Tackling road weight restrictions

Like many German crane service providers, Colonia Spezialfahrzeuge, based in Cologne, is faced with the challenge of obtaining transport permits for its mobile cranes, some weighing significantly more than 60t. This is because many roads and bridges in North Rhine-Westphalia do not permit heavy vehicles, often resulting in major detours during transport to construction sites, causing time delays and costs.

To tackle this issue, Colonia worked with its long-term partner, Manitowoc, to create a new, high-performance transport system, the first tests of which have already been completed.

The new crane configuration is based on the six-axle Grove GMK6300L-1. With its 80m main boom and at a radius of 28m, the crane offers a lifting capacity of 14t, ideal for the sort of jobs Colonia is often required to do.

In addition to an overall reduction in operating weight, Colonia's requirements included a hydraulic boom removal system on the mobile crane for rapid assembly and disassembly of the main boom and lift cylinder. It also required the construction of a transport system that didn’t require an assist crane for assembly and disassembly.

In response, Manitowoc produced a crane that perfectly matched Colonia’s requirements. The base unit can be equipped with an easily removable rear outrigger box. Hydraulic rigging cylinders on the chassis can be operated from the carrier, and hydraulic and electrical quick couplings enable rapid and efficient installation and removal of the outrigger box in less than ten minutes.

The hydraulic boom removal system is available as an option and Manitowoc already supplies all-terrain cranes equipped with the system to the North American market, to accommodate local roading regulations.

The assembly and transport unit for the main boom and lift cylinder was redesigned to eliminate lift cylinder overhang while transporting the crane on the road. Using this design configuration, the boom and lift cylinder are moved directly from the crane to a separate transport trailer on a set of sliding rails. The boom and cylinder are removed and reinstalled precisely without the need of a separate assist crane.

The first tests with the modified crane have proven extremely successful. The main boom and lift cylinder move out of the upper structure of the crane with the semi-trailer's sliding frame with exacting precision, avoiding overhang during road transport. The total weight of the semi-trailer loaded with the main boom and lift cylinder is less than 59t. By removing the boom and lift cylinder, the crane’s gross vehicle weight is reduced to under 40t, with axle weights below 7t per axle. This is also beneficial in other countries with roading restrictions, such as Norway, Canada and the USA.