http://hdl.handle.net/10197/2019 2013-05-21T03:58:28Z http://hdl.handle.net/10197/4225 Vibrational Spectroscopy for Analysis of Water for Human Use and in Aquatic Ecosystems Gowen, Aoife; Tsenkova, R.; Bruen, Michael; O'Donnell, O'Donnell, C. P. (Colm P.) Maintaining a clean water supply is one of the key challenges facing humanity today. Pollution, over-use and climate change are just some of the factors putting increased pressure on our limited water resources. Contamination of the water supply presents a high risk to public health, security and the environment; however, no adequate real-time methods exist to detect the wide range of potential contaminants. There is a need for rapid, low cost, multi target systems for water quality monitoring. Information rich techniques such as vibrational spectroscopy have been proposed for this purpose. This review presents developments in the applications of vibrational spectroscopy to water quality monitoring over the past 20 years, identifies emerging technologies and discusses future challenges. 2012-11-12T00:00:00Z http://hdl.handle.net/10197/4223 Parameter sensitivity of a watershed-scale flood forecasting model as a function of modelling time-step O'Loughlin, Fiachra; Bruen, Michael; Wagener, Thorsten Despite significant developments, the simple, lumped, conceptual, rainfall-runoff model is still widely used for flood forecasting. What may not be appreciated is that, while such models can often be calibrated to give reasonable forecasts of flood flows, both parameter values and the fluxes of water through individual model components change significantly with the time step used. This means that such models should be used with caution for studies which require “internal” information, such as hydrograph separation or water quality studies that depend on knowing the fluxes through individual flow routes through the model and in studies which try to relate parameter values to physical features of the catchment. To demonstrate this time-scale limitation, a parameter sensitivity analysis was performed on a typical lumped conceptual model (SMARG) applied to a small rural catchment on the Irish East Coast for a number of different time-steps, flow regimes and evaluation metrics. A global sensitivity analysis method (GUI-HDMR, is applied to calculate sensitivity indices which varied greatly with time-step and evaluation metric used. The sensitivity of parameters also differed for different flow regimes. Care should be taken in using internal information and calibrated parameter in conceptual models because of the strong dependence on time-step. 2012-07-10T00:00:00Z http://hdl.handle.net/10197/4221 The impact of a catastrophic storm event on benthic macroinvertebrate communities in upland headwater streams and potential implications for ecological diversity and assessment of ecological status Feeley, Hugh B.; Davis, Stephen; Bruen, Michael; Blacklocke, Sean; Kelly-Quinn, Mary Upland headwater streams are dynamic systems, responding rapidly to changes in climatic conditions. This study examined the effects of a catastrophic rainfall event, that occured on 24 October 2011 on the east coast of Ireland, on the macroinvertebrate community composition and structure of four headwater streams in the river Liffey catchment located in the Wicklow Mountains. The ecological status before and after the storm were also evaluated. The water level and pH of each stream were recorded using continuous monitoring equipment, while rainfall data for the study period were sourced from a local weather station. Benthic macroinvertebrates were investigated before and after the storm event using Surber sampling. Results showed rapid and large increases in water level and significant declines in stream pH in response to intensive rainfall during the storm. The high water levels also caused major physical damage and abrasion in all four streams, that significantly altered instream habitats. The storm event induced significant losses to the richness and/or density of most taxonomic groups, with the exception of the Plecoptera. Furthermore, the overall community composition and structure changed significantly, most likely as a result of physical disturbance, given the relative persistence of acid-sensitive taxa and the relatively short period of harsh acidic conditions (<5 pH). Interestingly however, the ecological status of each of the four study sites, tested using Stream Risk Score (SSRS), Biological Monitoring Working Party (BMWP) and the Average Score Per Taxon (ASPT) indices, was unaltered by the loss in richness and densities. This was likely a result of the maintenance of plecopteran richness and the absence of organic pollution, thus highlighting the need to develop appropriate indices to assess the ecological status of streams and rivers affected by physical disturbance caused by large storm events. Ultimately, catastrophic storm events in upland headwater streams have potentially major implications for the maintenance of regional macroinvertebrate diversity within affected regions. 2012-07-24T00:00:00Z http://hdl.handle.net/10197/4201 Derivation of a national fuzzy phosporous export model using 84 Irish catchments Nasr, Ahmed Elssidig; Bruen, Michael Implementation of appropriate management strategies to mitigate diffuse phosphorus (P) pollution at the catchment scale is vitally important for the sustainable development of water resources in Ireland. An important element in the process of implementing such strategies is the prediction of their impacts on P concentrations in a catchment using a reliable mathematical model. In this study, a state-of-the-art adaptive neuro-fuzzy inference system (ANFIS) has been used to develop a new national P model capable of estimating average annual ortho-P concentrations at un-gauged catchments. Data from 84 catchments dominated by diffuse P pollution were used in developing and testing the model. Six different split-sample scenarios were used to partition the total number of the catchments into two sets, one to calibrate and the other to validate the model. The k-means clustering algorithm was used to partition the sets into clusters of catchments with similar features. Then for each scenario and for each cluster case, 11 different models, each of which consists of a linear regression sub-model for each cluster, were formulated by using different input variables selected from among six spatially distributed variables including phosphorus desorption index (PDI), runoff risk index (RRI), geology (GEO), groundwater (GW), land use (LU), and soil (SO). The success of the new approach over the conventional lumped, empirical, modelling approach was evident from the improved results obtained for most of the cases. In addition the results highlighted the importance of using information on PDI and RRI as explanatory input variables to simulate the average annual ortho-P concentrations. 2013-01-15T00:00:00Z http://hdl.handle.net/10197/4172 Bankfull discharge and recurrence intervals in Irish rivers Ahilan, Sangaralingam; O'Sullivan, J. J.; Bruen, Michael; Brauders, Neill; Healy, Darren Different definitions of the bankfull condition in rivers are based on morphological characteristics, boundary conditions and geometrical properties. Consequently, the magnitude and associated return period of the bankfull discharge can be ambiguous. Knowledge of this discharge is important in index flood estimation and subsequent regional flood frequency analysis. This study investigates bankfull discharges and recurrence intervals at 88 locations in the Irish river network using a combination of surveyed bankfull levels, rating curves and equations and photographic records at the sites in question. Catchments ranged in area from approximately 23 km2 to 2778 km2. Recurrence intervals were determined by fitting generalised extreme value (GEV) distributions to the annual maximum flow series at the sites investigated. These intervals were found to be less than 2 years (the median annual flood) at 42 stations (48%) and less than 2·33 years (the mean annual flood assuming a GEV type 1 distribution) at 47 stations (53%). Higher return periods of between 2·33 and 10 years and 10 and 25 years were observed at a further 20% and 6% of locations respectively. Using multivariate regression analysis, the computed bankfull discharges are correlated with catchment descriptors and three expressions are presented for estimating bankfull flows. 