The Double Girder Semi-Gantry Crane is a hybrid lifting solution that combines the strength of a double-girder gantry crane with the space-efficiency of an overhead crane. Unlike a full gantry crane that requires support structures on both sides, this design features one end supported by a rigid leg that travels on a ground-level rail, while the opposite end carriage rides on an existing building runway beam, wall bracket, or elevated structure. This asymmetric configuration eliminates the need for a second ground rail or foundation, significantly reducing civil works cost and installation time.

The crane is built around two parallel box-section main girders that deliver the torsional rigidity, hook height, and lifting capacity of a full double-girder overhead crane. The twin-girder design means the hoist trolley sits on top of the girders rather than below them, maximizing available hook height within the same structural envelope. A full-length maintenance walkway platform runs along both girders as standard, providing safe, unrestricted access to every hoisting and travel mechanism.

1. Indoor–Outdoor Material Handling in Factories
This crane bridges the gap between indoor production areas and outdoor storage or dispatch zones. With one rail mounted on the building's column line and the other on a floor‑level track outside, it eliminates the need for a full gantry structure, saving both steel and installation cost. It is particularly effective in steel service centres, automotive stamping plants, and heavy machinery factories, where it moves coils, billets, or finished components directly from the shop floor to trucks or railway wagons, reducing intermediate transport steps and improving throughput.

2. Shipyard Sub‑Assembly and Block Turning
In shipbuilding, large prefabricated sections (blocks) must be lifted, rotated, and positioned for welding. The double‑girder semi‑gantry offers a long span and high capacity (often over 100 tonnes) while occupying less footprint than a full portal crane. Its cantilevered side can extend over the water edge, allowing blocks to be lowered directly into dry docks. The twin‑girder design ensures exceptional rigidity, which is critical for precise alignment during block turning and fitting, minimising rework and shortening berth occupancy time.

3. Steel Coil, Plate and Pipe Storage Yards
These yards typically have limited headroom due to overhead conveyor systems or roof trusses. The semi‑gantry configuration adapts perfectly: the high rail runs along the building structure, while the low rail is embedded at floor level, maximising the clear lifting height under the roof. Double girders provide the strength needed for heavy, uneven loads such as hot‑rolled coils or long pipes, while the crane’s anti‑sway control and variable frequency drives ensure smooth handling during high‑density stacking and retrieval, reducing product damage and improving inventory turnover.

4. Precast Concrete Production Facilities
In precast plants, heavy moulds, reinforcement cages, and finished concrete elements (beams, wall panels, hollow‑core slabs) require constant movement between casting beds, curing areas, and loading bays. The semi‑gantry crane’s floor‑rail side can run freely along the production aisle, while its upper rail hooks onto the factory's existing steel columns – making installation quick and cost‑effective. The double‑girder construction provides the necessary stability for tandem lifting (two hooks) and allows the crane to travel with heavy loads at high speeds without excessive deflection, ensuring safe and efficient 24/7 production cycles.