Study On Optimization Of New Shape Pre-Stressed Pier

Pre-stressed pier is used as supporting structure of large-scale arc-type gates, which has been widely applied in hydraulic engineering. However, the pull-anchor coefficient is generally too high in the present pre-stressed piers, the structure is not reasonable. The stress in a pre-stressed pier is quite complicated and the stress is very high due to the combined action of the pre-stress of anchor cable and the huge thrust of arc-gate. To release the stress in an anchor block, various new cavity pre-stressed piers have been applied, formulating some computation theory and method. However, no detailed work has been reported in determining the position, size and shape of a cavity. The pre-stress in the concrete part of an anchor head is enormous, and the limit bearing capacity is very important for choosing a pre-stress tonnage.A new pier structure is studied in the present work---cavity structure necking pre-stressed pier. The finite analysis software ABAQUS has been utilized to simulate different load conditions, optimizing the position, size and shape of the cavity in anchor blocks in order to search for a reasonable cavity pier structure,In addition, the refined finite element elasto-plastic analysis has been conducted to investigate the limit bearing capacity in the concrete part of an anchor head Three-dimensional finite element model has been built by using ABAQUS to investigate the stress status in a pre-stressed pier and pier block under different load conditions and to analyze the stress distribution in the anchor block, appraising the structure of a cavity structure necking pre-stressed pier by comparing with the non-pre-stressed pier, simple anchor pre-stressed pier and necking pre-stressed pier. The stress distribution in the slotted anchor reservation cavity has been studied for different thicknesses, and the effect of the cavity position on the stress distribution is also investigated. The optimal thickness and position of the cavity is determined at a given working condition and load condition. The feasibility of non-rectangle cavity layout has been analyzed. Replacing the rectangle cavity with the rectangle circumscribed arched structure, and four camber heights are studied to search for the optimal one. The perpetuation tension tonnage of an anchor cable has been optimized in order to improve the preloading effect of the anchor cable. The limit bearing capacity is obtained by using the refined finite element elasto-plastic analysis on the concrete in the anchor head part.The present work gives detailed analysis on the stress distribution of new cavity structure necking pre-stressed piers and on structure optimization, which provides some guidance for designing a new arc-gate supporting structure pre-stressed pier.