2013-01-01T00:00:00Z http://hdl.handle.net/10197/4171 The Shaft Capacity of Displacement Piles in Clay: A State of the Art Review Doherty, Paul; Gavin, Kenneth The rapid expansion of the offshore wind sector, coupled with increasing demand for high rise structures, has placed renewed demand on the driven piling market. In light of this industry growth, this paper reviews the evolution of design approaches for calculating the shaft capacity of displacement piles installed in cohesive soils. The transition from traditional total stress design towards effective stress methods is described. Complex stress–strain changes occur during pile installation, equalisation and load testing and as a consequence, the selection of parameters for use in conventional earth-pressure type effective stress approaches is not straight-forward. These problems have led to the development of empirical correlations between shaft resistance and in situ tests, such as the cone penetration tests. However, many of these approaches are limited because they were developed for specific geological conditions. Significant insight into pile behaviour has been obtained from recent model pile tests, which included reliable measurements of radial effective stresses. These tests have allowed factors such as friction fatigue and interface friction to be included explicitly in design methods. Whilst analytical methods have been developed to investigate pile response, these techniques cannot yet fully describe the complete stress–strain history experienced by driven piles. The use of analytical methods in examining features of pile behaviour, such as the development of pore pressure during installation and the effects of pile end geometry on pile capacity, is discussed. 2011-07-01T00:00:00Z http://hdl.handle.net/10197/4170 Retaining walls in Dublin Boulder Clay, Ireland Long, Michael (Michael M.); Brangan, Carl; Menkiti, Christopher O.; Looby, Michael; Casey, Patrick A good number of deep excavations have been recently completed in Dublin Boulder Clay, Ireland. These have included propped walls up to 25 m deep and permanent cantilevers 7.5 m high. Experience elsewhere in the world was used to design and construct these walls. However, case history data have shown that the behaviour of the walls in Dublin Boulder Clay is very rigid and much stiffer than comparable systems worldwide. It appears this behaviour is due to the inherent natural strength and stiffness of the soil and the slow dissipation of excavation induced depressed pore pressures or suctions. There appears to be scope for developing more efficient designs and in particular for reducing propping requirements. For temporary works, the use of undrained parameters in serviceability limit state calculations together with implementation of the observational approach on site could be considered for future schemes. 2012-01-01T00:00:00Z http://hdl.handle.net/10197/4163 Weigh-in-Motion: Recent Developments in Europe Jacob, Bernard; O'Brien, Eugene J. This paper provides a review of recent European developments in WIM. Pan-European and national projects are reported plus developments in sensor technologies and system design. Recent developments in multiple-sensor WIM systems are given particular attention. The coming of prototype fully-automatic overload systems is discussed and the technologies and legal framework necessary for their success. The commercialisation of Bridge WIM in Europe since the ICWIM3 is considered and the continued development of this technology towards almost maintenance-free systems. WIM applications are also discussed including pavement and bridge design and assessment. 4th International Conference on Weigh-in-Motion - ICWIM4, Taipei, Taiwan, 20-23rd February 2005 2005-01-01T00:00:00Z http://hdl.handle.net/10197/4162 Experimental Investigation of Drive-by Bridge Inspection Kim, Chul-Woo; Isemoto, R.; Toshinami, T.; Kawatani, M.; McGetrick, P.; O'Brien, Eugene J. This study presents a vibration-based health monitoring strategy for short span bridges utilizing an inspection vehicle. How to screen health condition of short span bridges in terms of the drive-by bridge inspection is described. Feasibility of the drive-by bridge inspection is investigated through a scaled laboratory moving vehicle experiment. The feasibility of using an instrumented vehicle to detect the natural frequency and changes in structural damping of a model bridge is observed. Observations also demonstrate the possibility of diagnosis of bridges by comparing patterns of identified dynamic parameters of bridges through periodical monitoring. It is confirmed that the moving vehicle method identifies the damage location and severity well. 5th International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-5), Cancun, Mexico, 11-15 December, 2011 2011-01-01T00:00:00Z http://hdl.handle.net/10197/4161 Finite Element Model Updating Using Cross-Entrophy Dowling, Jason; González, Arturo; O'Brien, Eugene J.; Walsh, Brian J. This paper presents the potential of the cross-entropy method to surmise the properties of a simply supported beam using as input the response of the structure to a moving load. The beam model is discretised into a number of elementary beams with assumed initial statistical distributions of stiffness. Then, an optimisation procedure based on cross-entropy is employed to minimise differences between simulated measurements and the results of the theoretical finite element beam model. The procedure consists of generating a large sample of stiffness distributions for each elementary beam, and selecting those fitting the measured response best. Then, the parameters of the statistical distribution of stiffness assumed for each elementary beam (mean and standard deviation) are updated using the stiffness values of those combinations of elementary beams giving a best solution. It is an iterative procedure where the mean value of each distribution tends towards the true stiffness in successive iterations. The level of accuracy is limited by the quantity and quality of the available measurements. Therefore, the standard deviation of the final stiffness for each beam element (once further iterations do not lead to a reduction of the error) provides an estimation of the reliability of the prediction. Here, the method is demonstrated for the characterisation of the stiffness distribution of a beam from the simulated response to a moving load. First, deflections are calculated using a finite element beam model with assumed initial stiffness properties. There will be a record of simulated responses per measurement point that cross-entropy will try to imitate by adjusting and improving estimations of stiffness in successive iterations. The results show cross-entropy can be used as a valuable tool to estimate structural parameters and it has huge scope for applications in model calibration, bridge weigh-in-motion and monitoring. Bridge & Infrastructure Research in Ireland 2010, Cork Institute of Technology, September 2010 2010-01-01T00:00:00Z http://hdl.handle.net/10197/4160 Finding the Distribution of Bridge Lifetime Load Effect by Predictive Likelihood Caprani, Colin C.; O'Brien, Eugene J. To assess the safety of an existing bridge, the loads to which it may be subject in its lifetime are required. Statistical analysis is used to extrapolate a sample of load effect values from the simulation period to the required design period. Complex statistical methods are often used and the end result is usually a single value of characteristic load effect. Such a deterministic result is at odds with the underlying stochastic nature of the problem. In this paper, predictive likelihood is shown to be a method by which the distribution of the lifetime extreme load effect may be determined. A basic application to the prediction of lifetime Gross vehicle Weight (GVW) is given. Results are also presented for some cases of bridge loading, compared to a return period approach and important differences are identified. The implications for the assessment of existing bridges are discussed. 3rd International ASRANet Colloquium, held at the University of Glasgow, 10-12 July 2006. 2006-07-01T00:00:00Z http://hdl.handle.net/10197/4159 The Determination of Site-Specific Imposed Traffic Loadings on Existing Bridges Graves, S.A.; O'Brien, Eugene J.; O'Connor, Alan The Fourth International Conference on Bridge Management 2000-01-01T00:00:00Z http://hdl.handle.net/10197/4158 Prediction of Residential BMW Generation According to Socio-Economic And Household Characteristics For The Dublin Region Purcell, M.; Magette, W. L. Despite the fact that biodegradable wastes account for 72% of the total municipal waste stream in Ireland, less than 6% of collected biodegradable wastes were recovered in 2004. Both planning and design of integrated municipal solid waste management systems require accurate prediction of solid waste generation. This paper discusses the potential household biodegradable municipal waste (BMW) generation for the Dublin Region, Ireland, using statistical data on socio-demographics, particularly household size and social class as the main variables. Historical research was used to assign BMW generation rates. A Geographical Information System (GIS) "model" of BMW generation was created using ArcMap, a component of ArcGIS 9. BMW generation was predicted within a diverse "landscape" of residential areas. The results highlight the importance of tailoring waste management strategies to small management areas. 