South Korea-based contractor Doosan Heavy Industries & Construction used a Manitowoc MLC650 lattice boom crawler crane to carry out heavy lifting operations at a congested railway station work site. The station in Daegu City is 300 kilometres from Seoul and part of an expansion project being managed by the South Korean government's rail department.
The site’s limited land area offered little space for large cranes to operate, let alone the additional buffer required for assembly and dismantling. The MLC650 was used to lift 55 tonne pre-cast concrete sections and move them to designated areas with precision, the company said.
The crane’s MLC650's Variable Position Counterweight (VPC) is credited for its increased capacity for heavy lifts without traditional counterweight configurations, the company said, as well as easy navigation on congested job sites. Less ground preparation, less space and less counterweight are all features of the VPC. It eliminates the need to stack or unstack counterweights after or during a lift.
For the railway station job, the MLC650 was configured with 68 metres of main boom and the VPC-Max attachment which uses VPC technology to offer improved capacity and reach. In this set-up, the crane was used to service a load of 62 tonnes, positioning it at a radius of 50 m. This was still possible despite local site stipulations requiring that the crane lift at only 70 percent of its rated capacity.
The closest alternative choice of crane for this project required a small hill - 10 m x 10 m x 40 m - to be levelled for it to be positioned, and this was also a further 10 m away from the site. Such a distance also immediately translated to a 25 % decrease in load capacity, the company explained.