Research On Strut-and-tie Model And Reinforcement Design On Spiral Structure Of Hydrostation

According to the theory of strut-and-tie model(STMs) design the interference area of reinforcement concrete which belong to non-member systems and irregular structure, is a hot research point at home and abroad currently. The theory makes up the shortcomings of traditional method which excessive depend on experience formula in interference region, it improves the science and accuracy on reinforcement design. At present,Europe and United States have taken the method into the specification of concrete design. In recent years, many scholars have carried out extensive and in-depth study on the strut-and-tie theory, but their results mainly concentrated in corbel, bridges and other civil engineering structures and so on, and their study didn’t related to reinforcement design of hydropower structures such as spiral case structure.As a result,this paper proposed and studied the STMs and reinforcement method on hydropower spiral structure design, developed the reinforcement design of volute structure to a theory based on fine mechanics model, enriched the theory of design concrete reinforcement on spiral case structure in hydropower station, it has good scientific, practical and convenient. The main research contents and results in this paper are showed as follows(1) Respectively studied the basic steps of how to estable STMs ofspiral case according to topology optimization method and stress trace method, then according to this two methods established two categories of STMs.(2) Deeply tudied different STMs respectively which is built according to the same method, the contend different times statically indeterminate, different levels of refinement and different arrangement of struts of STMs and so on. The results shows that, based on low-order model statically indeterminate design reinforcement is safer.(3) Presented the method of reinforcement design according to the internal ring sterss envelope gotten by different types of STMs, it improves the safety and reliability of the volute structure reinforcement design.(4)Compared the internal ring sterss envelopes gotten from topology optimization method and draw force trace method. Concluded, based on the envelope that the topology optimization method for reinforcement design is safer.(5) Compared the calculate results of calculate model belong to the topology optimization method and stress trace method corresponding. The results showes that the internal force distribution regularity of this two methods is basically the same, shows that the reliability of STMs calculate method on spiral case.(6) Designed the spiral case structure reinforcement according to pulling pressure bar method and stress graphic method respectively and compared each other. The result show that the reinforcement result of STMs method is relatively smaller than stress figure method, but the STMs method is based on the theory of mechanics, which can reduce the phenomenon of excessive reinforcement.