Innovation: Magnetic attachment of rails and strips of the VS-ISI-System 3D to steel formwork

Magnetic fasteners for concrete components are increasingly in demand due to their efficiency. The objective was therefore to develop a simple and cost-effective solution for attaching rails and strips of the Pfeifer VS-ISI System 3D to steel formwork using magnets.

The Pfeifer VS-ISI System 3D is used for force-fit connections of prefabricated walls and/or columns. The rails and strips are positioned at the front over the full height of the component and cast into the concrete. After formwork removal, the protective adhesive tape is removed and the rope loops are folded out. On site, the prefabricated elements are placed next to each other so that the rope loops overlap, and a reinforcing bar is inserted from above through the overlapping loops along the entire component height. The joint is then filled, completing the connection.

When manufacturing the precast elements, the rails/strips must be correctly attached to the formwork so that they remain in position during concreting. This is important to ensure that the rope loop connection functions properly and that loads can be transferred reliably.

Until now, different methods have been used to fix rails and strips to formwork. The most common method is to apply hot glue directly to the adhesive tape on the front of the rail or strip to stick the profiles to the formwork before concreting. However, when the formwork is removed, the hot glue residues have to be laboriously removed from the formwork.

Others use more complex magnetic systems, which require the protective cover of the profiles to be removed and then replaced before they can be attached to the formwork.

The innovation of the Pfeifer solution is that the magnetic fastener can be simply inserted into the rails and strips – without any additional effort.

To do this, the tip of the magnetic fastener is inserted through the existing pin holes in the adhesive tape on the rails/strips and inserted into the blue sealing clip underneath – without having to remove the adhesive tape. The rails/strips can then be positioned on the steel formwork.

After stripping the formwork, the magnets remain attached to the formwork and only need to be collected.

This significantly simplifies the installation process compared to the fastening methods previously available. Customers who are already using the new magnetic fastening system report time savings of 5-6 minutes per rail/strip when fastening to steel formwork – compared to the methods previously used. Especially for precast plants that use many long joints as rope loop connections, this can add up to enormous overall savings by the end of the year.

In addition, the use of magnetic fasteners also makes ecological sense, as they can often be reused.