21st International Waste Management and Landfill Symposium, Sardinia, 1-5 October 2007 2007-10-01T00:00:00Z http://hdl.handle.net/10197/4157 Nutrient and Sediment Removal by Vegetated Filter Stips Magette, W. L.; Brinsfield, Russell B.; Palmer, Robert E.; Wood, James D. A field study utilizing simulated rainfall and bare plots 5.5m wide by 22m long was conducted to study the effectiveness of vegetated filter strips 4.6 and 9.2m long in removing nutrients and sediments from agricultural runoff. Losses of N and P from plots with filters were highly variable as compared to plots with no filters. Generally, nutrient removals appeared to be greater with the longer filters, but decreased as the number of runoff events increased. Mass losses of TSS, TN and TP in surface runoff were reduced by 66%, 0% and 27%, respectively, by 4.6m (15ft) long filters. TSS, TN and TP reductions by 9.2m (30ft) long filter strips of the lengths utilized in this study were effective in removing sediment from runoff but should not be relied upon as the primary means to reduce nutrient losses from agricultural areas. 1989-03-01T00:00:00Z http://hdl.handle.net/10197/4156 Piles for offshore wind turbines: A state of the art review Gavin, Kenneth; Igoe, David; Doherty, Paul The paper considers the current state of the art for estimating the pull-out capacity of driven open-ended piles used to support wind turbine foundations founded on sand. The latest edition of the American Petroleum Institute guidelines for pile design includes a conventional earth pressure approach and four alternative cone penetration test (CPT) methods for estimating pile shaft resistance in sand. A database of open-ended pile tests was used to assess the predictive reliability of the design approaches. While the earth pressure approach was unreliable, exhibiting bias with pile slenderness and sand relative density, the CPT methods were shown to provide improved and relatively consistent estimates of pile capacity. However, the tension loads experienced by wind turbine foundations are significantly higher than those applied to piles in the database. When the CPT methods were used to estimate the pile length required to support a 5 MW turbine installed in typical offshore soil conditions, the CPT methods provided a wide range of predicted pile lengths. The reasons for this divergence are discussed and an alternative framework for considering driven pile shaft resistance is put forward. 2011-08-01T00:00:00Z http://hdl.handle.net/10197/4146 Performance of concrete incorporating GGBS in aggressive wastewater environments O’Connell, Martin; McNally, Ciaran; Richardson, Mark G. Concrete is traditionally used as the main component of wastewater facilities. The sulfate and acidic environment presents significant challenges. Supplementary cementitious materials (SCM) such as GGBS are being used in increasing quantities in concrete and have been shown to provide concrete with increased durability in this particular environment. They have traditionally been used with CEM I, but in recent years a shift in concrete practice has led to the introduction of CEM II cements with reduced CO2 footprint and obvious environmental and economic benefits. However, the change in cement chemistry associated with using CEM II and GGBS must also be accounted for in concrete specifications for aggressive environments. This has particular importance when concrete is exposed to elevated sulfate and sulfuric acid environments, such as that associated with water and wastewater treatment. The performance of CEM II/A-L cements with varying amounts of GGBS was evaluated through a series of tests conducted to determine their durability characteristics in respect of sulfate attack and sulfuric acid attack. As a benchmark, samples were also tested using CEM I cement, CEM I with GGBS, and a sulfate resistant Portland cement. Results have shown that for all cases, the addition of GGBS resulted in considerable reductions in sulfate induced expansion relative to samples using CEM I or CEM II binders alone. A slight improvement in performance relative to sulfate resisting Portland cement (SRPC) binders was also observed. However in respect of the sulfuric acid environment the regime proved too harsh and ultimately resulted in the early failure of all samples. Some difference in performance was noted, but this was not considered noteworthy. The influence of pH and acid type was studied. The conclusions were that the concretes tested cannot adequately address the durability threat to all parts of wastewater infrastructure over a significant life span due to the extraordinarily harsh nature of this form of attack. 2012-02-01T00:00:00Z http://hdl.handle.net/10197/4144 Use of weigh-in-motion (WIM) data for site-specific LRFR bridge rating Zhao, Hua; Uddin, Nasim; Waldron, Christopher J.; O'Brien, Eugene J. In this paper, truck weigh-in-motion (WIM) data are used to develop live load factors for use on Alabama state-owned bridges. The factors are calibrated using the same statistical methods that were used in the original development of AASHTO’s Load and Resistance Factor Rating (LRFR) Manual. This paper describes the jurisdictional and enforcement characteristics in the state, the WIM data filtering, sorting, and quality control, as well as the calibration process. Large WIM data sets from five sites were used in the calibration and included different truck volumes, seasonal and directional variations, and WIM data collection windows. Certain MATLAB programs were developed in the live load factor calibration process. The resulting state-specific live load factors are smaller than those of LRFR manual and are recommended to the Alabama Department of Transportation (ALDOT) in rating their bridges more efficiently 6th International Conference on Weigh-in-Motion, ICWIM6, Dallas, 4-7 June, 2012 2012-06-04T00:00:00Z http://hdl.handle.net/10197/4143 Load effect of single-lane traffic simulations on long-span bridges Lipari, Alessandro; Caprani, Colin C.; O'Brien, Eugene J. It is well acknowledged that long-span road bridges (about 50 m long and more) are governed by congestion traffic rather than free-flow conditions. A conventional model for the design of new long-span bridges is to place over the bridge a load model representing a platoon of heavy vehicle with the gaps between them reduced to a minimum. This assumption is too conservative for existing bridges, given the large disruption costs faced by their closure for rehabilitation. In order to model the close gaps between vehicles, characteristic of congested traffic, microsimulation is needed to accurately capture drivers’ behaviour. In this work, a microsimulation model is studied and found to replicate many different known forms of congestion. As a first approach to the topic, single-lane simulations of identical vehicles have been carried out in order to obtain load effect on a sample bridge. This load effect is studied with reference to the form of traffic causing the load effect. It is found that the most extreme load effect may not be caused by purely congested traffic but also by non-stationary congested conditions Bridge & Infrastructure Research in Ireland 2010, Cork Institute of Technology, 2010 2010-01-01T00:00:00Z http://hdl.handle.net/10197/4142 Statistical computation for extreme bridge traffic load effects Caprani, Colin C.; O'Brien, Eugene J. The maintenance of highway infrastructure constitutes a major expenditure in many countries. This cost can be reduced significantly by minimizing the repair or replacement of highway bridges. In the assessment of existing bridges, the strength estimate tends to be more accurate than that of traffic loading, due to the more variable nature of loading. Recent advances in the statistical analysis of highway bridge traffic loading have resulted in more accurate forecasts of the actual loading to which a bridge is subject. While these advances require extensive numerical computation, they can significantly improve the accuracy of the calculation. This paper outlines the recent advances and describes the associated computational aspects in detail Eighth International Conference on Computational Structures Technology, Las Palmas de Gran Canaria, Spain, from 12 to 15 