KÖCO's head bolts have been used for decades for anchoring steel components in solid constructions. They transmit forces and moments in any direction from the steel part into the concrete. The positive fit of the bolt head ensures transmission even in the tensile zone of the concrete. Lightning-fast welding of the head studs with the proven KÖCO stud welding systems is an important factor for the safety and economy of the connection.
Steel components with KÖCO head bolts welded on are regulated by the building authorities with regard to the design procedure, manufacture and installation in European Technical Approvals (ETA-03/0039 for structural steel and for stainless steel). The design method is based on investigations carried out at the beginning of the 1990s, mainly in unreinforced concrete. The use of specifically inserted rebound reinforcement to increase the load capacity on tension and shear is then possible, but not the consideration of existing reinforcement. This and some other restrictions often lead to uneconomical anchoring, sometimes a solution cannot be found in purely arithmetical terms, taking the approval into account.
For several years, CEN/TC250/SC2/WG2 has been developing a comprehensive new recommendation for design methods for anchorages in concrete, based on new scientific findings. Publication is expected in 2008, after which the assessment procedure of the approval will be changed to the new CEN rules. The use of head bolts in components with existing reinforcement will then become considerably easier.
After many years of the successful use of the KBZUL design program, we are now presenting the improved StudCalc design program based on the latest scientific findings.
StudCalc offers a fully graphical interface on which the steel component and the concrete slab can be freely scaled, rotated and moved. The geometric data (dimensions of concrete slab and fixture, edge distances and centre distances) can be entered directly here. Changes are visible graphically.