Civil and Environmental Engineering - Conference Items
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Item Hydraulic permeability and ageing behaviour of Dublin Port Tunnel(International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE), 2022-05) Wang, Chao; Li, Zili; Friedman, Miles; Science Foundation Ireland; Transport Infrastructure IrelandTunnel hydraulic deterioration has been widely reported and investigated in many past studies where, nevertheless, the tunnel lining permeability was assumed as constant and the time-dependent hydraulic degradation process was neglected. To investigate the hydraulic ageing behaviour of Dublin Port Tunnel, in this paper, a modified ground-lining relative permeability analytical model was derived and current deteriorated lining permeability was estimated using field monitoring water flow data. Compared with the initial watertight status of Dublin Port Tunnel, the current hydraulic state of the tunnel was found to be partially permeable after more than a decade’s operation. The results from numerical simulations showed that the assumption of a constant hydraulic permeability during the lifetime of tunnel structures may not evaluate the ageing tunnel deformational performance process realistically. It is important to consider the effect of time-dependent hydraulic deterioration process on tunnel performance.Item Using model selection and reduction to develop an empirical model to predict energy consumption of a CNC machine(Springer Nature Switzerland AG, 2022-10-17) Morris, Liam; Clancy, Rose; Hryshchenko, Andriy; O’Sullivan, Dominic; Bruton, Ken; Margaria, Tiziana; Steffen, Bernhard; Horizon 2020With an ever growing need to reduce energy consumption in the manufacturing industry, process users need to become more aware on how production impacts energy consumption. Computer numerically controlled (CNC) machining tools are a common manufacturing apparatus, and they are known to be energy inefficient. This paper describes the development of an empirical energy consumption model of a CNC with the aim of predicting energy consumption based on the number of parts processed by the machine. The model can then be deployed as part of a decision support (DS) platform, aiding process users to reduce consumption and minimise waste. In using the Calibrated Model Method, the data undergoes initial preparation followed by exploratory data analysis and subsequent model development via iteration. During this analysis, relationships between parameters are explored to find which have the most significant on energy consumption. A training set of 191 datapoints yielded a linear correlation coefficient of 0.95, between the power consumption and total units produced. RMSE, MAPE and MBE validation test yielded results of 0.198, 6.4% and 2.66% respectively.Item Structure design and assessment of a floating foundation for offshore wind turbines(American Society of Mechanical Engineers (ASME), 2019-11-03) Ye, Q.; Cheng, S.; Kim, B.; Collins, K.; Iglesias, GregorioThis paper summarizes the assessment of the structural analysis and design of a floating foundation for offshore floating wind turbine (FWT) based on DNVGL standard and Eurocode in terms of economy and reliability. The wind loads are calculated using empirical equations. The wave loads are obtained and verified using various methods including hand calculation, AQWA and Flow-3D. It is found that the shell thickness could be reduced significantly by introducing the stiffeners (stringer or ring), which can decrease the weight of the hull and lower the cost. While DNVGL and Eurocode yield similar design solutions if using plane shell structures, Eurocode significantly underestimates the buckling resistance of stiffened cylindrical shells.Item Effect of chloride exposure condition on the performance of concretes containing PFA(Purdue University, 2018) Ryan, Paraic C.; O'Connor, Alan J.; Transport Infrastructure Ireland; Irish Research Council; European CommissionOver the past number of decades the use of different supplementary cementing materials have been investigated, with a view to increasing the resilience of reinforced concrete to chloride-induced corrosion. The slow nature of chloride-ion ingress has meant much of the information available on the relative performance of different concretes has been derived from accelerated testing, with the majority of these tests conducted under fully saturated conditions. While there is merit to such practices, there is also a need to examine the relative performance of different concretes under unsaturated conditions. This need is highlighted by the fact that reinforced concrete elements in the splash, spray and tidal zones of marine structures, which are subject to wetting and drying cycles, are most susceptible to reinforcement corrosion. This paper examines the effect of different wetting and drying cycles on the relative performance of OPC self-compacting concrete, and self-compacting concrete containing PFA. This was achieved through three sets of salt fog chamber tests, each with different wetting and drying cycles. It was found that, when compared to the OPC option, the relative chloride ingress resistance of the OPC + PFA concrete reduced when the degree of drying in the test increased. This indicates that fully saturated tests may somewhat overestimate the practical benefits of incorporating PFA into concrete in chloride rich environments.Item Distributed fibre optic strain sensing of CERN infrastructures in the molasse region(Icelandic Geotechnical Society (IGS), 2019) Di Murro, V.; Soga, K.; Fern, E. J.; Pelecanos, L.; Li, Zili; Scibile, L.; CERN; Engineering and Physical Sciences Research Council; Innovate UKThe European Centre for Nuclear Research (CERN) is a large underground laboratory and it is home to two large particle accelerators, including the «Large Hadron Collider» (LHC). The particles travel at the speed of light through a series of tunnels which must comply with the high serviceability requirements. However, the underground facilities have expanded over a period of 40 years with new tunnels, shafts and caverns. Structural ageing and deterioration of the infrastructure can alter the drainage conditions around tunnels and this can cause, in turn, excess deformation of the tunnels and serviceability issue for the particle accelerators. A remote monitoring system based on distributed fibre-optic strain sensing technology has been implemented in some of the concrete-lined tunnels in order to gain insight in the long-term mechanical behaviour of the underground system. This paper presents the results of the monitoring programme and the results show a slow development of ovalisation of the tunnel over a period of three years.