Nonlinear Structural Analysis And Improved Design For Scroll Case In Hydropower Station

Steel Lined Reinforced Concrete Penstock (SLRCP) was firstly applied to hydroelectric power stations in 1960s. The structure of scroll case, the heart of a power station, is a complex structure of SLRCP which has specific advantages. Now this kind of scroll case is adopted in most of power stations.However, some problems are brought out. (1) It is difficult to determine the complex stress state of this kind of scroll case structure due to the coexistence of the nonlinear constitutive and elastic linear constitutive material in the scroll case structure; (2) The constitutive material do not act fully; (3) It is not clear how the components affect the formation, development and distribution of cracks.Therefore, this paper is focused on the above questions. To make the research results more practical, finite element models for the scroll case structure of several real hydroelectric power stations are created. The following aspects are studied:1). The study of the method of scroll case structure by finite element method. A scroll case structure simulating model is accomplished by ANSYS. This model including: three different components (steel scroll case, reinforced concrete structure and concrete structure) and the interaction between them; according the formulas for crack and the characteristic of scroll case structure, the formula for scroll case's crack is achieved. These lay the academic foundation for optimal design of scroll case structure;2). The analyses of some real scroll case structures through the simulating models. The distributing drawings of stresses of different components in the scroll case structures are achieved and their effects to the whole structure are known; the loads applying the structure are analyzed and the crucial loads are found out. These supply references to optimal design of scroll case structure;3). The optimal design of scroll case structures. Considering the calculation results, the relations between the rebar and the crack development are concluded, the best way to lay the rebar is chosen which make the components play a full role. All kinds of structural styles are analyzed by dynamical method, and the reasonable style is forward out. According the effect of different pre-cast water head, the conclusion is drawn on the choice of pre-cast water head. The scroll case structure is studied from these aspects, which are used in the optimal design project.The research results of this paper are used in some practical projects and are proved correct and reliable. Thus the work simplifies the design methods of the scroll case structures and promotes the development of the corresponding theory. On the other hand, it also promote the corresponding theory.