MILFORD, Mass. – Barker Steel LLC, a provider of concrete reinforcing solutions based in Milford, MA, introduces the US to the Cobiax voided slab technology, which is debuting this month with the new Miami Art Museum (MAM) facility, currently under construction in Downtown Miami’s Museum Park. Cobiax is a reinforcing concrete system that utilizes 100% recycled plastic material voids incorporated with rebar and concrete to create voided slabs. This process efficiently eliminates concrete where it is not required, considerably diminishing dead weight while maintaining the flexural strength of the slab. The reduction in concrete allows for overall cost reduction, design flexibility, increased seismic performance, and environmental sustainability. 

The new Miami Art Museum, designed by Pritzker prize-winning architects Herzog & de Meuron, with executive architecture by Handel Architects, will total 200,000 square feet of programmable space, with 120,000 square feet interior, and 80,000 square feet exterior. The museum galleries will sit on an elevated platform and below a canopy, both of which will extend far beyond the museum’s walls, creating plazas and a shaded veranda. The goal of this “open-air” structure is to bring the park into the museum with panoramic views, achieved by a reduced number of columns.

In order to bring that vision into reality, structural engineering firm ARUP had to find a solution to:

•Support the structure efficiently with the least number of columns.

•Mitigate the weight associated with the slabs, which were substantially thickened to accommodate recessed lighting, the sprinkler system, and 2-1/2” cover to protect the reinforcing steel from salt spray that comes from the nearby harbor.

The answer was to use voided slab technology as part of the concrete reinforcing system. The Cobiax voids are being used in approximately 105,000 sq. ft. of the building and will displace 955 cu. yards of concrete, reducing the dead load by 3.9 million pounds, allowing the slabs to be supported with fewer columns.

In addition to solving its structural challenges, Cobiax will also contribute to sustainable design by:

•Using voids made of post-consumer and post-industrial HDPE (High-density Polyethylene) material.

•Reducing carbon emissions through the use of less concrete volume: Each cu. ft. of concrete displaced eliminates 13 lbs of CO². The total displacement of concrete in the MAM project will be 25,785 cu. ft., eliminating a total of 335,000 lbs of CO².

•Reducing transportation to job site: One truckload containing Cobiax cage modules on average replaces 6 ready mix truck trips. For the MAM project that results in approximately 80 fewer ready mix deliveries.

•Reducing the heat island effect: The mass of concrete causes it to act as a significant thermal reservoir, so steady internal temperatures are easier to maintain. This effectively helps to even out night and day temperature swings as well as seasonal effects.

The contractors and suppliers involved in the introduction of Cobiax to the American construction industry through the Miami Art Museum Project are:

•Barker Steel LLC, Milford, MA – Cobiax licensed supplier in the United States
•John Moriarty & Associates of Florida, Inc., Hollywood, FL – Construction Manager
•Reinforced Structures, Inc., Clearwater, FL – Concrete Contractor
•Titon Builders, Lake Park, FL – Rebar and Cobiax Installer
•Meredith-Springfield Associates, Inc., Ludlow, MA – Cobiax void manufacturer
•Nucor Connecticut, Wallingford, CT – Cobiax Cage fabricator

“I have to admit, when RSI first reviewed the drawings for the Miami Art Museum we were a bit thrown by all of the circles shown on the slab plan. The more we learned about the voided system and understood the function it became quite exciting….. Once we put down the first slab reinforcing and Cobiax voids we truly saw the benefits of the system and how these slabs are allowing the architects to fully create their open space gallery vision.” Brooke Madson, Project Manager, Reinforced Structures Inc.

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