Abstract:

In order to obtain reasonable sequence of prestressing tension,we put forward a new way by using characteristic parameters to guide prestressing tension.Dynamic characteristics of rectangular aqueducts with rib and without rib,and U-shape aqueduct are respectively analyzed.The results show that,as for U-shape aqueduct,the vertical prestress and the circumferential prestress can obviously reduce the overall stiffness of the structure, but the prestressing effect does not change the order of mode of vibration.Through analyzing 6 kinds of sequence of prestressing tension for rectangular aqueduct without rib,we obtain a reasonable sequence:Firstly,prestress in the longitudinal direction is tensioned up to 40% of the maximum.Secondly,we tension the prestress in the vertical direction.Then,the rest of prestress in the longitudinal direction is tensioned.Finally,we tension the prestress in the transverse direction.This sequence of prestressing tension of rectangular aqueduct without rib can not only avoid the excessive influence of vertical prestress on the overall rigidity of the aqueduct,but also counteract the negative deflection due to gravity of the structure at early stage.Influence of this sequence of prestressing tension on mechanical properties of aqueduct is the smallest in comparison with other sequences.

Key words: characteristic parameter, aqueduct, prestress, tension sequence, dynamic properties