Civil. Eng. And Env. Syst., 2003, Vol. 00, pp. 1–25 A DECISION-SUPPORT METHODOLOGY FOR PERFORMANCE-BASED ASSET MANAGEMENT JIM W. HALL a, *, JASON W. LE MASURIER b , EMMA A. BAKER-LANGMAN c , JOHN P. DAVIS d and COLIN A. TAYLOR d a Department of Civil Engineering, University of Bristol, Queen’s Building, University Walk, Bristol BS8 1TR, UK; b Department of Civil Engineering, University of Canterbury, Christchurch, New Zealand; c Faber Maunsell, UK; d Department of Civil Engineering, University of Bristol, UK (Received) Q1 A software-supported methodology for managing the performance of complex infrastructure systems is described. The infrastructure system is represented hierarchically, so that high level business decisions and more detailed operational decisions can be supported by the same methodology. Performance of each sub-system is captured by a set of Performance Indicators held in a database. Evidence of performance is assembled from all available sources, ranging from monitoring measurements and inspection records, design calculations and model studies to expert judgements, analogous cases and accounts of past failures. These Performance Indicators are projected through value functions reflecting organisational objectives and regulatory standards and are merged to generate a Figure of Merit for the system and each sub-system. Uncertainty in the available evidence is represented and propagated through the evidence hierarchy using Interval Probability Theory, providing a commentary on sources and implications of uncertainty in the decision. A case study of a hydro-electric reservoir system demonstrates how the approach can be used to provide a coherent overview of system performance and support asset management decision-making. Keywords: Please Q2 supply 1 INTRODUCTION The aim of the research described in this paper has been to develop new decision support techniques to enable performance-based management of complex civil engineering infra- structure systems. The work has focussed upon a group of economically important and safety–critical infrastructure systems, including dams, flood and coast defences and engi- neered and natural slopes, which have following characteristics:  The physical failure mechanisms are complex and site-specific. Available models of the failure mechanism have significant deficiencies.  The structural behaviour is spatially and temporally varied. This is often associated with natural variability in loading regime (wind, wave, rainfall, seismic) and geotechnical conditions. * Corresponding author. Tel.: þ44 117 928 9763; Fax: þ44 117 928 7783; E-mail: jim.hall@bristol.ac.uk ISSN 1028-6608 print; ISSN 1029-0249 online # 2003 Taylor & Francis Ltd DOI: 10.1080=1028660031000135086 Techset Composition Ltd, Salisbury Doc: h:/Gandb/Gcee/031008/GCEE031008.3d ManuNo.0000 Printed: 20/5/03 Page#: 25 page(s) Opp: Task: 3B2 Version:7.51f/W (Mar 4 2002)||TechRef:9.01/H (March 20 1997)