Researcher: Saúl Cuendias González
Project Duration: January 2018- September 2018
Project Partner: Rijkswaterstaat
Problem definition and research goal:
Rijkswaterstaat, as the responsible party to find solutions to the infrastructure interventions to come in the following decades, with a more intense activity in the next 20-40 years (Figure 3), can have a great help of LCM in the decision making process. Within the ministry, in order to assess those increasing interventions due to functional and technical ageing, it has been started the “Replacements and Renovations Programme”. The main outcome of this programme is to predict the replacement costs in order to timely inform politicians about the allocation of necessary budget. Furthermore, it should be a useful way to decide what will be the required functional and performance demands for the new structure. Structures built now may still be in used after one century so the influences of the physical and socio-economic environment (now and in the future) have to be considered in order to redesign the structure according to new possible demands in the future. It is essential to give sufficient focus to the project definition phase on future changes (outside the project scope) because it can save a lot of money in time.
Considering the old bridge stock in the Netherlands and the high cost of replacing each structure, it is necessary to get an indicator of when a structure must be replaced. It is affirmed that more than half of the current and future structural engineering activities are and will be related to existing structures. Rijkswaterstaat has developed an indicator for the “end of life” of objects within the “Replacements and Renovations Programme”. It is called Economic End of Life Indicator (EELI) and it makes a statement on economic grounds to what extent the maintenance of an aging structure is still financially viable relative to a 1 on 1 replacement.
EELI is a tool to evaluate the technical aspects that lead to bridge replacement based on costs of maintenance or replacement. However, to reach an use of LCM, risks and performance should be addressed as well. Within Rijkswaterstaat, the risk analysis is well established within the RAMSSHEEP framework that evaluates the risks in terms of reliability, availability, maintainability, safety, security, health, environment, economic and politics. However, RWS only partially makes use of LCM and leaves out the factor that has decided most of the bridge replacement in the country: performance. From a total of 219 replacement projects, just 11.1% were related with technical reasons while the functional reasons correspond to the 88.9%. Technical problems are caused by degradation of the different parts of the bridges until when the bridge is no longer economically maintainable and has to be replaced. The functional reasons are related to more intense use, heavier loads, climate change, new regulations, urban planning, changes in societal needs or even improvements in technology that make the bridge unable to fulfil the requirements.
The research goal is to find a sound, standard and objective way to improve the decision-making process for bridge replacement due to functional reasons at Rijkswaterstaat using the Performance Age methodology. Subgoals are:
1. Define performance criteria/indicators related with highway fixed concrete bridges that are relevant for decision makers.
2. Determine where the Performance Age should be applied in the decision making process.
3. Determine which data monitored by Rijkswaterstaat can be used to objectively measure certain criteria/indicators.
4. Determine a pre-evaluation phase that could consider certain maintenance activities before the method is applied.
5. Improve the quantification methodology in terms of scaling and final Performance Age formula.
6. Determine the most proper way to relate EELI with Performance Age.
7. Put in practice the improved methodology to a larger stock bridge than in the current study and check its applicability.