Support Systems

Framing technologies developed in Japan and Australia likely to impact both low-rise and high-rise construction for decades to come are gaining footing throughout the global construction community.

Japan’s Takenaka Corporation has developed the “Super Flex Wall”, a method of structural framing used in super high-rise buildings and designed to act as a malleable shock absorber in the event of catastrophic natural disasters such as earthquakes.

On a smaller, yet no less-important scale, LiteSteelTM Beam (LSB) originated in Australia is proving to be an effective cost-saving method in both the residential and light nonresidential sectors. Lighter and easier to use than traditional steel, LSB is stronger than Laminated Veneer Lumber and can be applied in numerous ways ranging from floor and bearer beams to roof and ridge beams and fascia.

SUPER FLEX WALL
The University of Purdue highlighted this revolutionary system on its Emerging Construction Technologies website earlier this year. With natural disasters ravaging the global built environment and buildings growing taller every year, the need for technology that is resistant to seismic activity in an urban setting is readily apparent.

The Takenaka Corporation has successfully employed the “Super Flex Wall” system on a number of projects, including the “Akasaka Tower Residence top of the Hill” in Tokyo; the “City Tower Nishi-Umeda” in Osaka; and the “AMEX Ohori Tower” in Fukuoka City.

Seismic resistance is a key component to any high-rise development. The structural framework necessary to ensure integrity can often be challenging but the “Super Flex Wall” system aims to achieve that by controlling bending deformation of the building during any prolonged period of severe shaking.

“The ‘Super Flex Wall’ is a structural frame method … used in combination with a core wall (the earthquake-resistant reinforced concrete wall penetrating through the center of the building from the lower part to the top floor) and a structural control method or with a base-isolation method. Part of the structure is cantilevered from the central core along the periphery of the building,” the Purdue web site explains.

Crucial to the system is the use of outrigger beams that have larger cross-sections than normal beams and are installed in intermediate floors and in the top floor. Bending is also controlled by the use of wall beams that are the height of one floor layer and are also installed in the upper floors. Placing the core wall in the center of the building allows for wider variety of surprisingly spacious floor plans throughout the housing areas.

LITESTEEL™ BEAM
More than six years of research and development went into the creation of LSB by LiteSteel Technologies, a subsidiary of Australian steel giant OneSteel Group. The Department of Civil Engineering at the University of Sydney and The Faculty of Built Environment and Engineering at the Queensland University of Technology both conducted rigorous beta testing before the product went to market.

The LiteSteel Technologies website proclaims: “Lite Steel is a revolutionary new product that was developed in response to the demand for a light structural beam with the strength of steel but the installation workability normally associated with wood products.”

An innovative cold forming manufacturing process gives LSB a unique profile with a flat, thin web and two hollow flanges that provide maximum load-carrying capacity and torsional rigidity associated with hot rolled steel sections. LSB products have achieved a Code Compliance Research Report (CCRR#0123) against the 2006 and 2009 International Building Code, and the 2006 and 2009 International Residential Code.

Several factors make LSB – formed from a single strip of DuoSteel (380/450 grade) – more attractive than equivalent hot-rolled steel or engineered wood beams. LSB is on average 40 percent lighter than both, eliminating the need for and cost of a crane since it can be carried like lumber.

Ease of use is another attractive feature. LSB is compatible with a range of standard fittings, can be cut with a handheld circular saw, drilled with professional drill guns, nailed with a pneumatic nail gun and, when necessary, welded using manual metal, gas metal or flux cores arc welding.

The use of LSB figures prominently in the design and construction of a raised four-story hostel built at the “Big Dig Site” in the historic precinct of Sydney known as The Rocks. The site contains physical evidence of Australia’s first European settlement, including the remains of more than 30 buildings. Engineers from LiteSteel Technologies worked hand in hand with builder Built Pty Ltd and engineer Taylor Thomson Whitting throughout the project to minimize points of ground contact with the archeological site.