Life Time Assessment of Exisiting Bridges

摘要

The prediction of a realistic lifetime and the prolongation of the service life of a structure is an important task to reduce costs. The usual theoretical predictions are not very reliable. The prediction model used consists of a load model, a system-transfer model and a damage model. The results of these sequentially coupled models are usually unreliable, especially the influence of the uncertain load and damage models controls the reliability of the result. A method based on monitoring strategies is presented, which avoids these problems. Expected trends of future traffic, are considered. If the remaining life time of existing structures should be assessed, information about the strain time history of the past is needed. It is shown how these data can be generated taking into account the estimated statistics of the load in the past, the dynamic behaviour and the bumpiness of the road. Synthetic time series of the local strains are generated which include the real statistics of the process and cluster effects induced by truck convoys.