Study On Practical Evaluation Method Of Stress Loss For Prestressing Tendons Stretching Stage

In modern prestressed concrete structure,the loss of prestressed influence the crack resistance and the deflection of the structure directly. And in the stage of the control stress for prestressing, the loss of prestressed is a major part .so, Correct analysis of the the loss of prestressed in the stage of the control stress is one of the important research topic of the prestressed concrete. But the major loss due to the friction,and the difference between the practical and the theoretical calculation of loss is large. Accurate calculation of the loss is a very complex task. Prestressed actual greater than or less than calculated one , it can affect the structural performance(such as the deformation,the camber,the cracking load)which under the load.due to the service load, Lead high or lead the under-estimation loss value is disadvantage tous.This article through in the steel stranded wire's steel wire glue strain gauge, surveys the steel stranded wire stress the method to study opens pulls the stage loss of prestress the rule. Carries on Three continual rigid frame bridge different length pre-stressed muscle opens pulls the experiment, obtained each first-level tensioning force correspondence actual pre-stressed loss value and the elongated size, Analyzes the actual pre-stressed loss value and between the theoretical calculation pre-stressed loss value relations;Through to the proof stress data's regression analysis, obtains the loss of prestress and the tensile stress relations are two multinomial relations, According to theoretical calculation loss of prestress equation development loss of prestress empirical formula, as well as elongation quantity response loss of prestress empirical formula. Through to the elongation quantity data analysis, obtains different pre-stressed muscle length l, a corresponding at the beginning of tensile stress.This article research partial conclusions have the important theory significance to the pre-stressed construction appraisal, simultaneously also has the high application value.