Long-term asset planning for port facilities: utilising asset service life variation to facilitate smooth replacement efforts and reduce costs

Many assets deteriorate gradually over time. Their condition is monitored throughout this period. An asset is replaced when it reaches the end of its useful life. This study looks at assets that form part of a larger population and can share functions. These assets are for example found in ports and are used for quay wall facilities. Their service life is shorter than that of the quay wall itself. As assets do not all age at the same rate, this study investigated how these differences in service life could inform better replacement planning. Condition data were converted into service life data and their distribution was obtained by performing a goodness-of-fit test. A simulation model was developed that predicts asset failure over time and replaces groups of failed assets once the maximum number has been reached. This model uses service life distributions to provide expected times for group replacements and associated discounted costs. This approach helps asset managers improve long-term planning and decision-making regarding the optimal size of replacement groups. A case study of purlins shows realistic savings of between 5% and 20% without economies of scale and even greater savings when they are included.