September 2006 2006-09-12T00:00:00Z http://hdl.handle.net/10197/4141 In situ strength characterisation of peat and organic soil using full-flow penetrometers Boylan, Noel; Long, Michael (Michael M.); Mathijssen, F.A.J.M. Full-flow penetrometers have been shown to overcome problems experienced with the cone penetrometer when measuring resistance in very soft peat and organic soil, and give a much more uniform measure of resistance than the cone in fibrous peat. However, at present there is no guidance on the interpretation of strength parameters in these soils using the T-bar and ball. This paper examines the results of tests using these devices at two research sites in the Netherlands in conjunction with high-quality Sherbrooke sampling for laboratory testing. In fibrous peat, the T-bar and ball provided a more uniform measure of resistance with a lower degree of scatter than the cone. The in situ testing results have been compared with the laboratory tests to assess the range of resistance factors relating penetration resistance to the undrained shear strength (su) and have been shown to occupy a lower range of values than the cone penetrometer. However, penetration tests in these soils are likely to be influenced by partial drainage effects and this should be considered during testing and the subsequent interpretation of results. Recommendations are made for the use of full-flow penetrometers to obtain strength parameters in these soils. 2011-07-01T00:00:00Z http://hdl.handle.net/10197/4140 Water quality monitoring during the construction of the M3 motorway in Ireland Purcell, Patrick J.; Bruen, Michael; O'Sullivan, J. J.; Cocchiglia, Letizia; Kelly-Quinn, Mary The M3 motorway in Ireland was constructed between the years 2007 and 2010. The motorway crosses the River Boyne, which is a designated salmonid water under the EU Freshwater directive, and its tributaries. The paper describes the measures taken to mitigate any potential impacts which the road scheme might have had on the aquatic environment and the water quality of the Boyne watercourses before-, during- and post-construction. The success of the mitigation measures undertaken is assessed by: (a) comparing pre-construction, during-construction and post-construction water quality data, (b) comparing measured water quality with relevant standards, (c) comparing water quality data upstream and downstream of river crossings, (d) the establishment of a pilot-scale real-time water quality monitoring station at the downstream end of the works before discharge into the river Boyne. The study concluded that the measures taken have been successful in minimising the water quality impacts associated with the road scheme. 2012-06-01T00:00:00Z http://hdl.handle.net/10197/4139 Targeted intervention strategies to optimise diversion of BMW in the Dublin, Ireland region Purcell, M.; Magette, W. L. Urgent transformation is required in Ireland to divert biodegradable municipal waste (BMW) from landfill and prevent increases in overall waste generation. When BMW is optimally managed, it becomes a resource with value instead of an unwanted by-product requiring disposal. An analysis of survey responses from commercial and residential sectors for the Dublin region in previous research by the authors proved that attitudes towards and behaviour regarding municipal solid waste is spatially variable. This finding indicates that targeted intervention strategies designed for specific geographic areas should lead to improved diversion rates of BMW from landfill, a requirement of the Landfill Directive 1999/31/EC. In the research described in this paper, survey responses and GIS model predictions from previous research were the basis for goal setting, after which logic modelling and behavioural research were employed to develop site-specific waste management intervention strategies. The main strategies devised include (a) roll out of the Brown Bin (Organics) Collection and Community Workshops in Dún Laoghaire Rathdown, (b) initiation of a Community Composting Project in Dublin City (c) implementation of a Waste Promotion and Motivation Scheme in South Dublin (d) development and distribution of a Waste Booklet to promote waste reduction activities in Fingal (e) region wide distribution of a Waste Booklet to the commercial sector and (f) Greening Irish Pubs Initiative. Each of these strategies was devised after interviews with both the residential and commercial sectors to help make optimal waste management the norm for both sectors. Strategy (b), (e) and (f) are detailed in this paper. By integrating a human element into accepted waste management approaches, these strategies will make optimal waste behaviour easier to achieve. Ultimately this will help divert waste from landfill and improve waste management practice as a whole for the region. This method of devising targeted intervention strategies can be adapted for many other regions. 2011-09-01T00:00:00Z http://hdl.handle.net/10197/4138 The Development and Testing of an Instrumented Open-Ended Model Pile Igoe, David; Doherty, Paul; Gavin, Kenneth This paper describes the development of a model instrumented open-ended (pipe) pile. The importance of model geometry and separating the shaft, annular and plug load, and horizontal effective stresses is discussed. A detailed description of the construction of the twin-walled open-ended pile is presented. Particular attention was given to protecting the fragile instrumentation from the rigours of installation and the effects of water ingress. Calibration procedures, which were used to verify the instrument reliability, are also discussed. The final section describes field tests conducted in both loose sand and medium-dense sand deposits, which are used to validate the instrument performance. 2010-01-01T00:00:00Z http://hdl.handle.net/10197/4136 Web-Enabling of Architectural Heritage Inventories Morrish, Sean; Laefer, Debra F. Surveys and inventories of the built environment have improved the understanding of the state of existing heritage structures and historic districts and assisted in their preservation by thorough and consistent documentation. Unfortunately, full exploitation of these resources has been impeded by their static, non-interactive nature as printed documents (ie, reports or maps). This article presents recent attempts to improve access of such resources through their web-enablement. Specifically, issues of usability, relevance, contemporaneousness, and spatial integration are evaluated. These requirements are considered with respect to a new resource, Historic Ireland's Built Environment and Road Network Inventories Access (HIBERNIA). This integrated, extendable database and geographic information system (GIS) is featured as an example of how access to these surveys and inventories can be improved to form the basis for future developments to provide a more complete picture of heritage resources and enable innovative resource management strategies. 2009-11-09T00:00:00Z http://hdl.handle.net/10197/4134 Case study of a project-based learning course in civil engineering design Gavin, Kenneth This paper describes the use of project-based learning to teach design skills to civil engineering students at University College Dublin (UCD). The paper first considers the development of problem-based leaning (PBL) as a tool in higher education. The general issues to be considered in the design of the curriculum for a PBL module are reviewed. Consideration of the literature on the application of PBL in civil engineering suggests that, because of the hierarchical nature of engineering education, PBL is best applied in a hybrid form known as Project Based Learning. A detailed description is given of how hybrid PBL was implemented in the final year of a civil engineering degree programme. In the final section, the results of an evaluation process designed to gain an insight into students’ perceptions of the PBL process are reviewed. The module, which was developed at UCD, provided an excellent mechanism for developing many skills, including problem-solving, innovation, group-working and presentation skills desired by graduate employers. It was clear that the students enjoyed the peer to peer teaching and increased interaction with staff and external experts, which the problem-solving nature of the module facilitated. 