CEE498
Lisheng Yang
Gantry Crane
Gantry crane is the major form of heavy lifting crane which can lift more than 1000 tons’ load. It is very similar to overhead crane used in industrial workshops, except that the crane girder is supported by a movable gantry rather than structures on the wall or ceiling of the workshop. So this kind of crane can be used in outdoor situations and can cover large lifting area as well as satisfying various requirements of lifting heights. The invention of gantry crane stems from quay cargo transportation, and one of the main gantry crane types today is the container crane used at harbor. In construction industry, gantry cranes are used primarily in the lifting operation of giant components like the water gate of hydropower stations. It is especially efficient in handling regular lifting requirements around a relatively fixed region, for instance the shaft of shielded tunneling.
Classification
Based on the shape of the gantry frame and the cantilevers of the main bridge girder, gantry cranes can be divided into four major types 1) full gantry crane; 2) semi-gantry crane; 3) double-cantilevered gantry crane; 4) single-cantilevered gantry crane. Based on the moving mechanism of gantries, they can be further divided into fixed gantry crane， rail-track gantry crane and rubber tyred gantry crane.
Constitution
A typical gantry crane is made up of one major bridge and two supporting legs. The bridge is placed on top of the legs and can be cantilevered at either or both sides. The hoist is installed on the bridge, and it can be mounted on a rail supported by the bridge or directly suspended under the bridge, or placed between the beams in the case of double-beam bridge.
Manufacturers
In America, gantry crane manufacturers mostly specialize in light weight cranes and overhead cranes used in workshops.
As for heavy-load crane, there are some Chinese manufacturers who have constructed some of the world's biggest gantry cranes. Prominent companies include ZPMC and SANY.
Bridge Girder Erection Machine (BGEM)
A major variant of gantry crane is the bridge girder launcher, also called bridge erection machine. This type of machine is used to place bridge girder on the bridge piers. The biggest distinction of bridge erection machine from typical gantry cranes is its moving mechanism.
Case Study
Here are three representative case studies of gantry crane's application in construction industry. They embrace application cases in building construction, infrastructure construction and hydraulic dam construction. These studies provide some valuable perspectives of what gantry cranes can do in construction operations.