The Comparative Study of the Vertical Prestress of Steel Wires and Fine Rolling Twisted Steel

Through the contrastive test on the vertical prestressed steel wires and fine rolling twisted steel,the paper studies the principles of the two vertical prestressed steels and analyses the features and the pre-stress loss of these two systems.The results indicate that the loss rates of the first tension pre-stress of the two steels are basically the same and so do the long-term loss rates.However,the second tension effect of the vertical pre-stressed steel wires is more obvious and its loss rate is reduced about 1/2 compared to the first one.There is a higher degree of reliability on vertical pre-stress of web of the box-girder which has larger controlled tensile stress.It proves the practical significance of using the steel wires as the vertical pre-stressed wire and provides a reference for the engineering design.