Integral Finite-Element Analysis Of Pre-stressed Concrete Structures

Pre-stressed concrete construction has been widely used in many engineering areas such as building, bridge and hydraulic engineering. It is still an active research topic for structural engineers and researchers to develop new methods or computational model for more accurate and efficient analysis of pre-stressed concrete structures. In the conventional analysis, the effect of the pre-stressed reinforcement on the concrete structure is generally treated as a group of constant external loading, and the interaction and compatible deformation between the two components are often ignored. Under these circumstances, it is difficult to ensure the accuracy and reasonability of the analysis results.In this thesis a new integral finite-element model for the analysis of bar-type pre-stressed concrete structures such as continuous beams and frames, has been developed. In the model, the pre-stressed reinforcement and the concrete frame are treated as an interactive integral, and both of the components are discretized using different types of elements. The analysis of the model can be readily achieved using general frame structural analysis programs.In order to demonstrate the validity and accuracy of the proposed method, a two-span pre-stressed concrete continuous beam was first analyzed. The computational results were compared with the results using the conventional equivalent loading method as well as the exact elasticity solution. It indicates that the new method is feasible and more accurate and efficient than the conventional analysis methods. A single span two-story plane frame and a two-span two-story frame under the pre-stressing and loading stages were then examined respectively. The obtained results were compared with those from the equivalent loading method. It is shown that the present method is not only of simplicity in its computational procedure but also capable of more accurately and reasonably representing the interactive behavior between the pre-stressed reinforcement and the concrete structure, particularly under the loading stage of the structure.