PRODUCTS > FLEX-JOIST™
Flex-Joist™ tension-controlled open web steel joist design gives building owners and specifiers the option of consistently higher steel joist performance at an affordable cost.
Laboratory testing has consistently demonstrated the Flex-Joist™ design to exceed standard steel joist design for strength, reliability and ductility.
31% higher reliability index
Standard SJI joists are designed based on procedures derived from the American Institute of Steel Construction (AISC) design specifications. AISC states that their design specifications result in an average member reliability index of β = 2.6, where β is the ratio of the standard deviation to the mean. Flex-Joist™ has been demonstrated to have a system reliability index of β = 3.4, or 31% higher than the industry standard.
By selectively increasing the size of the weakest components without decreasing the size of the strongest components, the strength of a Flex-Joist™ is substantially increased at an affordable cost.
129% higher ductility
The Flex-Joist™ design is based on limit states control, so it has a much higher probability of achieving a ductile tensile yielding limit state that is characterized by slow collapse, with large inelastic deformations and inelastic reserve capacity. This very ductile behavior gives sensory warning of impending collapse, allowing more time for evacuation and response.
Optimized safety sensoring
The Flex-Joist™ is ideally suited for the optional, post-erection installation of electronic sensoring and alarms to establish an early, roof overload warning system. The bottom chord and end webs of a Flex-Joist™ will be highly stressed prior to collapse and the location of sensors along these components can readily be installed by a third party provider.
Disclaimer: No joist will withstand sudden and catastrophic impact forces that exceed system capability. Flex-Joist™ design offers probability of high ductility and time delay under static gravity overload conditions.
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