Fluted, exposed-concrete columns are key to an elliptical, 42-story, 147-unit luxury condominium tower known as ‘The Century,’ rising on the Avenue of the Stars in Los Angeles’ Beverly Hills district
Fluted, exposed-concrete columns are key to an elliptical, 42-story, 147-unit luxury condominium tower known as ÎThe Century,Ì rising on the Avenue of the Stars in Los Angeles’ Beverly Hills district. Customized fiber-reinforced polymer (FRP) fluted round column forms (FRCF) manufactured by Independence, Kan.-based Molded Fiber Glass Construction Products (MFG-CP) were used to create the 250-plus columns, whose fluted design features what project principals describe as a lavishly smooth finish.
Designed by New York City’s Robert A.M. Stern Architects LLP, the 885,000-sq.-ft. Century Project was started in June 2007 and is slated for December 2008 completion. Supporting the tower is an interior moment-frame atop a 7,100-yd. concrete mat foundation. The exterior skin combines stone cladding and sculptured precast supplied by Clark Pacific, West Sacramento, Calif.
The project’s architectural firm of record HKS, Inc., Dallas, enlisted concrete contractor Webcor Concrete of San Mateo, Calif., to secure a formwork supplier for fluted-column fabrication. After ruling out steel and plastic alternatives, Webcor contracted MFG-CP, which specializes in a range of custom and standard fiberglass-reinforced thermo-set composite column forms. Accordingly, the company custom built 15 FRP/FRCFs, in addition to a multitude of standard FRP/RCFs for distribution throughout the tower.
MFG-CP’s goal was to create a distinctive fluted form offering stability during the pour equal to the columns’ 13-ft. scale, as well as flexibility, plus a smooth finish. Thus, a four-piece FRCF design was selected to optimize production, delivery, on-site assembly and pour/strip time. MFG-CP Engineering Manager Eric Brace notes, Using a four-piece form, rather than a two-piece, allowed stripping in pieces during production to ensure the smoother, luxurious finish specifications required.
Upon design approval, MFG-CP produced the forms comprising a chopped-strand mat of 24-oz. woven roving in a sandwich configuration, constructed in quarter sections to facilitate stripping from the mold and the ensuing concrete pour/peal process. The production leveraged a spray-up/open-mold method (with mold-release pretreatment) involving simultaneous placement of the chopped-strand mat on the cavity mold and pouring of the catalyst resin for even flow.
Although created in quarter sections, the FRCFs were delivered as 15 full forms with four seams and 9/16-in. lip-holes to accommodate _-in. coil bolts during assembly. Their composite properties rendered the forms corrosion resistant and reusable for future projects.
Following FRCF assembly, standard rebar installation, and implementation of base specifications, approximately three yards of self-consolidating concrete were placed for each column in a standard monolithic-pour sequence. Catalina Pacific Concrete supplied ready mixed for the project from its Azusa, Calif., plant. Reports Webcor Senior Superintendent Ryan Isbell, To date, construction is meeting the aggressive six-day cycle [one floor every six days], as the fluted forms are an easy pour, requiring approximately two to four minutes per column.
Adds HKS architect Patrick Treadway, The tower’s fluted concrete columns were more cost-efficient than the originally conceived precast or stone options, and they provided a practical alternative in terms of time, design and efficiency.