Re-Fer

Description
Next to the freight depot in Lucerne, a precast hollow core slab needed to be retrofitted. The consulting engineer required a strengthening solution, which allowed for a simple and fast prestressing of the place. The force introduction ideally occurred at the intersection of two webs. In this area, a sufficiently high concrete section was available. re-bar was placed in a previously cut groove and subsequently anchored at both ends. Activation took place after curing of the cementitious anchors. A too high prestress force could damage the existing structure. Earlier tests delivered the correct prestress force and the related activation temperature.

A controlled heating allowed to properly apply the necessary temperature and hence introduce the correct prestressing force into the concrete substrate.