USFB® - ULTRA SHALLOW FLOOR BEAM
The need for the structural steelwork industry to develop an economical ‘flat-slab’ flooring system, led Kloeckner Metals UK | Westok to develop the patented and innovative USFB® – Ultra Shallow Floor Beam. The beam has been successfully utilised in the UK, Ireland and further afield since 2006 across a diverse range of sectors.
There is no ‘standard’ USFB®. As the beam is available in increments of 1mm depth and does not require the costly provision of additional plates or angle sections to be welded to the beam to provide an outstand element, the USFB® is perhaps the most flexible, practical and cost-efficient approach to achieving a structural steelwork up-stand beam on the market.
STRUCTURE
The beam comprises a shallow and highly asymmetric Westok cellular beam, designed and detailed to permit the floor to sit on the outstand bottom flange, with great freedom to run services below the soffit of the floor.
The slab typically comprises traditional metal decks, longer span deeper metal decks, or the range of precast concrete flooring products on the market.
STANDARDS
There is no standard USFB® size or depth. Each beam is designed to meet the requirements of the application. The cells can be used to provide free passage for reinforcement for the provision of simple, yet robust disproportionate collapse detailing.
PLUG COMPOSITE ACTION
Plug Composite Action can be mobilised, which has been demonstrated using full-scale laboratory testing to further enhance the capacity of the section, and this additional enhancement has been applied to our USFB software.
To mobilise Plug Composite Action, the following detailing should be adopted:
- Metal deck slabs: concrete cast level with, or above, the top flange
- Precast units generally: minimum 50mm topping level with, or above the top flange
- Hollowcore units: Every 2nd core broken out and filled with concrete and reinforced through the cell
- Solid in-situ slabs: Concrete cast level with (or above) the top flange
