Towers for underground
20 June 2019Two tower cranes, supplied by Australian heavy lifting specialist Marr Contracting, were preferred to traditional crawlers as a key phase of the Sydney Metro was completed recently.
With 16 construction sites on the opening Northwest stage alone and an overall project value of over AUD20bn, the Sydney Metro public transport project is notable for its scale and complexity. The Northwest Rapid Transit (NRT) consortium was awarded the operations, trains, and systems contract for this facet of the project. A variety of tasks included building eight new railway stations.
Marr Contracting was awarded a scope of work by NRT at the Castle Hill Station, covering installation, operation, and removal of cranes, including extensive methodologies and lift plans. A considered solution was based on crawler cranes travelling along the edge of a 200m x 30m cut-and-cover station box in order to complete the required lifts, but Marr’s luffing jib crane solution centred on both cranes sitting alongside the box and provided lifting capacity across the entire site.
Marr Contracting managing director, Simon Marr, said: “The site was congested and landlocked between two existing roads. The crawlers proposed would have placed a large surge load against the station box walls, which meant that the client would have to excavate around the box and fill in with groundworks to specific bearing pressures. The costs were excessive and would have had a major impact on the programme. Furthermore, using the crawlers would still have been a limited solution.”
He added: “The project will serve as a blueprint for future mega projects as decision makers recognise the benefits of decongested sites. Our solution facilitated lifting of loads from outside the project’s boundaries, which further decluttered the site and led to additional time and economic savings—not to mention a safer work environment.”
The cranes provided were both the result of design collaboration between Marr and manufacturer Favelle Favco: a 330t capacity M2480D with 90m boom and a 200t capacity M1680D with 62m boom. They lifted a variety of loads, including pre-cast beams, columns and panels weighing up to 60t; in addition to site machinery, such as earth-moving equipment, mobile cranes, concrete, reinforcing steel, and general construction materials required for a tunnels project of such magnitude.
