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This paper compares the application of two recently published guidance documents for risk-based assessment of hydraulic actions on bridges, namely the UK Design Manual for Roads and Bridges and the Italian Ministry of Infrastructure and Transport's Guidelines, to two case study bridges (Staverton Bridge, UK; Borgoforte Bridge, Italy). This work is one of the first to illustrate how to apply these guidelines. Both documents present risk-based methods for the assessment of hydraulic actions, while exhibiting fundamental differences. For example, the UK method prescribes calculations for local and constriction scour, water depth, and velocity at several cross-sections; by comparison, the Italian method does not prescribe calculations to assess the risk level. For the case studies in this paper, the hydraulic risk obtained for Staverton Bridge resulted as 'High' using both methods. The scour score for the Borgoforte Bridge resulted higher using the Italian method (Medium-High), as compared to the UK approach (Medium). This difference is due to how the guidelines assess the vulnerability associated with the minimum clearance. The comparison of these two risk-based approaches and the resulting discussion may serve as a useful resource for those wishing to develop new risk-based methods for assessing hydraulic actions on bridges. [ABSTRACT FROM AUTHOR]

Bridge scour is a leading cause of failure for bridges over waterways and is notoriously difficult to detect with accuracy. Dynamic Structural Health Monitoring (SHM) of bridges for scour has gained traction in recent years as monitoring systems have improved and the reliability of measurements increased. Due to the large number of bridges on typical networks and the limited financial resources within asset management agencies, decision-makers must prioritize certain structures when it comes to management in the event of flooding. The decision to install a dynamic SHM system on a bridge must be balanced by the financial benefit of doing so, as limited resources often need to be carefully rationed. In this paper, a methodology is proposed to evaluate such benefit based on the Value of Information (VoI) from Bayesian decision analysis. A case study is presented whereby a dynamic SHM system is considered to be installed on a typical bridge with the aim to support emergency management operations during flooding. The proposed methodology allows computation of the financial benefit of installing a dynamic SHM system over a certain reference period, thus accounting for multiple flood events and scenarios. The various elements of the procedure are discussed in detail. [ABSTRACT FROM AUTHOR]

Scour is a significant cause of bridge failure, and resulting bridge closures are likely to generate significant disruption to infrastructure networks. The management of scour-susceptible bridges is a significant challenge for improving transport resilience, but tends to be heuristic and qualitative. Such assessments often suffer from insufficient knowledge of key factors and require assumptions, which may increase their estimation and relative uncertainty. Analysis of publicly available technical documents reveals that various definitions of "risk" are adopted, as well as multiple approaches are applied. This paper has three objectives: (i) to illustrate the concept of risk in bridge scour management; (ii) to propose a simple scoring system to analyse existing risk-based approaches to manage bridge scour; and (iii) to analyse and compare such approaches on the basis of the obtained scores. A sample of nine documents containing bridge scour risk assessment practices or approaches was analysed using the developed rating system. [ABSTRACT FROM AUTHOR]

The management of civil infrastructures in the aftermath of a seismic event is a concern for decision makers, which have to choose quickly among alternative actions with limited knowledge on the actual structural conditions. The availability of real time Structural Health Monitoring (SHM) data on the asset might be particularly useful. However, SHM data are not collected for free, and the cost of the SHM system should be compared with its associated benefit. A powerful tool to estimate such benefit is the Value of Information (VoI) from Bayesian decision theory. This paper provides a methodology to compute the VoI of SHM for seismic emergency management of roadway bridges. This methodology can be used by decision makers before the installation of a seismic SHM system to quantify the cost benefit of doing so and thus optimize the allocation of economic resources. Results show that the VoI is high when the expected costs of the decision alternatives (such as 'keep the bridge open' or 'close the bridge') evaluated without the SHM information are comparable. In this condition, which is highly dependent on the seismic hazard and on emergency management costs at stake, the SHM information provides the maximum support to decision making. [ABSTRACT FROM AUTHOR]