Calculation And Monitoring Of The Cable Hoisting System Of The Longmen Bridge

Current common cable hoisting construction method is a common bridge construction methods. In the valley of the complex terrain,large machinery and equipment can’t approach and cable hoisting method can be used for hoisting construction of precast arch ring,Then connect the precast segments to form the overall, eventually forming the main arch ring. This method is easy to operate, easy to master, construction is convenient, simple process, low cost, safety, etc. the operation safety of the cable hoisting system directly influences the construction safety and construction period, this paper to ensure the cable hoisting system can safely and smoothly run in the construction, the main research work is as follows:1、To calculate the cable in cable hoisting system. Calculation of the main cable, presuppose that empty and heavy rope across the biggest sag, following the corresponding Charpy to calculate and approve safety factor.The method of the accounting the work cable is the same to the main cable. Accounting the lifting cable is calculation the running head tension F and checking the safety factor,and calculating each lifting hoist rope capacity and the length of the single lifting rope, finally,calculating the imbalance load on tower caused by the sling load. firstly,calculating the maximum traction,and then checking the safety factor of the, and then checking the length of the pulling cable on each side, Finally calculating the pulling cable force acts on the cable tower. Through calculation, cable hoisting system of all kinds of rope can satisfy the construction process is the use of safety and applicability. Through calculation, all kinds of rope of the cable hoisting system can be safetly used in construction.calculating the arch box stress and buckling stress on the installation phase.2、To calculate the anchor and tower foundation of the cable hoisting system. Calculating the stability of the pulling force about the anchor block. Calculating the tower foundation through the finite element model is established by using SAP2000, Comparing the calculation results which is each working condition of the arch box hoisting, calculating the foundation stress under the most unfavorable conditions. Through calculation, the anchor can run normally throughout the cable hoisting construction.3、In the actual construction of cable hoisting system, under the different load condition monitoring, the different load condition was70%,100%and70%respectively hang retry crane monitoring. The main content of the observation, the displacement on the top of the tower under different load condition observation, tower foundation settlement monitoring, Key bar stress monitoring, main cable sag observation and main cable force monitoring. Through the test monitoring, cable hoisting system can run security.