Due to an insufficient flexural and punching reinforcement, a reinforced concrete slab had to be strengthened. Firstly, the upper surface was roughened. Several re-bars were afterwards put in place and anchored at both ends in a layer of a cementitious mortar. After a sufficient curing, the bars were activated and hence prestressed by heating with a gas flame. After prestressing, the remaining free length between the anchorage areas was also covered with mortar. The method allows for a simple and efficient prestressing and strengthening without the need for complicated machinery on site.
Implenia, SikaBau, re-fer AG
Flexural and punching strengthening
Bärtschi Partner AG