North America’s forthcoming tallest reinforced concrete building continues to set milestones in high performance mix usage and yield data on improved
North America’s forthcoming tallest reinforced concrete building continues to set milestones in high performance mix usage and yield data on improved self consolidating mix designs and placing methods. The Trump International Hotel and Tower in Chicago has surpassed the 30th level and is pacing a mid-2008 top out, with initial occupancy in 2009. At 1,134 ft. (plus spire), it will be the new height record holder for a concrete building in the Western Hemisphere, besting Chicago’s 972-ft. tall 311 South Wacker Drive building Û about one mile away from Trump.
In June, concrete contractor McHugh Construction and ready mixed supplier Prairie Materials completed a two-level (28-29th floors, mechanical) outrigger/wall-beam structure transitioning the tower from its main footprint (Ground-27th floor) to a smaller plate (30-49th floors). At 17.5 ft. deep and up to 66 in. wide, the outrigger is engineered to tie the building’s core and perimeter columns. Its heavily congested rebar saw Chicago-based architect and engineer, Skidmore, Owings & Merrill, specify a self-consolidating concrete mix with 16,000-psi design strength.
By Concrete Products records, the outrigger placement represents a new strength record for commercial SCC. It follows a highly successful call Skidmore, Owings & Merrill made for a 10-ft.-thick mat foundation supporting the tower’s core. Placed over a 30-hour window in September 2005, the mat incorporated a 10,000-psi design strength mix and marked what was then the largest SCC placement to date in North America.