Different bridge maintenance strategies and life cycle costs: Comparison of costs in Croatia, Slovenia and the Netherlands

Bridges are highly complex structures exposed to heavy environmental and mechanical loads, which require immense financial investments in all life cycle periods, from planning, design, operation and end of life phase. The longest period in whole life cycle of a bridge is operational phase which includes numerous maintenance and repair activities. Timing of these activities and their extent is a crucial factor that influences bridge future performance. Traditionally, the decision to perform maintenance is based on the infrastructure managers' observations, judgments and choices which are derived from inspection results, available budgets and abrupt failures. Though, maintenance based on these drivers very often leads to undue maintenance with increased cost. For this reason, predictive maintenance is considered to be a most effective maintenance policy that suggests to perform maintenance only where it is promptly needed. However, predictive maintenance poses decision-making challenges for infrastructure managers. Particularly for road infrastructure networks, the maintenance decision-making is a difficult task due to a widespread network of diverse infrastructure objects, availability demands, deterioration rate and budget constraints. Such infrastructure maintenance requirements pose decision-making dilemmas to the infrastructure managers, where maintenance planning is challenged by the number of conflicting issues (e.g. limited budget vs. aging network, the risk of failures vs. traffic intensity over an object). This paper tries to examine the effect of two opposing maintenance strategies for life cycle management of bridges, corrective and preventive maintenance based on historical data about bridges in three countries and 30 years of experience. The maintenance costs for bridge structural elements at different condition levels are analysed, based on the data from three countries, Croatia, Slovenia and the Netherlands, where different approaches to maintenance strategies are being applied. The overall maintenance costs over a longer period of time, up to 30 years are collected and analysed, with the aim to clearly define pros and cons for both approaches

Robustness of the Multi-Attribute Utility Model for Bridge Maintenance Planning

Optimisation of maintenance planning is an essential part of bridge management. With the purpose to support maintenance planning, a multi- objective decision-making model is introduced in this paper. The model is based on multi-attribute utility theory, which is used for the optimisation process when multiple performance goals have to be taken into account. In the model, there are several parameters, which are freely chosen by the decision maker. The model is applied to the inventory of 22 bridges, where four Key Performance Indicators were determined for four performance aspects:  reliability, availability, costs and environment. A sensitivity analysis is performed by changing risk tolerance parameter and attribute weights to determine the robustness of the model. The Multi-Attribute Utility model and sensitivity analysis presented in this paper will help decision-makers to examine the robustness of the optimal solution by dynamically changing the critical parameters

WG5 technical report drafting of guideline/recommendations of COST ACTION TU1406

[Excerpt] This report assimilates and synthesizes the work carried out by COST Action TU1406 - Quality specifications for roadway bridges, standardization at a European level (www.tu1406.eu) in various Working Groups. The objective is thus not to create new information but to highlight and emphasize the key recommendations and guidelines developed in various working groups. The recommendations and guidelines are not prescriptive, but suggestive and allows a diverse range of methodologies already in operation in various bridge networks to align to it. The need for a homogeneous approach for the maintenance and management of road bridges in EU, while acknowledging the disparate processes of such management is key to understanding this report