Under Freezing And Thawing Cycles On Prestressing Tendons Loss

For prestressed concrete structures,the freeze-thaw cycle will affect the size of the prestressed concrete prestressed,causing loss of prestress,prestress loss is structure the influence factors of crack resistance and stiffness cannot be ignored,too much loss of prestress,not only reduces the prestressed structure itself,but also reduce the crack resistance of components,reduce the rigidity of component,and may lead to the failure of the prestressed,further to the structure,ultimate bearing capacity and crack resistance effect,on the durability of concrete structure itself is a can't ignore the influence of the factors.This paper around the loss of prestress and prestressed steel strand strength grade,the relationship between the three aspects of research:(1)Theoretical analysis: this paper introduces the structure of the prestressed concrete specimens in the laboratory under the normal temperature condition the influence factors of prestress loss and the calculation and analysis;And under the condition of freezing and thawing cycle,prestressed concrete component generated by internal stress changes are analyzed in theory and speculation;Discussed under the same external conditions at the same time,the changing rule of the prestressing loss increased with the increase of number of freezing and thawing,under the same freeze-thaw cycles,the loss of prestress with the outside world the impact of the increase of the degree of freeze-thaw conditions.(2)the test analysis: the experiment adopted two kinds of environment,respectively,to determine the test component after 120 after repeated freezing and thawing effect of prestress value,and describe the various strength according to the results of the experiment of prestressed steel strand,prestress loss curve under different conditions of the prestressing loss value of contrast and analysis.(3)using ABAQUS software to simulate,with different strength grade of prestressed steel strand under the effect of freezing and thawing cycle produced by the loss of prestress,paint a different strength grade of prestressed steel strand prestressing value table of comparison and contrast curve,by comparing the different strength grade of prestressed worth the strength of prestressed steel strand and the relationship between the prestressed loss under freeze-thaw cycles.The results show that under the same circumstances,with the increase of number of freezing and thawing,prestress loss is more and more big;Under the same number of freezing and thawing,with the increase of the outside world degree of freeze-thaw conditions,the prestress loss is more and more big;With the increase of prestressed steel bar strength grade,prestress loss is more and more small.