2011-12-01T00:00:00Z http://hdl.handle.net/10197/4127 Attitudes and behaviour towards waste management in the Dublin, Ireland region Purcell, M.; Magette, W. L. The hypothesis of this research was that attitudes about the management of biodegradable municipal waste (BMW) are spatially variable, even within a city of modest (1.2 million) population. For a select number of representative electoral districts in the Dublin, Ireland region, residents were surveyed regarding attitudes towards waste management in general, and BMW management in particular. A total of 850 survey responses were collected. Door-to-door interviews produced 688 responses in the residential sector; these were supplemented by 162 responses to a web-based survey. The surveys revealed that the majority of households use local authority, rather than private, waste collection services (both are available). The majority of residents, regardless of the local authority in which they live, were satisfied with their waste management service. “Reducing the quantity of waste generated” was regarded the most important future issue for 28% of residential respondents. Statistical analyses of the survey responses showed that the local authority in which respondents resided significantly influenced most responses (including waste collection service used, waste service satisfaction and backyard composting activity). Many responses (including waste service satisfaction, waste management influences) were also significantly related to the respondents’ personal characteristics (e.g., education level, type of accommodation, age, etc.). These statistical results proved the hypothesis of the research and demonstrated that waste management initiatives designed for one area of the city (or, indeed, for uniform application to the city as a whole) could ignore the needs of other areas. The survey responses suggest that targeted intervention strategies would lead to improved diversion rates of BMW from landfill, a requirement of the Landfill Directive 1999/31/EC. 2010-10-01T00:00:00Z http://hdl.handle.net/10197/4126 Shaft Capacity of Open-Ended Piles in Clay Doherty, Paul; Gavin, Kenneth This paper describes an experimental investigation designed to assess the impact of pile end condition on the capacity of piles installed in soft clay. A series of field tests are described in which instrumented open-ended and closed-ended model piles were jacked into soft clay. The radial stresses, pore pressures, and load distribution were recorded throughout installation, equalization, and load-testing. Although the total stress and pore pressure developed during installation were related to the degree of soil plugging, the radial effective stress that controls the shaft resistance was shown to be independent of the mode of penetration. The long-term shaft capacity of the open-ended pile was closely comparable to that developed by closed-ended piles, suggesting a limited influence of end condition on the fully equalized shaft resistance. In contrast to the shaft resistance, the base capacity was highly dependent on the degree of plugging. 2011-11-01T00:00:00Z http://hdl.handle.net/10197/4125 Cyclic and Rapid Axial Load Tests on Displacement Piles in Soft Clay Doherty, Paul; Gavin, Kenneth Offshore piles are subjected to complex loading regimes, which include both rapidly applied static and cyclic loads. This note describes an experimental investigation conducted in order to assess the factors influencing the response of offshore piles to these loading conditions. The tests were performed using instrumented model piles installed in soft clay. During cyclic loading, the piles demonstrated a transition from stable to unstable behaviour when the applied loads reached a specific load threshold. Stable behaviour was defined when increments of plastic displacement decreased as the number of load cycles increased. During stable behaviour, radial effective stresses at the pile-soil interface remained constant. During unstable behaviour, pore pressures at the pile-soil interface rose as the number of cycles increased. This resulted in reduced radial effective stresses and progressively increasing displacement rates. Due to the presence of these excess pore pressures, the shaft resistance recorded during static load tests, performed after a period of unstable cyclic loading, were lower than those measured on piles where the pore pressure was fully equalised. However, the axial resistance was seen to be rate dependent. Fast loading of the pile resulted in reductions of pore water pressure at the soil-pile interface and enhanced shaft resistance which could overcome the negative effect caused by cyclic loading. 2012-08-01T00:00:00Z http://hdl.handle.net/10197/4124 Undergraduate Research Models Applicable for Geotechnics Laefer, Debra F. The projected, increasing gap between expected workforce staffing needs of those with science technology and engineering (STEM) training and the anticipated graduates with STEM degrees demands a re-examination of how to increase the number of STEM students graduating and remaining in STEM careers. Given the continued acute under-representation of women and some racial minorities, these groups warrant additional consideration, as their further engagement may help fill the shortfall. In debates and research surrounding these challenges, the issue of retention has received relatively little investigation both in terms of bachelor's level retention for degree completion and longer-term retention within STEM activities (either educational or industrial). Anecdotal information would indicate that undergraduate students engaged in research are more likely to complete their degrees, improve their grades after participation, enroll in STEM-based master's programs, and remain in STEM careers. This paper outlines various models for undergraduate engagement in geotechnical research, as a means to develop curricular and non-curricular, short- to medium-term opportunities to promote such efforts. Geo-Frontiers Congress 2011, Dallas, Texas, United States, March 13-16, 2011 2011-03-13T00:00:00Z http://hdl.handle.net/10197/4123 Monitoring Bridge Dynamic Behaviour Using an Instrumented Two Axle Vehicle McGetrick, P.; González, Arturo; O'Brien, Eugene J. Highway structures such as bridges are subject to continuous degradation primarily due to ageing, loading and environmental factors. A rational transport policy must monitor and provide adequate maintenance to this infrastructure to guarantee the required levels of transport service and safety. Increasingly in recent years, bridges are being instrumented and monitored on an ongoing basis due to the implementation of Bridge Management Systems. This is very effective and provides a high level of protection to the public and early warning if the bridge becomes unsafe. However, the process can be expensive and time consuming, requiring the installation of sensors and data acquisition electronics on the bridge. This paper investigates the use of an instrumented 2-axle vehicle fitted with accelerometers to monitor the dynamic behaviour of a bridge network in a simple and cost-effective manner. A simplified half car-beam interaction model is used to simulate the passage of a vehicle over a bridge. This investigation involves the frequency domain analysis of the axle accelerations as the vehicle crosses the bridge. The spectrum of the acceleration record contains noise, vehicle, bridge and road frequency components. Therefore, the bridge dynamic behaviour is monitored in simulations for both smooth and rough road surfaces. The vehicle mass and axle spacing are varied in simulations along with bridge structural damping in order to analyse the sensitivity of the vehicle accelerations to a change in bridge properties. These vehicle accelerations can be obtained for different periods of time and serve as a useful tool to monitor the variation of bridge frequency and damping with time. Bridge & Infrastructure Research in Ireland 2010 (BRI 10), Cork, 2-3 September 2010 2010-09-02T00:00:00Z http://hdl.handle.net/10197/4122 Detection of Bridge Dynamic Parameters Using an Instrumented Vehicle González, Arturo; O'Brien, Eugene J.; McGetrick, P. Highway structures such as bridges are subject to continuous degradation primarily due to ageing and environmental factors. A rational transport policy requires the monitoring of this transport infrastructure to provide adequate maintenance and guarantee the required levels of transport service and safety. In Europe, this is now a legal requirement - a European Directive requires all member states of the European Union to implement a Bridge Management System. However, the process is expensive, requiring the installation of sensing equipment and data acquisition electronics on the bridge. This paper investigates the use of an instrumented vehicle fitted with accelerometers on its axles to monitor the dynamic behaviour of bridges as an indicator of its structural condition. This approach eliminates the need for any on-site installation of measurement equipment. A simplified half-car vehicle-bridge interaction model is used in theoretical simulations to test the possibility of extracting the dynamic parameters of the bridge from the spectra of vehicle accelerations. The effect of vehicle speed, vehicle mass and bridge span length on the detection of the bridge dynamic parameters are investigated. The algorithm is highly sensitive to the condition of the road profile and simulations are carried out for both smooth and rough profiles. 