To replace or not to replace: a model for future functional performance of bridges Asset Management; Bridges; Functional Performance
Sander Mooren*, Andreas Hartmann, Sahand Asgarpour; CME | University of Twente, Netherlands Introduction ▪ Asset managers at road agency are, among other tasks, responsible for managing bridges. A focus exists on technical and economic end-of-life, although in practice bridges often get replaced for functional shortcoming; the functional performance no longer meets the functional requirements. ▪ Asset managers aim to optimise value by balancing life cycle costs, risks and performance. Nevertheless, it is a challenge to formulate bridges’ life cycle performance. For this thesis, a model has been developed to aid asset managers by providing insight into the future functional performance level of bridges. ▪ Research question: How does functional performance of bridges and viaducts as part of a network develop over time (1) and how can these insights contribute to infrastructure asset management decision making (2)? Research design ▪ A model has been developed to forecast bridges’ functional performance level. The develop model has been built as an extension to a base model. The base model contains road segments’ traffic intensity and capacity from 2019 to 2050 under 4 future scenarios. The scope of the model is national roads in the Randstad area in the Netherlands. ▪ Expert interviews, scientific literature, internal documents from Dutch road agency Rijkswaterstaat, and legal documentation have been used in the development of the model. ▪ First, indicators for bridges’ functional performance have been selected. Subsequently, a theoretical foundation for these indicators has been built, before software implementation took place. After implementing the model and running the simulation for 4 scenarios, the output has been reshaped to present it in various different visualisations. Results ▪ ▪ ▪ ▪
The selected indicators are: Intensity/Capacity ratio, Automatic Incident Detection (AID), Lighting, Noise. 1183 bridges have been linked to the base model. The simulation’s output gives a 4-dimensional data cube (bridges, indicators, time, scenario) By performing different operations on the data cube, asset managers obtain various visualisations. This gives asset manager more insight into the functional performance of bridges.
Discussions ▪ The base model is not flawless in its traffic assignment. As a result, the model may prematurely label a bridge as having reached its functional end-of-life. ▪ The traffic intensity of the other side of the viaduct is in many cases unknown. Thus, a bridge could reach its functional end-of-life which the model does not identify. Conclusion ▪ The developed model allows asset managers to account for the future functional performance level of bridges. As a result, interventions can be scheduled more efficaciously.
*Contact: s.c.a.mooren@utwente.nl
Asset managers can improve the life cycle performance assessment of bridges by forecasting the functional performance using a road network model.