Thesis Cork Institute of Technology, 2019.

Aging 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 years service life for all structures. A benchmarking comparison with reported international practice has confirmed the applicability of the developed methodology - (author's abstract)