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The main objective of WP2 is to develop CEEC-appropriate techniques for optimal bridge assessment. According to the findings of previous European and other international projects (SAMARIS, COST345, PIARC C11), there are great variations in the composition of actual heavy traffic from country to country. For example, SAMARIS has found that trucks in EU-15 and EEA (European Economic Area) countries are much heavier than in NMS and CEEC – an average difference of 20% in traffic loading was found between 3 sites in the Netherlands and 3 sites in Slovenia. Therefore highway structures in NMS and CEEC have additional reserves in structural safety that, if known, can considerably reduce the required rehabilitation of bridges that have deteriorated.

Unfortunately, traffic loading conditions in NMS and CEEC highway structures are mostly unknown. The reason for such a situation is a lack of consistent systems that collect traffic data in a way appropriate for bridge design and assessment. The load carrying capacity of many highway structures is not known either, especially for very old bridges where the design and construction documents are not available. With that many unknowns, both on the loading and on the resistance sides, it becomes really difficult to obtain a reliable estimate of the actual bridge safety and serviceability and propose optimal rehabilitation measures.

Load testing of bridges has considerable potential to improve knowledge of load carrying capacity but is currently generally only practiced for new bridges and the information found is not used for assessment. The ARCHES project will develop the new "soft load testing" concept, where bridge response to regular traffic is used as a measure of the bridge condition. Over an extended time, this will provide highly useful condition data to bridge assessment engineers with minimal cost.

Gathering information on the actual traffic load on bridges and actual bridge condition is essential for improved management of highway structures. Using the advanced monitoring techniques available today (and being developed in projects such as INTRO) to gather the missing traffic load information and employing load testing, the work package will provide documents, guidelines and Internet tools which, if used, will avoid unnecessary interventions for a huge number of bridges.

The last part of the work package deals with the assessment of different pavement unevenness repair strategies to reduce dynamic impact on bridges. In the task, the dynamic increment appropriate to critical multiple-truck bridge loading events will be found for a range of bridge types and spans.