Structural Health Monitoring of UHPFRC constructions - possible application in post earthquake assessment of bridges

The paper discusses the behaviour of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) constructions and application of bridge systems in regions with high seismic hazard. On the one hand side laboratory tests for analysing the material were carried out and on the other hand side a permanent bridge monitoring system of the 2nd generation was established on a road arch-bridge with UHPFRC as structural system. Safety relevant structures and lifeline structures demand a quick assessment of the safety and serviceability/operability immediately after an earthquake. Continuous monitoring systems providing information about changed modal parameters as a consequence of damage are going to be used to trigger warnings and alarm in future. The measurement system must be a "tailored -one", which works together with an expert system. Warning- and alarm levels have to be elaborated in advance by sensitivity studies carried out with a structural model fitted to "reality" (using test results). Such expert systems have also to consider the influence of changing environmental conditions, especially temperature. For this aim laboratory tests on UHPFRC specimens under changing boundary conditions were carried out. Next to dynamic analysis in a climate chamber different load steps up to construction failure were analysed with non destructive testing methods. Due to material properties of UHPFRC, high stiffness by low mass and ductile behaviour, it should be predestined for bridge structures in high seismic regions.