http://ktisis.cut.ac.cy/handle/10488/4779 Search the Channel search http://ktisis.cut.ac.cy/simple-search http://ktisis.cut.ac.cy/handle/10488/7559 Title: Developments in structural system reliability assessments of fixed steel offshore platforms<br/><br/>Authors: Onoufriou, Toula; Forbes, V.J<br/><br/>Abstract: In recent years there have been significant developments in the area of system reliability assessments which are becoming increasingly important given the framework of the ‘goal setting’ regime and other changes that are taking place within the offshore industry. The objective of this paper is to review and critically examine recent developments in system reliability methods for fixed steel offshore platforms specifically and identify areas that need to be examined further to maximise the benefits from the use of these techniques.The paper examines the range of proposed methods for system reliability assessment of fixed steel offshore structures under extreme environmental loading. The associated characteristics of the various methods are examined and the paper concentrates in particular on the treatment of the resistance. The various system effects including both deterministic and probabilistic effects and their relative contribution to the overall system reliability are addressed. Key issues such as the modelling uncertainties and sensitivities, validation and benchmarking of the proposed methods are also examined. The study also highlights a number of technical and philosophical issues which need to be addressed to increase the benefits from system reliability applications in design and re-assessment of fixed platforms. Sun, 29 Oct 2000 22:58:59 GMT http://ktisis.cut.ac.cy/handle/10488/7360 Title: Comparison of bridge mamagememt strategies using life-cycle cost analysis<br/><br/>Authors: Onoufriou, Toula; Rafiq, M.I.; Chryssanthopoulos, M.<br/><br/>Abstract: A comparison of safety characteristics and life-cycle costs for different bridge management strategies is presented in this paper. These strategies are based on regular inspections; on predictive models updated through regular inspections; and on predictive models updated through the use of permanent health monitoring systems. The results for these management strategies for various inspections and health monitoring outputs are presented and discussed. It is concluded that the life cycle costs of concrete structures are strongly influenced by the timings of repairs, and can be reduced considerably by delaying the repairs due to an increase in confidence of predicted performance through inspections and health monitoring data. Furthermore, it is shown that the decisions supported by permanent monitoring systems can result in significant savings whilst maintaining a target safety level of the structures. Fri, 29 Oct 2004 22:58:59 GMT http://ktisis.cut.ac.cy/handle/10488/7356 Title: Application of risk and reliability to the management of bridges<br/><br/>Authors: Onoufriou, Toula; Pardi, L.; Shetty, N.<br/><br/>Abstract: Developments and application of risk and reliability methods in the field of bridge management are constantly increasing to face safety and security aspects within limited budget constraints. The level of maturity of these methods varies significantly between different sectors and countries and there is a lot of potential for technology transfer. This paper presents a study undertaken within the EU thematic network SAFERELNET which aims at evaluating the current level of applications of these methods for the highway sector compared to other sectors and countries. The main barriers of progress are identified and recommendations are made for further work required to promote these applications in order to reach the level of application of other industrial sectors and maximise the benefits from their use. Fri, 29 Oct 2004 22:58:59 GMT http://ktisis.cut.ac.cy/handle/10488/7355 Title: Optimization of preventative maintenance strategies for bridges<br/><br/>Authors: Tantele, Elia; Onoufriou, Toula; Mulheron, Μ.<br/><br/>Abstract: The use of preventative maintenance (PM) has been acknowledged as an effective way of reducing the whole life cost of maintaining bridges in good, safe and functional condition. However, there are many uncertainties associated with the need and effectiveness of PM. Such uncertainties if not addressed can lead to incorrect decisions and wastage of resources. In addition optimization procedures are necessary to produce strategies with minimum cost while maintaining the reliability of the bridge at an acceptable level. This paper examines the issue of effectiveness of different PM on reinforced concrete bridges deteriorating due to the corrosion of reinforcement from chloride ions. It investigates the applicability of an optimization methodology, using the principles of genetic algorithm (GA) to identify optimum PM strategies based on their effectiveness and cost. Sat, 29 Oct 2005 22:58:59 GMT