Description
Due to the new tenant Aldi’s demand for higher loads in the sales area, the flat ceiling built in 1977 had to be structurally reinforced. Four additional supports in the basement, fitted with external steel head and additional CFRP adhesive reinforcements on the bottom side of the ceiling, now achieve the desired result.

In order to increase the insufficient punching shear resistance, re-bar 16 were installed as prestressed bending reinforcement on the upper side of the slab for the four new columns. The prestressing of the re-bars means that the additional tensile reinforcement is at a higher stress level from the start.

For the installation, the concrete surface was hydromechanically roughened beforehand in the area of the negative bending tension zone and the bars were then positioned. The end areas for the anchoring over a length of approx. 60 cm were then filled with SikaGrout^® 314. Once the anchoring zones had cured sufficiently, the rods were heated to a temperature of 300°C using a gas burner in order to create the shape memory effect and thus the prestressing. Finally, the free length between the anchoring zones was also filled with cementitious grout to create a fully bonded system to the surrounding concrete.

The following aspects are particularly noteworthy:

•  High ductility of the additional reinforcement
• Active tensile reinforcement right from the start
• Easy-to-apply reinforcement with pre-tensioning without complex stressing equipment (hydraulic jack) and anchor heads
• Recyclable material after dismantling, re-bar can be 100% reintroduced into the stainless steel production cycle
• High situational adaptability of the reinforcement system
  

Product
memory^®-steel re-bar 16 with SikaGrout^® 314