The Control Cable In The Pc Cable-stayed Bridge During Construction

Stayed-cable is one of the main structural members of cable-stayed bridge, and it is also the important and difficult part in the construction control. As one of the most popular modern stayed-cable, the parallel strand stayed-cable should have increasing application because of its characteristic and economization. So, it is necessary to study parallel strand stayed-cable overall. Meanwhile, the formwork placing elevation is influenced by several factors, especially the influences caused by mid cable force and preceding fulcrum traveling carriage cannot be ignored.Based on the construction of Wuhekou Bridge, some important issues about stayed-cable which arise in the process of construction control of PC cable-stayed bridges are studied. The development and characteristics of PC cable-stayed bridge, and the traits and thinking of the construction control of cable-stayed bridges are introduced, as well as the control methods are analyzed. It is concluded that the adaptive control system is one of the best control way at present. The content of construction control is introduced and the influencing factors in the process of construction control are analyzed. A detailed introduction to the construction ways and technics of Parallel strand stayed-cable is given in this paper. Aimed at the construction methods, the constructional length and tension control of the strand stayed-cable are analyzed, which making the tensions in the strand stayed-cables keep uniformity and ensuring the construction go on wheels. The exact formula of the mid cable force in the construction process through calculating the influencing factors of the mid force is put forward. Considering the characteristic of preceding fulcrum traveling carriage, the influence of mid cable force on the formwork placing elevation of traveling carriage is explained at the same time. The modified formula of the setting levels of the main beam is concluded, which educes the exact setting elevation of the main beam construction. Moreover, aiming at the uncertainty of formwork placing elevation aroused by the traditional preceding fulcrum traveling carriage in construction, a new conception is suggested.While the above-mentioned analyses and calculation methods was applied to the Wukouhe Bridge, it was proved that the cable tension and linearity of the project were control successfully. It is significant to improve the development of parallel strand stayed-cable. The exact control of formwork placing elevation makes the bridge...