5th World Conference on Structural Control and Monitoring, 12th-14th July, Tokyo, Japan 2010-01-01T00:00:00Z http://hdl.handle.net/10197/4121 A Systematic Approach for Large-scale, Rapid, Dilapidation Surveys of Historic, Masonry Buildings Clarke, Julie; Laefer, Debra F. Dilapidation surveys may require extensive resources to achieve detailed accounts of damage for intervention purposes or may involve only limited resources but be restricted to an extremely rapid assessment (e.g. post-earthquake, life-safety inspection). Neither provides a holistic, cost-effective approach for evaluating the general health of a large number of structures, as is needed for urban planning, historic designation determination, and risk assessment due to adjacent works. To overcome this limitation, index images are introduced for a systematic approach for rapidly conducting large-scale, dilapidation surveys of historic masonry buildings. This method, the University College Dublin Inspection Method (UCDIM), is tested against both a detailed inspection and an alternative rapid approach to determine accuracy and resource intensiveness through its application by three inspectors of various levels of experience to six buildings in the city centre of Dublin, Ireland. The UCDIM provided a damage ranking of ρ = 0.94 for all inspectors, regardless of experience, except when painted or rendered façades were included. The UCDIM, when compared to detailed inspection provided a high level of reliability, cost savings of approximately 90% and several months of time savings since interior access was not required. 2012-05-16T00:00:00Z http://hdl.handle.net/10197/4120 An investigation of correlation factors linking footing resistance on sand with cone penetration test results Gavin, Kenneth; Tolooiyan, Ali Significant research effort has led to improvements in our ability to estimate the ultimate bearing resistance of footings in sand. These techniques often estimate the footing resistance at relatively large displacements, typically 10% of the footing width, qb0.1. Cone Penetration Test (CPT) design methods typically link qb0.1 and qc through a constant reduction factor, a. A range of a factors for shallow footings have been proposed, some methods suggest that a is constant and while others that it varies with footing width and depth (or stress level). There is a dearth of field data with which to compare these correlation factors, in particular where foundation width and depth have been varied in the same ground conditions. For this reason finite element analyses have proven to be a useful tool for performing the parametric studies required to asses factors controlling a. This paper describes the results of numerical analyses performed to investigate a factors for soil profiles which were calibrated using the results of the CPT tests performed at a dense sand test-bed site. The numerical model was first used to perform parametric 2 analyses to consider the effect of footing width, B and footing depth, D on the a factor mobilised in dense Blessington sand. In order to assess the effects of relative density, footing tests in a range of natural sands with variable in-situ densities were modeled. The results of the finite element analyses suggest that a direct correlation between qb0.1 and qc can be established at a given test site which is independent of footing width and depth and is relatively weakly dependent on the sands relative density if the zone of influence of the foundation considered is large enough. 2012-11-01T00:00:00Z http://hdl.handle.net/10197/4119 Estimation of lifetime maximum distributions of bridge traffic load effects O'Brien, Eugene J.; Hajializadeh, Donya; Sheils, Emma; Enright, Bernard This paper considers the problem of assessing traffic loading on road bridges. A database of European WIM data is used to determine accurate annual maximum distributions of load effect. These in turn are used to find the probability of failure for a number of load effects. Using the probability of failure as the benchmark, traditional measures of safety – factor of safety and reliability index – are reviewed. Both are found to give inconsistent results, i.e., a given factor of safety or reliability index actually corresponds to a range of different probabilities of failure The Sixth International IABMAS Conference on Bridge Maintenance, Safety, Management, Resilience & Sustainability, Stresa, Lake Maggiore, Italy, 8-12 July 2012 2012-07-08T00:00:00Z http://hdl.handle.net/10197/4118 Interpreting critical thinking for engineering education - the views of employers and academics Ahern, Aoife; O'Connor, Tom; Mac Ruairc, Gerry; McNamara, Martin Third level educators are increasingly being called on to clarify the nature of the education they provide and the contribution of their graduates to society. There is therefore considerable interest in the generic attributes of graduates (Jones 2009), and how educational institutions can describe the quality of their graduates in ways that are meaningful to a wide range of stakeholders, including employers, professional groups and policy makers (Barrie 2006). Critical thinking is considered by some to be the primary graduate attribute yet difficulties remain in arriving at precise definitions of the concept and how it is theorised for educational practice. This paper addresses this issue and offers a theoretical framework for critical thinking as it applies to engineering education. The paper will describe: a series of interviews and documentary analysis of course work and course descriptors in the university that examine the perspective of academics from various disciplines and students of critical thinking. Together these data have been used with Karl Maton’s Legitimation Code Theory to develop a model of critical thinking. Also described are plans for a series of interviews which draws upon the views of employers in engineering regarding the employability of university graduates and the importance of critical thinking as an attribute for newly qualified engineers. A key finding is that critical thinking, rather than being a static attribute which is at the pinnacle of student attainment, is a dynamic concept which requires educators to guide their students through cycles of engagement with grounded descriptive knowledge and knowledge which is abstract and obtuse. ICEE : An International Conference on Engineering Education : 21-26 August 2011 : Belfast, Northern Ireland, UK 2011-08-01T00:00:00Z http://hdl.handle.net/10197/4117 Mechanical behaviour and 3D stress analysis of multi-layered wooden beams made with welded-through wood dowels O'Loinsigh, Cian; Oudjene, M.; Shotton, Elizabeth; Pizzi, A.; Fanning, Paul This paper presents experimental and numerical investigations on multi-layered timber beams using welded-through wood dowels in place of traditional poly(vinyl acetate) (PVAc)-adhesives (or metallic nails). Four-layer beams were constructed with varying numbers of dowels, in each, and then loaded using four-points bending tests to evaluate the mechanical performance of these beams. The practical difficulties encountered in constructing deeper multi-layer beams are discussed and possible solutions which have been employed for the purpose of this work, and proved successful are presented. In order to investigate thoroughly the full potential of multi-layered beams with a very limited number of experimental studies, a 3D FE model has been presented, validated against experimental results and then used to study some influential parameters. The results showed that a reasonable bending stiffness of multi-layered beams is achievable with a good combination of material and geometric parameters. 