The Life-cycle cost of bridges – first steps to a holistic approach

Bridges create transport infrastructure and are subjected to long term witness of economic design, reliability, durability, maintainability and external risk (natural and human hazards). Deficient design of bridges points to high investment costs, low quality, retrofits maintenance costs, mitigates quality damages. The primary reason of the problem is usually stated high investment costs. Resources for investment are limited over and over again. However, approach for evaluating and comparing the cost effectiveness in practical design does not dominate in present-days as arbitration of different strategies and warrant for avoiding critical economic or functional situations. This paper illustrates a method for estimating the retrofits for bridges design based on Life-Cycle Costs and Cost-Benefit Analysis. The approach integrates cost model, fragility of as-designed and retrofitted benefits for a range of externalities and associated potential changes in design and economical retrofit. The emphasis on life-time performance and benefits, as opposed to initial retrofit acquisition investment cost alone, paves the way to risk-wise investment and also helps to support upgrade actions for sustainable infrastructure. An application of the holistic approach Life-Cycle Cost and benefit analysis is conducted for two representative bridges of highway class. The available financing has a big influence on the chosen technical design.