Abstract:

Steel structure has multiple advantages such as low carbon and environmental protection, light weight and high strength, and excellent seismic performance, and has been widely used in high-rise buildings, large-span buildings and some civil buildings, but its inherent susceptibility to buckling, corrosion, and high cost impede the further application of steel structure. Current measures to prevent buckling and corrosion of steel structures can greatly increase the cost of the structure and have a negative impact on the structural load-bearing capacity. Ultra-high performance concrete (UHPC) is a new type of fibre-reinforced cementitious composite material based on the theory of maximum packing density, which has high strength and deformation capacity, and has excellent performance in terms of water permeability, chloride permeability, and freeze-thaw resistance and other durability. Nowadays, they are widely used for mechanical and durable reinforcement of various structures. Recent research work has shown that the combination of steel structures and ultra-high performance concrete (UHPC) can effectively complement each other. This paper is based on a new type of combined beam of I-beam covered with a thin layer of UHPC, which has been widely used, and a sample database is established by ABAQUS finite element analysis software. Using the radar diagram method to put forward the combined beam shear performance and shear cost-effective comprehensive evaluation indexes, using the response surface - Monte Carlo method, the design of four kinds of response surface combined beam web size parameters for analysis. The analysis results show that there is a significant positive correlation between the shear performance of the combined beam and its cost-effectiveness. In addition, with the increase of I-beam web thickness, the shear resistance and cost performance first increase and then decrease, and reach the peak value at a specific thickness. The results of this paper are of great engineering significance for optimising the design of I-beam outsourced UHPC composite beams.

Key words: steel-UHPC combination beam, cost-effectiveness, finite element simulation analysis, radargram method, response surface-Monte