2012-01-01T00:00:00Z http://hdl.handle.net/10197/4116 Stage–discharge prediction in straight compound channels using 3D numerical models Conway, Philip; O'Sullivan, J. J.; Lambert, M. F. An improved approach for applying three-dimensional (3D) computational fluid dynamics (CFD) models to estimate uniform flow stage–discharge relationships and velocity distributions in straight compound channels is presented. Commonly used modelling approaches tend to be over-specified. For a given flow and water level, desired results are obtained through calibration of resistance coefficients that can be artificially high and vary with changing flow conditions. Furthermore, the momentum interaction at the main channel–floodplain interface is sometimes ignored or is accounted for using a constant eddy viscosity. This potentially results in an overestimation of conveyance capacity in compound channels. The proposed approach represents an advance on these methods and uses a 3D CFD model with k– turbulence closure in a predictive capacity where a flow together with physically realistic resistance coefficients are specified. Downstream water levels are then iteratively adjusted until uniform flow conditions are established in the channel. The approach is validated against benchmark experimental data obtained from the largescale UK Flood Channel Facility and is compared with predictions from divided channel methods. 2012-06-01T00:00:00Z http://hdl.handle.net/10197/4115 Characterization of household and commercial BMW generation according to socio-economic and other factors for the Dublin Region Purcell, M.; Magette, W. L. Both planning and design of integrated municipal solid waste management systems require accurate prediction of solid waste generation. This research predicted the quantity and distribution of Biodegradable Municipal Waste (BMW) generation for the Dublin (Ireland) region. Socio-economic variables, housing types, and the sizes and main activities of commercial establishments were hypothesized as the key determinants contributing to the spatial variability of BMW generation. A Geographical Information System (GIS) „model‟ of BMW generation was created using ArcMap, a component of ArcGIS 9. Statistical data including socio-economic status and household size were mapped on an electoral district basis. Historical research was used to assign BMW generation rates to residential and commercial establishments. These predictions were combined to give overall BMW estimates for the region. The GIS facilitates the visual and spatial distribution of BMW to be assessed within the region. BMW generation was predicted within a diverse „landscape‟ of residential areas, as well as from a variety of commercial establishments (restaurants, hotels, hospitals etc). By changing the input data, this estimation tool can be adapted for use in other Irish cities. International Conference on Solid Waste Technology and Management, Philadelphia, USA, 18-21 March 2007 2007-03-18T00:00:00Z http://hdl.handle.net/10197/4112 The Influence of Statistical Spatial Repeatabiliy on Remaining Pavement Life O'Brien, Eugene J.; Taheri, A. A road develops permanent deformation and fatigue damage because of the strains induced in its structure by surface loading and environmental change. A mechanistic-empirical approach is implemented here to simulate the deterioration of a pavement. A quarter car model is used to simulate pavement/vehicle dynamic interaction and a feedback mechanism is implemented after each run to update the pavement profile after the passage of each axle. In this way, the influence of Statistical Spatial Repeatability (SSR) is incorporated into the pavement damage model. The model is run for two sample profiles. The first is a simple step profile which demonstrates that the patterns of damage relate to the two natural frequencies of the quarter car. An initially random profile is also investigated. A complete history of the surface profile during its life demonstrates how the peaks and troughs migrate in response to the evolving pattern of SSR. 6th International Conference on Computational Stochastic Mechanics (CSM-6), Rhodos, Greece, June 13-16, 2010 2010-08-01T00:00:00Z http://hdl.handle.net/10197/4111 Enhancing flood resilience through improved risk communications O'Sullivan, J. J.; Bradford, R. A.; Bonaiuto, M.; De Dominicis, S.; Rotko, P.; Aaltonen, J.; Waylen, K.; Langan, S. J. A framework of guiding recommendations for effective pre-flood and flood warning communications derived from the URFlood project (2nd ERA-Net CRUE Research Funding Initiative) from extensive quantitative and qualitative research in Finland, Ireland, Italy and Scotland is presented. Eleven case studies in fluvial, pluvial, coastal, residual and “new” flood risk locations were undertaken. The recommendations were developed from questionnaire surveys by exploring statistical correlations of actions and understandings of individuals in flood risk situations to low, moderate and high resilience groupings. Groupings were based on a conceptual relationship of self-assessed levels of awareness, preparedness and worry. Focus groups and structured interviews were used to discuss barriers in flood communications, explore implementation of the recommendations and to rank the recommendations in order of perceived importance. Results indicate that the information deficit model for flood communications that relies on the provision of more and better information to mitigate risk in flood-prone areas is insufficient, and that the communications process is very much multi-dimensional. The recommendations are aimed at addressing this complexity and their careful implementation is likely to improve the penetration of flood communications. The recommendations are applicable to other risks and are transferrable to jurisdictions beyond the project countries. 2012-07-20T00:00:00Z http://hdl.handle.net/10197/4110 Quantitative Support for a Qualitative Foundation Reuse Assessment Tool Laefer, Debra F. This paper provides a quantification of the inputs for an existing qualitative foundation project planning model, namely ARUP’s Sustainable Project Appraisal Routine (SPeAR) diagram. The goal is to provide an improved mechanism for designers to communicate with clients about the potential benefits of foundation reuse from a planning and environmental perspective for an individual project or group of projects based on the relative value of eight factors: (1) Site Location on Previously Developed Land; (2) Archeology and Historical Constraints; (3) Geological Conditions and Constraints; (4) Sustainability and Materials Reuse; (5) Land Value and Cash Flow Projections; (6) Construction Costs; (7) Consistency in Building Location; and (8) Approvals and Development Risk. For each category a six-point scale is provided that can be fully adopted in any community worldwide to evaluate the absolute and relative benefits between sites, even between disparate cities or countries. An example of the implementation of this modified SPeAR model is provided for a citycenter location in Dublin, Ireland. Geo-Frontiers Congress 2011, Dallas, Texas, United States, March 13-16, 2011 2011-01-01T00:00:00Z http://hdl.handle.net/10197/4109 Identifying critical source areas for phosphorus loss in Ireland using field and catchment scale ranking schemes Hughes, K.J.; Magette, W. L.; Kurz, I. Phosphorus (P) in agricultural runoff is a major pollutant in many of Ireland's surface waters. Identification of areas that are at a high risk for P loss to surface waters is a critical component of river basin management. Two P ranking schemes (PRS's) were developed for Ireland, based on multi-criteria analysis approaches proposed in both the US and Europe, to predict the relative likelihood of P loss at both the field and catchment scales. The Field PRS was evaluated by comparing predicted rankings of potential P loss and transport against measured edge-of-field Dissolved Reactive P (DRP) loss for three fields with varying soil P levels. Qualitatively, results indicated that the Field PRS rankings corresponded to the magnitudes of measured P loss for the field sites, as well as to a reasoned evaluation of the relative likelihood that the fields would lose P that would subsequently make its way to surface water. The Catchment PRS was evaluated on a total of 31 catchments and sub-catchments by comparing predicted rankings of potential P loss and transport against measured in-stream median Molybdate Reactive P (MRP). Rankings of the relative likelihood of P loss and transport predicted by the Catchment PRS were positively correlated with median in-stream MRP (r=0.51, P<0.05). Although the data available for these evaluations were limited, especially at field scale, and further research may identify the opportunity for modifications, both field and catchment scale P ranking schemes demonstrated a potential for identifying critical P source areas within catchments dominated by grass-based agricultural production systems, such as those in Ireland. 