Probability Of Flexural Fatigue And Straight-resistance Of Steel Fiber Reinforced Prestressed Concrete Slab

With national construct of express highway quickly developing, it requires bridge structures higher and higher. At the present time, prestressed structure has already been prevalent in the development of the bridges. But with the advancement of the theory and technology, it requests that more scientific and logical structural form be used in practice. Technical and theoretical characters of Steel Fiber Reinforced Prestressed Concrete (SFRPC) structure meet the requirement. It is obvious that SFRPC Structure should be used extensively because of the rationality of its technology and economy.This paper introduces the mechanics performance of steel fiber concrete and the characteristic of the prestressed structure at first. This performance of SFRPC slabs under four-point flexural static loading and flexural fatigue loading are tested in terms of three fiber contents. Three different levels of applied fatigue stress are considered. Comparing with the behavior of SFRPC beam, the formula for the straight-resistance of SFRPC slabs is established on the foundation of flexural static loading test results. According to fatigue experiment results, the fatigue equation and equation of surplus strength degradation are built. The law of degradation of flexural rigidity is analyzed. Based on the fatigue cumulative damage models, a damage evolution equation for flexural fatigue of SFRPC slabs is set up.It can be summed up from the study results: the static flexural strength of SFRPC slabs is better; at the same fatigue life, SFRPC slabs can bear higher stress level with the fiber content increasing; at the same stress level and cycles, the surplus strength of higer content of SFRPC slabs is higher; at the same cycle ratio, damage of higer content of SFRPC slabs is lower. In conclusion, the function of steel fiber is obvisous.