Precast Prestressed Hollowcore Planking
STRONGER... FASTER... BETTER!
Mack Industries is known for its reputation in precast concrete. For over 75 years, the Company has been leading the way with innovative precast concrete products. In 2004, Mack added prestressed hollowcore planking to its large product offering, making the move into both prestressed concrete and structural concrete for residential, commercial and industrial building construction. Put Mack's reputation for Quality and Service to work for you !
Prestressed concrete has been used for over 30 years in commercial and highway construction projects where concrete must span long distances between supporting structures. Precast, Prestressed Hollowcore Planking is used primarily as a floor, roof, mezzanine area or tilt-up wall panel in commercial, institutional and industrial buildings. It also has found widespread application in residential construction as maintenance-free porches, decks, wine cellars, safe rooms and garage floors where living space beneath the garage is desired. Able to clear-span over 40 feet using less than a foot of vertical height, the product is a better substitute over traditional steel building methods in many designs. Once delivered to the jobsite, the product is quickly set in place by employees using a crane and connected to a building's masonry or steel structure.
How It Works
Low-slump concrete is continuously placed on a 500-ft. long casting bed utilizing a slip-forming machine. The concrete is consolidated around high-tensile strength steel prestressing strands that have been tensioned to over 31,000 lbs. each. More strands placed in the product allows higher plank strengths and loading for a given span. The cores and keyways on the side are formed as the slip-forming machine moves down the casting bed. After forming, block-outs, weld plates and other embedded items may be added to the product.
After curing, the bed is detensioned; imparting additional compressive strength to the product from the release of the prestressing strands. The product is then cut to length and width per specifications, removed from the bed and allowed to cure to full strength prior to shipment. Once shipped to the jobsite, a crane lifts each piece into place. It is then connected to the building by welding when on steel or by grouted rebar connection in the case of masonry or concrete. All precast-to-precast joints are then grouted solid to provide a unitary structure. Often a thin, self-leveling compound or composite structural concrete topping is then applied.
The Mack Advantage
Mack is a Precast Prestressed Concrete Institute (PCI) certified producer-member; giving you the assurance the highest quality levels are attained.
Mack's use of recycled content can contribute up to 2 points toward the U.S. Green Building Councils' Leadership in Energy and Environmental Design (LEED) Green Building Rating SystemTM for certification in sustainable design. Superior design flexibility; allowing for curves, angles, cantilevered balconies, penetrations and large openings.
8" thick hollowcore can support 100 psf superimposed service loads on spans over 28 feet, while 10" thick product can support 100 psf superimposed service loads on spans over 33 feet.
A composite concrete structural topping can be applied to increase product strength.Mack utilizes a 5000 psi min. mix design that routinely provides 28-day strengths of over 7500 psi.
Mack's 8'-4" wide plank installs at more than twice the competitors' square footage per crane pick. Our erection crews can confidently install over 8000 square feet of planking per 8-hr day.
Mack's standard lifting system allows the use of hooks on 4-way slings, eliminating the need for slings and to "pry" and "nudge" pieces into place.Installation is not subject to common weather and site delays.
Mack's use of welded wire fabric in the top surface provides a resistance to the prestressing strand, thus resulting in a product with significantly less camber than our competitors'.
Mack's slip-forming process creates a superior paint-ready finish to the bottom of exposed planks.Mack's 8'-4" wide planks means less time is required for caulking and grouting because there are less seams.
Installs faster than steel and concrete "pan" floors and can reduce building height and associated costs.
Standard product provides 2-hr. Underwriter's Laboratories fire rating.