ProTimB - Monitoring of Structurally Protected Timber Bridges

Timber bridge construction has a millennia-old tradition worldwide. In the course of industrialization, other building materials have become increasingly popular. In order to build durable and therefore competitive bridges made of timber, they must be protected against precipitation and the ingress of moisture. A low moisture content is the key to the durability of wooden structures. Consequently, all structural components of timber bridges should be constructively protected to reduce the negative impact of precipitation and moisture. To evaluate the efficiency of constructive wood conservation measures under real conditions a monitoring program was initiated in frame of the research project “Protected Timber Bridges” (ProTimB) sponsored by the German Federal Ministry of Education and research (BMBF). The aim of the program is to demonstrate the durability of well protected timber bridges. Furthermore, problematic details and special local climate conditions should be determined. Therefore, nine timber bridges in Germany were equipped with a monitoring system to measure the timber moisture content and ambient climate conditions. The structural types are timber concrete composite bridges, trough bridges, arch bridges, beam bridges and truss bridges. The monitoring system works on the principle of the electrical resistance method that is based on the dependence between electrical resistance and material moisture content. Influencing factors are the material temperature and the wood species. The paper describes the structure and application of the monitoring system. Measurement results and conclusions are presented.

References

 

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