CIVIC TOWER GOULBURN ST, SYDNEY The original concept for the tower floor plate design was for a post- tensioned concrete sla and eam arrangement with an overall depth of 420mm to cater for the live load of 4kPa, plus an additional 1kPa for superimposed live load and a 10kPa live loading for compactus zones. Involving NPCAA memer Ultrafloor ® in the planning stage, the engineering design team were ale to ring aout savings in construction time and floor zone thickness. The programming challenge of the Civic Tower required a flooring system with a greater spanning capaility, ut with the speed of erection associated with precast concrete. This led to the selection of the company’s metaldeck system, tested earlier at Melourne University for structural integrity and resonant frequency. The rectangular eams had protruding shear reinforcement ties to ensure proper engagement etween the topping and precast concrete, and provide longitudinal shear capacity. Spacing the eams typically at 1.7m, spanning up to 11m, and ridging the gaps with a 0.75mm gauge ried metal sheet, the floor thickness was reduced to 370mm. This is made up of 250mm deep precast eams and a 120mm concrete topping thickness. RF82 mesh is placed over the deck efore the 32MPa grade concrete is placed in-situ. The ends of the eams are tied into the jump- formed external elements. One row of temporary midspan props was the only other support. Up to 1000m 2 of metaldeck floor needed to e installed per day to keep up with the tight construction programme. Peter Whyte, Grocon’s Project Manager added that “this flooring system worked hand in glove with the two jumpform systems, to cast the core and exterior walls of the uilding. A day after casting the external and internal core, the jumpform was raised to its next position and construction of the 1000m 2 floor sla egan. The sla was poured some 4 days later, and the next day the window units, On the corner of Castlereagh and Goulburn streets in the Sydney CBD, Grocon was developer and builder of Sydney’s Masonic Centre. The new tower is supported by a complex transfer structure comprising massive inclined concrete-filled fabricated steel tubes and post-tensioned concrete tie beams forming the base floor of the tower. The whole tower of some 1000m 2 floor plate is founded upon the existing Masonic lift core of only 200m 2 . Head Contractor: Grocon Structural Engineer: Connell Wagner Architect: PTW Architects Ultrafloor Footprint: 30,000m 2 Address: Cnr Goulurn & Castlereagh St’s, Sydney Construction Type: Office Tower – Jump formed external walls and core walls using Ultrafloor’s Megaeam spanning 11m with metal deck infill etween eams at 1700mm c/c