A Bridge Rehabilitation Strategy Based on the Analysis of a Dataset of Bridge Inspections in Co. Cork
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Munster Technological University SWORD - South West Open Research Deposit Masters Engineering 1-1-2019 A Bridge Rehabilitation Strategy Based on the Analysis of a Dataset of Bridge Inspections in Co. Cork Liam Dromey Cork Institute of Technology Follow this and additional works at: https://sword.cit.ie/engmas Part of the Civil Engineering Commons, and the Structural Engineering Commons Recommended Citation Dromey, Liam, "A Bridge Rehabilitation Strategy Based on the Analysis of a Dataset of Bridge Inspections in Co. Cork" (2019). Masters [online]. Available at: https://sword.cit.ie/engmas/3 This Thesis is brought to you for free and open access by the Engineering at SWORD - South West Open Research Deposit. It has been accepted for inclusion in Masters by an authorized administrator of SWORD - South West Open Research Deposit. For more information, please contact [email protected]. Department of Civil, Structural and Environmental Engineering A Bridge Rehabilitation Strategy based on the Analysis of a Dataset of Bridge Inspections in Co. Cork. Liam Dromey Supervisors: Kieran Ruane John Justin Murphy Brian O’Rourke __________________________________________________________________________________ Abstract A Bridge Rehabilitation Strategy based on the Analysis of a Dataset of Bridge Inspections in Co. Cork. Ageing highway structures present a challenge throughout the developed world. The introduction of bridge management systems (BMS) allows bridge owners to assess the condition of their bridge stock and formulate bridge rehabilitation strategies under the constraints of limited budgets and resources. This research presents a decision-support system for bridge owners in the selection of the best strategy for bridge rehabilitation on a highway network. The basis of the research is an available dataset of 1,367 bridge inspection records for County Cork that has been prepared to the Eirspan BMS inspection standard and which includes bridge structure condition ratings and rehabilitation costs. There has been no previous research on a regional Irish bridge stock of this magnitude. Research objectives are the consolidation of the dataset into a usable format, the review of previous research and the formulation of a methodology for the development of a network wide bridge rehabilitation strategy model. A procedure proposed by previous research on the prioritisation of theoretical bridge rehabilitation projects on the Chilean road network has been built upon. Statistical analysis of both recent rehabilitation projects in County Cork and of a survey of experts has led to the formulation of rehabilitation project prioritisation indices. The application of these derived indices allows the forecasting and calculation of funding requirements for network wide improvements. A review of the functional life expectancies of bridges has been undertaken. A deterioration rate which predicts the annual disimprovement in condition rating of each bridge has been calculated using statistical regression analysis and provides a basis for the estimation of investment requirements for an overarching rehabilitation strategy. An economic assessment of four rehabilitation intervention strategies has been undertaken using the Net Present Worth method. A system performance method developed in this research and which uses efficiency and effectiveness indicators taken from UK, New Zealand and French practice has determined that the range of annual investment amounts equivalent to 0.27% and 1% respectively of the bridge stock replacement cost are required to achieve full bridge network rehabilitation and provide a minimum 85 year service life for all structures. A benchmarking comparison with reported international practice has confirmed the applicability of the developed methodology. __________________________________________________________________________________ Acknowledgements I would like to sincerely thank all those who supported and assisted me during the course of my research. Firstly, I would like to thank my supervisors, Mr. Kieran Ruane, Mr. John Justin Murphy and Mr. Brian O'Rourke of the Department of Civil, Structural and Environmental Engineering, for their encouragement and guidance throughout the development and preparation of this thesis. This research was part funded by a grant from Transport Infrastructure Ireland (TII). This support is gratefully acknowledged. I would like to thank Cork County Council for granting access to the Eirspan data used in this research. I am appreciative of colleagues who assisted me by taking part in the survey of experts, the results of which were fundamental to this work. I wish to thank Dr. Seán Lacey of the Department of Mathematics for his assistance with the statistical methods used in this study. Finally, I would like to thank my family for their continued support and patience during this process. __________________________________________________________________________________ Table of Contents 1.0 Introduction. ......................................................................................................................... 1 1.1 Research aim and objectives. ............................................................................................... 2 2.0 Literature review. ................................................................................................................. 3 2.1 Bridge management systems. ............................................................................................... 3 2.2 Bridge management systems and the development of rehabilitation strategies. ................. 6 2.2.1 Bridge management system database. ....................................................................... 7 2.2.2 Bridge deterioration. .................................................................................................. 7 2.2.3 Prioritisation of rehabilitation projects. ................................................................... 10 2.3 Bridge rehabilitation strategy performance model. ........................................................... 12 2.4 Bridge management system data as a research field and gaps in existing knowledge. ..... 16 3.0 Outline of research methodology. ...................................................................................... 19 4.0 Data analysis and statistical methods. ................................................................................ 23 5.0 Bridges in the study dataset. ............................................................................................. 37 5.1 Characteristics of the study area. ....................................................................................... 37 5.2 Eirspan bridge management system. .................................................................................. 43 5.3 Dataset consolidation. ........................................................................................................ 45 5.4 Descriptive statistical analyses of the dataset. .................................................................. 46 5.5 Bridge scour as a deterioration mechanism in the study dataset. ..................................... 55 5.6 Rehabilitation cost and estimated asset value of bridge stock. ......................................... 56 5.7 Comparison with the bridge stock on national roads. ....................................................... 58 5.8 Recent bridge rehabilitation projects in the study area. .................................................... 60 6.0 Deterioration model for bridge structures. ......................................................................... 66 7.0 Prioritisation model for bridge rehabilitation projects. ...................................................... 71 7.1 Previous research. .............................................................................................................. 71 __________________________________________________________________________________ 7.2 Proposed methodology for the formulation of a prioritisation index. ............................... 72 7.2.1 Identification of influencing factors based on a survey of experts. ......................... 72 7.2.2 Prioritisation index for the rehabilitation of critical condition bridges. ................. 75 7.2.3 Prioritisation index for rehabilitation of non-critical condition bridges. ................. 81 7.2.4 Overall bridge stock prioritisation indices. .................................................................... 86 8.0 Performance model for bridge rehabilitation strategies. .................................................... 87 9.0 Development and testing of strategies. .............................................................................. 91 10.0 Discussion, conclusions and recommendations for further work. ................................. 112 References Appendix A Civil Engineering Research in Ireland (CERI) paper, Galway, August 2016 CERI paper, Dublin, August 2018 Appendix B Typical Eirspan Principal Inspection Report Appendix C List of bridges in the study dataset Appendix D Bridge stock condition index, rehabilitation cost and net present value calculations Appendix E Survey questionnaire __________________________________________________________________________________ 1.0 Introduction. Highway bridges experience deterioration due to natural hazards, ageing, and increased structural performance demands. In a climate of scarce financial resources, managers of highway bridges face challenges in maintaining a safe