For the construction of a new steel mill, Nucor Corporation was planning to stick-build the mill’s entire furnace. Mammoet had been asked to install the furnace’s main reactor onto its foundation. After assessing the situation, Mammoet suggested an alternative, much quicker approach: building the furnace modularly and then assembling it on site. While stick-building the furnace would take about a year, building it in modules would take only half that time. Nucor gave Mammoet the green light, and in doing so brought forward its production-ready date by six months.
MODULAR CONSTRUCTION BRINGS A STEEL MILL IN BUSINESS SIX MONTHS SOONER.
Construction was just one part of Mammoet’s task in the Nucor project. Transporting parts for the facility, including the main reactor, was Mammoet’s second main responsibility. The most challenging task proved to be the transport of the 56-meter tall, 1,100-ton reactor. On its way to the construction site, the reactor had to cross a levee as well as a river road that were both too unstable to carry the heavy load. Going around them would delay the transport and installation by several days, and therefore wasn’t an option.
Mammoet decided to build a bridge over the levee and river road. Further to this, Mammoet designed a 250-meter temporary road over a wetland area between the river and the bridge. While the reactor was en route to the mill, the base of the furnace was being stick-built at the construction site to a height of 49 meters. At the same time, five modules were constructed around a PTC crane. One of the largest cranes in the 5,000-ton class, the PTC 140 DS was be able to reach all modules from one central position and lift them into place – a much faster solution than using a gantry system as was proposed in Nucor’s original plan. Once the base was finished, Mammoet raised the reactor 67 meters and installed it into the furnace structure after which the five other modules were fitted over the reactor – all within a single week.
By designing the temporary road and building the bridge, transporting the reactor from the riverbank to the construction site took only three hours instead of several days, and without causing any damage to the environment. Thanks to a detailed engineering plan and thorough on-site supervision, installation of the reactor was completed in just three hours. Overall, Mammoet’s alternate plan trimmed the total construction schedule by as much as six months, providing Nucor with an extra six months of valuable uptime.