Slotted Prestressed Pier Stress Concentration Features

As a supported structure for a large-scale arch gate, a pre-stressed pier has been widely applied to hydraulic engineering. For the conventional applications in real engineering, the problems of a large tension-anchor coefficient lead commonly to an impropriety structure for the pier. In the conjunction of the rope anchored pre-stress and the hydro push force from the arch gate, a high stresses and complex stress state are often created in the anchor block. A method to solve the problem is to build a rectangular opening in order to release the high stresses in the anchor block and to improve the stress state of the pier. However, a rectangular opening in the highly stressed anchor block will naturally cause stress concentration around the rectangular opening. Therefore, a suitable choice of the rectangular opening position, size and geometrical configuration is to become very important to the design of a pre-stressed pier. This thesis studied the problems of stress concentration due to a rectangular opening in the anchor block of the pier. The tasks done are as follows:1. A complex function method based on the least square method is used to analyze the stress concentration around an opening in the finite domain, and the theoretical formulae of the computational complex function method (CCFM) are established. A computing program has been written in the Matlab language for a rectangular opening and lots of calculations have been done. The results show that the analysis method suggested in this thesis is effective for analyzing stress concentration in a pre-stressed pier.2. The stress around a rectangular opening in the finite domain has been computed with CCFM, the phenomenon of stress concentration was analyzed, and the distribution change law of the stress as the opening configuration and size was obtained.3. A pre-stressed pier of a large-scale hydro power project was studied by using a FEM software — ANSYS and CCFM. Comparisons of many projects of the opening positions and configurations were done. A suitable opening project was obtained and used in the engineering.4. The results of the study show that a suitable setting of a rectangular opening in the anchor block can have a good utilization of the stress concentration in the anchor block and get to an objective to improve the stress state in the pier.