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SAMCO Final Report 2006 F09 Report on Bridge Management

The planning of maintenance interventions is possible only by knowing the perform- ance of the structure in terms of durability and evolution of defects. This knowledge needs to be continuously updated with observations and information necessary to create the predictive models of the structural and functional degradation of the bridge.

A large part of the bridges in the new member states are not as well maintained as the bridges in the EU and will need substantial repairs and upgrades, before they fulfill the requirements for bridges in the EU.

For these reasons, special attention is focusing on the evaluation of the long-term performance and residual life in the project SAMCO on the monitoring and assess- ment of bridges considered to be main activities in the general sector of the man- agement of bridges.

3.2 Factors affecting the long-term performance of bridges

Bridges are designed to carry traffic across an obstacle, their minimum length varying among the different countries form a minimum of 2m. (France) to 10 m. (Italy). They are supposed to resist loads from a number of different sources such as the weight, traffic, impact, horizontal forces and the environment. Of course, bridges should be designed for a given economic service life and of course they are supposed to resist in a harsh environment. However, during their service life, bridges are likely to dete- riorate as a result of a loss of strength due to structural damage and for material deg- radation, but to remain serviceable.

Their performance is influenced by the interaction of two main factors: the environ- ment and the traffic.

Even if these two mechanisms are generally known, it is quite difficult to assess their effects, to predict their evolution and to determine the consequences on the response of bridges.

First of all it is difficult to describe them in detail to choose adequate preventative measures at the design stage. For instance, when a structure or a component starts deteriorating, the process of damage of the whole bridge tends to increase as the presence of deteriorated parts might reduce the load carrying capacity and make the structure more “vulnerable” under heavy loads, as it might be the case of fatigue of materials.

Not all the factors that interfere in the service life of a bridge may be considered since the design stage. National and international standards and recommendations give only the criteria for modelling traffic and other actions generated by environmental factors, such as earthquakes, wind and thermal effects. Other types of actions, such


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