The construction of bridges is a highly skilled process. In order for the design of a bridge to be carried out, special equipment must be used to complete the project due to the size and weight of the materials. According to the Transportation Research Board website, international construction companies work together to design, build, and supply the correct and most recent equipment for bridge construction.
According to the NRS Bridge Construction website, the Norwegian-based international construction company has worked with other construction engineers worldwide to develop the Bridgebuilder machine. The machine is lightweight, easy to assemble, and moves on fixed rails. The Bridgebuilder is used to move materials and construct the frames of concrete bridges. The machine is designed to be able to move and support anywhere from 100 to 400 tons of bridge building materials.
Gantry cranes are used to cost-effectively erect and build segmented bridges. The NRS website explains that gantries are built either as overhead or under-slung machines in order to meet specific bridge construction needs. Gantry cranes are simply very large cranes that are used to maneuver and quickly build a bridge one beam at a time. The under-slung gantries operate by using hydraulic cylinders to support the various bridge segments. The overhead gantries suspend and move segments through the use of specifically-designed tension bars.
A beam launcher is used to position and install pre-cast concrete beams for bridges that are being built over a body of water or viaducts. When building a bridge that is crossing unsteady ground or has high piers, the beam launcher is used to position the beams correctly and safely. The two kinds of beam launchers include single box and twin-truss type. The single box beam launcher is lightweight and used for erecting pre-cast beams on tight horizontal alignments. The twin-truss beam launcher is used worldwide for constructing large scale bridges.
A straddle carrier is used in place of a gantry crane when heavy materials must be lifted at casting yards, factories, storage areas, ports and marinas. The NRS website explains that gantry cranes are attached to fixed rails, while straddle carriers are built on tires with motorized wheels to make construction and material mobilization possible. A straddle carrier operates by using hydraulic systems, winches, ropes, and electric and hydraulic motors.