Reinforcement of the supporting structure

Rahman Baravi, Site Manager

Reinforcement of the supporting structure by increasing punching shear resistance in Adliswil. As happens in many older covered parking facilities, the punching shear resistance of the pillar supports in the Rütistrasse car park in Adliswil no longer met today's standards, so reinforcement was required. The Zurich Building Reconstruction team installed durable punching shear armouring at Rütistrasse 60 in Adliswil, thereby increasing the structural safety of the parking facility.

Punching shear reinforcements are 'surgical' interventions in existing concrete structures. The aim is to install additional reinforcements at statically sensitive points without damaging the supporting structure that is already in place. Just as in an operating theatre, preparation is the most critical phase – in fact, it accounts for half the work. The armouring components in the reinforced concrete ceiling had to be precisely located and marked in the area around the supports. This avoided drilling of the existing reinforcements. In many cases, structural plans were no longer available – so the distances between the reinforcements had to be evaluated beforehand. The distance between the base reinforcing rods determines whether the anchor heads can be recessed or if they have to be surface-mounted. 

In the Rütistrasse property, Weiss+Appetito's specialists ascertained a distance of 20 cm between reinforcements, so the anchor heads could be recessed. The reinforcement rods in the two lower layers were drawn in on the plan, and a new proposal for the anchor locations was submitted to the engineer to avoid any drilling errors. The engineer checked the calculations in our proposal and gave the green light, so Weiss+Appetito started work.

In these cases, dry drilling is used with a hollow drill and dust extraction. This ensures that the drilled hole is rough enough to ensure a good bond. The resultant dust is extracted directly, so the process is practically dust-free, and there is no adverse impact on surrounding areas.

After this successful operation, it is now almost impossible to see any signs of the intervention in the Rütistrasse parking facility. However, the load-bearing capability of the concrete structure has been increased – helping to preserve the property's value. The result: the client and also the Weiss+Appetito professionals involved are highly satisfied with the results of the work.

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