2005-03-01T00:00:00Z http://hdl.handle.net/10197/4108 WAVE - A European Research Project on Weigh-in-Motion Jacob, Bernard; O'Brien, Eugene J. WAVE (Weigh-in-motion of Axles and Vehicles for Europe) is a research project, part-funded by the European Commission, with the objective of improving the accuracy and performance of Weigh-in-Motion (WIM) technology. It has a budget of the order of $ 2 million and will run from mid 1996 to mid 1998. It has close links and a substantial overlap of membership with COST323, a pan-European group with representatives from about 20 countries which coordinates nationally funded activities relating to WIM. The principal objectives of WAVE are: (i) to improve the accuracy of WIM systems, (ii) to develop a prototype pan-European WIM database, (iii) to develop calibration and testing procedures for WIM system performance and accuracy, particularly for cold climates and (iv) to develop a prototype fibre optic WIM sensor National Traffic Data Acquisition Conference (NATDAQ '96), Albuquerque, New Mexico, 1996 1996-05-05T00:00:00Z http://hdl.handle.net/10197/4107 Recent Advances in the Governing Form of Traffic for Bridge Loading Caprani, Colin C.; O'Brien, Eugene J. The assessment of site-specific bridge traffic loading using WIM data is a critical feature of minimizing the cost of rehabilitation and replacement for bridge stock. For short- to medium-span bridges, it is often assumed that free-flowing traffic, including the dynamic interaction between the vehicles and bridge, governs the extreme load effect. In this paper, some recent advances in statistical techniques applied to bridge load effect extrapolation are presented. A critical review of these new approaches is made and it is shown that extrapolation results are now considerably more reliable and repeatable. It is also shown that there is doubt over the governing form of traffic. Therefore, the authors present some initial results of congested-traffic models in comparison to a free-flowing model. For a range of bridge lengths and load effects, the authors determine the dynamic ratio that would be required for free-flowing traffic to govern. The implications of these recent advances and various findings are discussed with reference to the future direction of research into bridge traffic loading International workshop "Civil Structural Health Monitoring 2", WIM (Weigh In Motion), Load capacity and bridge performance In the Context of Risk Assessment, Maintenance and Life Cost Based Design, September 28 - October 1, 2008 - Taormina - Sicily (Italy) 2010-01-01T00:00:00Z http://hdl.handle.net/10197/4106 Probability-based assessment of the durability characteristics of concretes manufactured using CEM II and GGBS binders McNally, Ciaran; Sheils, Emma This paper presents an overview of an investigation into the durability characteristics of blends of GGBS with CEM II/A Portland cements. The introduction of the Emission Trading Scheme has focussed attention on the carbon footprint arising from concrete construction, leading to many countries employing cementitious binder combinations not previously used. In Ireland for example concrete practice has recently changed to allow the addition of GGBS to CEM II/A cements at the concrete mixer, dependent on these blends providing adequate durability. To demonstrate this performance, specific research was conducted into the influence of GGBS addition on resistance to chloride ingress and carbonation, as well as compressive strength. The data from the testing was then used as input parameters for a number of probabilistic models describing chloride and carbonation related deterioration mechanisms. The influence of GGBS content on the expected service life is determined and compared to other research in this area 2012-05-01T00:00:00Z http://hdl.handle.net/10197/4101 Design of the curriculum for a second-cycle course in civil engineering in the context of the Bologna framework Gavin, Kenneth This paper describes the design of the curriculum for a Master of Engineering programme in civil engineering at University College Dublin. The revised programme was established to meet the requirements of the Bologna process and this paper specifically considers the design of a new, second-cycle master's component of the programme. In addition to considering the content required to meet the learning outcome specified by the professional accreditation body, the paper presents details of attempts to move from a traditional instructor-centred model to a student-centred model of education in order to promote reflective (deep) learning. Although the paper presents a model curriculum for a civil engineering programme, the holistic approach to curriculum design outlined, which considers the organisation, sequence and evaluation strategies adopted, is applicable to all subject areas in higher education 2010-02-17T00:00:00Z http://hdl.handle.net/10197/4100 Using instrumented vehicles to detect damage in bridges Keenahan, Jennifer; McGetrick, P.; O'Brien, Eugene J.; González, Arturo Bridge structures are subject to continuous degradation due to the environment, ageing and excess loading. Monitoring of bridges is a key part of any maintenance strategy as it can give early warning if a bridge is becoming unsafe. This paper will theoretically assess the ability of a vehicle fitted with accelerometers on its axles to detect changes in damping of bridges, which may be the result of damage. Two vehicle models are used in this investigation. The first is a two degree-of-freedom quarter-car and the second is a four degree-of-freedom halfcar. The bridge is modelled as a simply supported beam and the interaction between the vehicle and the bridge is a coupled dynamic interaction algorithm. Both smooth and rough road profiles are used in the simulation and results indicate that changes in bridge damping can be detected by the vehicle models for a range of vehicle velocities and bridge spans. 15th International Conference on Experimental Mechanics, Porto, Portugal, 22-27 July 2012, Paper No. 2934 2012-07-22T00:00:00Z http://hdl.handle.net/10197/4099 Flow resistance of emergent vegetation James, C. S.; Birkhead, A. L.; Jordanova, A. A.; O'Sullivan, J. J. Conventional resistance equations (such as those of Manning, Chézy and Darcy-Weisbach) are inappropriate for flow through emergent vegetation, where resistance is exerted primarily by stem drag throughout the flow depth rather than by shear stress at the bed. An alternative equation form is suggested, in which the resistance coefficient is related to measurable vegetation characteristics and can incorporate bed roughness when this is significant. Equation performance is confirmed by comparison of predicted and measured stage-discharge relationships for flow through artificial cylindrical stems, and by comparison of calibrated and measured drag coefficient values for natural vegetation. 2004-01-01T00:00:00Z http://hdl.handle.net/10197/4098 Modelling the Cone Penetration Test in sand using Cavity Expansion and Arbitrary Lagrangian Eulerian Finite Element Methods Tolooiyan, Ali; Gavin, Kenneth The paper considers two techniques to model the Cone Penetration Test (CPT) end resistance, qc in a dense sand deposit using commercial finite element programmes. In the first approach, Plaxis was used to perform spherical cavity expansion analyses at multiple depths. Two soil models, namely; the Mohr–Coulomb (MC) and Hardening Soil (HS) models were utilized. When calibrated using simple laboratory element tests, the HS model was found to provide good estimates of qc. However, at shallow depths, where the over-consolidation ratio of the sand was highest, the relatively large horizontal stresses developed prevented the full development of the failure zone resulting in under-estimation of the qc value. The second approach involved direct simulation of cone penetration using a large-strain analysis implemented in Abaqus/Explicit. The Arbitrary Lagrangian Eulerian (ALE) technique was used to prevent excessive mesh deformation. Although the Druker–Prager soil model used was not as sophisticated as the HS model, excellent agreement was achieved between the predicted and measured qc profiles. 2011-06-01T00:00:00Z http://hdl.handle.net/10197/4096 Dynamic Amplification Factors for Bridges with Various Boundary Conditions Carey, Ciaran; O'Brien, Eugene J.; González, Arturo It is important that the assessment of bridges be as accurate as possible. Dynamic amplification is one area in which the codes are sometimes overly conservative. Bridge dynamics is well researched but the majority of this research has concentrated on simply supported bridges. This paper examines the effect that introducing support rotational restraint has on bridge dynamic amplification factors. Finite element models are used with rotational springs at the bridge supports. This paper examines the effect of vehicle velocity on the dynamic amplification for the different end restraints. Bridge & Infrastructure Research in Ireland 2010, Cork Institute of Technology, September, 2010 2010-09-01T00:00:00Z