THE FATIGUE PROPERTIES OF PRE-STRESSED CONCRETE STRUCTURE UNDER THE CONDITIONS OF FREEZE-THAW CYCLE

The fatigue damage properties of pre-stressed concrete specimen were analyzed under the conditions of different number of freeze-thaw cycle.The first-order fatigue load was applied to the concrete structures in the wake of freeze-thaw cycles.Based on the multi-level loading fatigue theory,taking the decay of a relative dynamic elastic modulus as the parameters to set up a multifatigue damage parameter,and using freeze-thaw damage factor k_n to express the effect of the freeze-thaw damage,thus a model of fatigue damage to concrete structures subjected to freeze-thaw cycles was established.The model takes account of the whole specimen injury.The tests show that the error between the calculated damage degree value by the model and that of the test is 16 percent.