CONSISTENT ANALYSIS METHOD FOR LONG TERM EFFECTS IN COMPOSITE BRIDGES

theories. Some of the arising problems and their solution in the design and anal ysis process of composite bridges will be described in this paper. The basic theory needed for the proper numerical modelling of long-term effects combined with the specific structural behaviour of the bridges will be outlined. A consistent solution is proposed for both linear elastic theory and non-linear theory. The presented solution has been implemented in a commercially avail able computer program. This implementation into the bridge design software is briefly descri bed. The system takes into account all types of quasi-permanent loading and the time, when it is a pplied on the structure. The structural calculation includes the computation of the effects due to creep and s hrinkage in the time intervals between activating new structural components and applying major n ew loadings. With such tools, the structural engineer is able to predict and follow the struc tural and material behaviour through all steps of bridge construction. A geometrical pre-processor and a po werful graphical post-processor facilitate the comparison of the behaviour and costs of different variants withi n short time. Various composite bridges have already been successfully desig ned and analysed by applying the presented solution. The bridges presented in this paper as typical ex amples are suited to give insight into the problems specifically related to composite behaviour that we re encountered and solved in the design process using the presented solution.