Is there an option to install the Hilti HIT‑Punching Shear Strengthening Solution within a recess in the slab so that the bolts are concealed? If so, where can I find the technical data for this configuration, including the minimum recess dimensions required?
Yes. A concealed or recessed installation is available for the Hilti HIT-Punching Shear Strengthening System. This configuration is permitted only from the tension side of the slab. After installation, the recess must be filled with a suitable high-strength mortar or grout, and the recess depth must remain smaller than the clear concrete cover.
The required recess dimensions depend on the selected threaded-rod size and HIT-SW washer assembly. The HIT-SW outside diameter ranges from 44 mm for M12 to 70 mm for M24. Therefore, the recess should be detailed as part of the project-specific design rather than using one standard dimension for all rod sizes.
The configuration and technical requirements can be found in Annexes 2, 3, 5 and 8 of the applicable Hilti HIT-Punching Shear Strengthening approval, together with the HIT-Shear and HIT-Punching Shear installation instructions
