Installation Methods for Gantry Cranes
According to the structural composition of the gantry crane, the main beam needs to be hoisted as a whole, which is the largest component and key factor in the gantry crane installation project.
Gantry cranes are generally installed in a bottom-up method. First, the walking trolley and the lower beam are installed on the track. Then install the flexible and rigid legs on both sides respectively. And use temporary wind rope to stabilize the outriggers. The truss-type main beam needs to be assembled on site first. During installation, the cart walking track can be used as a horizontal reference. And the assembled main beam can be placed horizontally on the track.
When assembling the main beam, attention should be paid to maintaining the upper camber of its midspan to compensate for the sinking deflection. The conventional installation method of the main beam is to use other lifting equipment to lift the main beam horizontally.
Before hoisting the main girder, the position of its center of gravity must be accurately calculated. Because the position and load of the auxiliary crane's hoisting point are determined accordingly. Specifically, the load should be distributed reasonably according to the lifting performance of the auxiliary crane. The lifting load of each auxiliary crane shall not exceed 80% of its allowable load.
For example, according to the situation of the main beam of the 40t/40m gantry crane, two 50t cranes are selected for lifting, which can meet the lifting requirements. When using a single crane, it is necessary to choose a crane with a weight of 100t, which has a large tonnage but is not economical.
The weight of the main beam is relatively large. Under normal conditions, the lifting mechanism, lifting trolley, driver’s cab and other components need to be installed behind the main beam.