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Concrete Fiber Solutions, Prairie Material ‘wired’ into mesh alternative

Concrete Fiber Solutions (CFS), along with Prairie Material and Goebel Forming, recently completed a massive flooring installation at the 110 N. Wacker project in Chicago, utilizing steel fiber reinforced concrete in place of traditional wire mesh. The high-rise features composite metal deck floors reinforced with 25 lbs./yd. of CFS 150-5 fibers in lightweight concrete mixes. The fiber substitution contributed to increased worker safety and floor-finishing efficiency.

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Dosed at 25 lbs./yd., the 1.5-in. CFS 150-5 fibers suit composite decks like those up and down the 110 N. Wacker tower.
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The 110 N. Wacker tower is the latest in a wave of developments along the Chicago River, and another major contract for Prairie Material, whose nearby Yard 32 has shouldered the bulk of structural concrete in downtown Chicago.
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Engineers on the 110 N. Wacker tower referenced an International Building Code 2015 provision allowing substitution of welded wire fabric with steel fibers for temperature and shrinkage cracking control. Exercising that option saved time and labor, and exposed floor crews to fewer tripping hazards than they might normally encounter in composite deck work.
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Steel fiber was specified by the engineer over wire mesh for its ability to better control cracking and therefore improve performance and finish. Unlike welded wire mesh or rebar, which are located in a single plane and therefore allow cracks to grow until they meet this plane, steel fibers are distributed uniformly throughout the concrete matrix to meet micro cracks where they originate. The use of CFS steel fibers at 110 N. Wacker was made possible by International Building Code 2015 adopting SDIC-2011, allowing for the use of steel fibers in place of welded wire fabric to control temperature and shrinkage cracking in composite metal deck applications.

Wire mesh is not only a major job site tripping hazard, CFS officials contend, but also difficult to install and keep in place in a way that effectively reinforces the concrete. Using fibers saved time and money on the Chicago job by eliminating the labor and crane costs associated with welded mesh transfer and placement.

“Fiber-reinforced concrete can be poured and finished in the time it takes to set wire mesh on deck,” says CFS Midwest Sales Manager Matthew Norman. “We’re proud to have helped supply Prairie Material and Goebel Forming with a concrete flooring solution that offered a more efficient installation and superior performance long-term.” Norman has 15 years of experience in the concrete industry. He obtained a Civil Engineering degree from Purdue University where his major field of study was Reinforced Concrete Design.

The 110 N. Wacker job reflects an ever-increasing trend in the use of steel fibers over antiquated reinforcement methods, he adds. In 2019, the company’s 1- and 1.5-in. fibers were used in more than 5 million square feet of flooring and slabs across 11 states and as far away as Ciudad Juarez, Mexico. While engineers and concrete contractors across all industries are embracing steel fiber reinforcement, particular growth is evident in commercial warehouses, distribution centers, cold storage and food processing facilities—all conditions where heavy equipment and foot traffic benefit significantly from the superior crack control and increased joint spacing fibers afford.

Manufactured in Chicago, CFS Fibers are free from rust, oil and other contaminants, and designed to meet or exceed the requirements of ASTM A820 Standard Specification for Steel Fibers for Fiber-Reinforced Concrete. The 150-5 fibers are 1.5 in. long with an aspect ratio of 38, and deformed per the ASTM A820 specification. CFS 100-2 fibers are 1.0 in. long with an aspect ratio of 43, deformed per ASTM A820, and well suited to slab-on-grade specifications.

In addition to fibers for concrete slab and composite concrete-steel deck applications, CFS has developed ProSlab, offering flat, smooth, and virtually curl-free floors with fewer joints by using wideslab technology. The time-tested construction method entails designing and constructing a slab on grade in which individual panels extend a minimum of 50 feet in at least one dimension. Wideslab construction relies on methods other than joints to control cracks and curling. CFS ProSlab uses single course installation giving the slab continuity from “top to bottom.” — Concrete Fiber Solutions, Buffalo Grove, Ill., 847/212-0268; www.concretefibersolutions.com