Quantifying the Value of B-WIM: Assessing costs and benefits for Value of Information Analysis

Implementation of B-WIM measurements and probabilistic approach in bridge assessment may reveal hidden bridge reserves and changes in reliability levels over its projected service life, providing this way a key input for optimized bridge management. But as both scientists and engineers and in the same time vendors of our own ideas, we need to be able to present the results of our sophisticated methods and algorithms, expressed mostly with safety or reliability indexes, probabilities of failures and similar indicators, with expected monetary (saving) values decisive for an owner or an investor.

So far, as presented at the IABSE Nantes conference 2018, in order to define the optimal management bridge strategy, a decision tree encompassing three B-WIM strategies (no B-WIM, short term B-WIM, long term B-WIM), two possible activities (no action, bridge repair/strengthening) and two possible outcomes (bridge is safe, bridge may experience failure) is set up.

In this paper, a further development of the decision and Value of Bridge Weight-in-Motion Information analyses in the context of assessing road bridges will be discussed. The focus is to present a detailed assessment and modelling of costs and benefits and associated indicators related to probability of bridge failure and bridge importance.

Costs required for the Value of Information analysis encompass: (i) bridge value as an initial cost of the new bridge CBV, (ii) direct costs of bridge repair/strengthening Crep, (iii) indirect costs of bridge non-availability due to repair measurements CN/A, and costs of B-WIM measurements (iv) CB-WIM,1 and (v) CB-WIM 2, applying short or long term monitoring respectively.