confidence in the integrity and capacity of the piles.
Susetyo J.,Mott MacDonald Ltd. |
Gauvreau P.,University of Toronto |
Vecchio F.J.,University of Toronto
ACI Structural Journal | Year: 2011
Ten 35 × 35 × 2.75 in. (890 × 890 × 70 mm) concrete panels were tested under in-plane pure-shear monotonie loading conditions to evaluate the effectiveness of steel fibers in meeting minimum shear reinforcement requirements for concrete elements. The test results indicate that concrete elements exhibiting ductile behavior, sufficient shear strength, and good crack control characteristics can be obtained with an adequate addition of steel fibers, meeting or exceeding the level of performance achievable using codeprescribed minimum amounts of conventional shear reinforcement. Fiber aspect ratio, fiber length, fiber tensile strength, fiber volume content, and concrete compressive strength are found to influence the shear performance of fiber-reinforced concrete (FRC) to varying extents. Details and results are provided. © 2011, American Concrete Institute. AU rights reserved.
Agency: GTR | Branch: EPSRC | Program: | Phase: Research Grant | Award Amount: 557.66K | Year: 2012
There are a variety of aerodynamic effects associated with train design and operation - the determination of aerodynamic drag, the effect of cross winds on train stability, pressure transient loading on trackside structures, the physiological effect of tunnel pressure transients, the effect of train slipstreams and wakes on waiting passengers and trackside workers etc. The magnitude of these effects broadly increases as the square of the vehicle speed and thus with the continued development of high speed train lines aerodynamic effects will become more significant in terms of design and operation. Now it can be hypothesised that the techniques that have been used to predict aerodynamic effects in the past (wind tunnel and CFD methods) are likely to determine magnitudes of pressures, velocities, forces etc. that are higher than those observed in practice, where other effects - such as track roughness, variability in meteorological conditions etc. are likely to usually obscure aerodynamic effects to some extent and, because of this, some of the current design methodologies are unnecessarily restrictive and/or conservative. Thus the aim of the current project is to investigate and measure a range of aerodynamic phenomena observed in real train operation, both relative to the train and relative to a fixed point at the trackside, and to compare how such effects match model scale measurements and various types of CFD calculation, and thus to test the validity, or otherwise, of the above hypothesis. This will be achieved through the instrumentation of the Network Rail High Speed Measuring Train to measure aerodynamic effects, as the train carries out its normal duty cycle around the UK rail network. Also trackside instrumentation will be installed at a suitable site that will allow off-train phenomena to be measured. Calibration wind tunnel, CFD and moving model tests will be carried out in the conventional way for comparison with data measured at full scale. The full scale, model scale and computational trials will be carried out by experienced RFs and will provide data for two doctoral studies, one of which will investigate how the train based measurements of cross wind forces, pressure transients etc compare with those predicted by conventional methodologies, and one of which will investigate how the track side measurements compare with conventional test results. The investigators will synthesise the results and make recommendations for future aerodynamic test methods.
Agency: GTR | Branch: EPSRC | Program: | Phase: Research Grant | Award Amount: 634.73K | Year: 2015
Recent flooding events such as those of winter 2013/14 in the South West of UK have highlighted the importance of having greater resilience in our transport infrastructure. The failure of bridges or even a reduction in service during and in the aftermath of floods can lead to significant direct and indirect costs to the economy and society, and hamper rescue and recovery efforts. For example, 29 bridges collapsed or were severely damaged during the 2009 floods in Cumbria leading to nearly £34m in repair and replacement costs, and significantly larger economic and societal costs. This research aims to enhance the resilience of our transport infrastructure by enabling practitioners to assess the risks to bridges from debris accumulation in the watercourse, a leading cause of bridge failure or damage during floods both in the UK and world-wide. It will address an important industry need as there is currently no guidance available for practitioners to evaluate the hydrodynamic effects of debris blockage at bridges and in particular, at masonry bridges, which are most susceptible to debris blockage. Floating debris underneath or upstream of a bridge can significantly increase downstream flow velocities, which can worsen scour around piers and abutments. It can also increase water levels on the bridge and thereby cause large lateral and uplift pressures, which are especially problematic for masonry bridges since they rely on self-weight of masonry and fill to transfer load. This project will aim to understand and characterize the hydrodynamic effects of debris blockage through a combination of laboratory experiments in flumes and computational fluid dynamics (CFD) modelling. It will then develop a risk-based approach for assessing the scour, and uplift and lateral forces at individual bridges due to debris blockage during flood conditions, and incorporate this approach within existing guidance for the assessment of bridges under hydraulic action. The project will be arried out by a multi-disciplinary research team with a strong track record of generating impact, and assisted by an industry consortium composed of major stakeholders involved in UK bridge management.