For several decades, KÖCO shear connectors have been used to anchor steel components in solid concrete constructions. They transfer forces and moments from the steel to the concrete in every direction. The positive-type joining of the bolt head ensures safe transfer even in zones of the concrete subject to tensile stress. Extremely fast welding on of the shear connectors with the proven KÖCO stud welding equipment is an important factor in providing a safe, cost-efficient connection (example: base of a support leg).
Steel components with KÖCO shear connectors welded on are subject to European Technical Approval regulations for building construction (ETA-03/0039 for structural steel and for stainless steel) in respect of calculating their dimensions, their production and assembly. The current design methods are based on findings from research carried out at the beginning of the 1990s, mainly on non-reinforced concrete. According to these findings, the use of connection reinforcing bars to increase the load capacity for tensile stress and transverse forces is possible, but without taking into account any reinforcement already in place. This and some other restrictions frequently lead to uneconomical anchoring, and in some cases design solutions calculated in compliance with the relevant approval procedures have proved impractical for cost reasons.
CEN/TC250/SC2/WG2 has now been working for a number of years on a detailed set of new recommendations for the design of anchoring devices, based on new scientific findings. Publication is expected in 2008; thereafter the approval procedure will be subject to the new regulations according to CEN. The use of shear connectors in components with existing reinforcement will then become considerably less complicated.
After many years of successful application of the KBZUL design program, we have now introduced the improved, extended StudCalc design program based on the latest scientific findings. StudCalc is equipped with a completely graphical desktop, on which the steel component and the concrete slab can be freely scaled up or down, turned and moved about. The geometrical data (dimensions of the concrete slab and the component to be attached, edge and centre distances) can be directly entered here, with immediate graphical visualisation of the resulting changes.