Study On The Application Of Steel-Concrete Composite Structure In Very Large Floating Structures

Steel-concrete composite structure can make full use of the advantages of steel and concrete,and has excellent comprehensive mechanical properties.It has important application value and broad development potential in offshore very large structure which has high requirements for structural safety and economy.In this paper,the application of steel-concrete composite structure in offshore very large floating structure is studied in detail.A variety of new design schemes of very large steel-concrete composite structure are proposed,the corresponding hydroelastic analysis software is developed,and the mechanical behavior of the structure is analyzed based on the study of local components and the whole structure,which provides important design reference for the application of steel-concrete composite structure in very large floating structures.The main research results and findings are as follows:(1)A variety of design schemes of offshore very large steel-concrete composite structure are proposed.According to the mechanical characteristics of offshore very large platform and steel-concrete composite structure,several offshore very large steel-concrete composite structure schemes corresponding to pile-type,pontoon-type and semisubmersible-type are proposed,which lays a foundation for the application of composite structure in offshore very large platform.(2)The development of hydroelastic analysis software and parameter analysis for very large floating structure.The program package THhydro,which supports hydroelastic analysis based on mode superposition and multi-body interaction is developed.The program has been verified by a number of experiments.At the same time,hydroelastic parameter analysis of very large floating structure is conducted,and a fast prediction and estimation method of hydroelastic response based on machine learning is proposed,so as to simplify the preliminary design process and shorten the design period.(3)Analysis and discussion on the key components and sections of composite structure.Three cross-section forms of double steel-concrete composite slab for floating platform are proposed,and the response characteristics of each cross-section form under different load modes are compared and analyzed from cross-section level and component level,and the design suggestions of steel-concrete composite slab in offshore structures are given.Based on theoretical analysis,the equilibrium differential equation and the theoretical solution of critical buckling load of steel-concrete-steel composite slab are given.(4)The design and analysis of very large steel-concrete composite floating structure.Case design of very large steel-concrete composite pontoon-type floating structure and the composite submerged structure of very large steel-concrete composite semi-submersible floating structure are carried out.The quantitative parameters including steel consumption,self weight and other design indexes of the composite structure platform are given,which provides design reference for the application of steel-concrete composite structure in very large floating structures.At the same time,the influence of the ratio of steel to concrete on the design indexes of the structure is given.The research shows that the application of composite structure can reduce the steel consumption and cost of the structure effectively.Moreover,The influence of the parameters of multi-body connectors on the hydroelastic response of very large floating structure is studied.