Cross-section Whole Process Analysis Under Bending And Optimization Desgin Of Reactive Powder Concrete (RPC)-steel Composite Beams

Reactive powder concrete is a new kind of composite material of hyper-high-strength cement. It performs super high mechanical property, excellent durability, and inferior shrinkage and creep property. Taking reactive powder concrete in application to the structure of composite beams, the disadvantage on account of ordinary concrete itself, such as low tensile strength, cracking, connection performance deteriorating in long-term load contribution, can be made up. And it also can take full advantage of the composite beams which performs a light dead load, nice economic performance and convenient construction. As well, the characteristic of the two distinct materials, steel in tension and concrete in compression, can be fully exerted.In this article, a whole process analysis of reactive powder concrete-steel composite beam under bending has been proceeded, from loading to destruction. The influencing factors of concrete cracking and material nonlinearity have been taken into account. A numeral iterative program has been compiled to calculate values for plotting whole process moment-curvature curves under bending. The program is also applicable to steel-ordinary concrete composite beams. In specific examples, the moment-curvature curves of whole process have been calculated and plotted by the program. The curves have been analyzed and compared with the ordinary concrete composite beams. And the position variation of the neutral axis is also analyzed.In the article, a cross section optimality analysis has been done to reactive powder concrete-steel composite beams as well. According to in being design norm of steel structure, constraint conditions of the twain genera cross section, geometry and stress constraints etc., a mathematical model of cross section optimal design is derived. In examples, an optimal design analysis of a practical cross section has been proceeded, using sequence quadratic programming in Maltab Optimization Kit. Meanwhile, considering making good use of the two materials for their mechanical properties, another optimality analysis has been done with stress performance of the cross section. A correlation expression of concrete plating thickness and depth of composite beam is gained as optimizing the stress of cross section. The expression can be lent reference for the design of reactive powder concrete-steel composite beams. And it has been proven effectual in optimization of cross section stress performance via a practical example.