Experimental study on strain performance of tensile reinforcement under fatigue loads

As for the study on the strain performance of tensile reinforcement under the fatigue loads with amplitude of certain values, two groups of reinforced concrete slab bridge specimen were made. The fatigue test was carried out on one group of specimen, and the corresponding static load test was carried out on another group of specimen, the experimental study on the strain performance of tensile reinforcement was carried on bottom of the mid span of slabs. The results of the study shown that, under the fatigue loads at a certain amplitude, the strain performance of the tensile reinforcement tend to be stable with the increase of number of fatigue cycle, the strain value showed certain linear relationship with static load applied. When the fatigue amplitude increased, the change rule of strain with static load value applied was approximately linear, but the strain value increased more than the fatigue amplitude less under the same static load. It could be seen through the comparison of load - strain curve of the static load specimen, after effect of compressive fatigue with certain amplitude, the strain change with load applied was close to linear change, which has great relationship with the effect on concrete and reinforcement plastic deformation by fatigue load. The test results had the vital significance of further research on reinforcement performance under the action of fatigue loads.