Opening in a reinforced-concrete load-bearing wall in Mandelieu-la-Napoule (06)

Structural study and sizing of the steel structure by a specialist engineering office

The engineering office OMPT Structure was called in to create a 3.15 m opening in a 16 cm thick reinforced-concrete load-bearing wall, in an apartment in Mandelieu-la-Napoule.

This interior renovation project (open kitchen) required a complete structural study, a reinforced-concrete calculation report and precise sizing of the steel reinforcement, in accordance with Eurocodes.

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Structural context of the building

The apartment is on the first floor (R+1) of a four-storey (R+4) apartment building above the ground floor.

Points analysed:

• Reinforced-concrete load-bearing wall – 16 cm thick
• Wall stacked above on the second floor (R+2) in the same alignment
• Setback façade on the third floor (R+3) (terrace)
• Verification of dead and imposed loads
• Overall stability study

This analysis made it possible to determine the transmitted forces and to size the steel sections suited to a wide opening (3.15 m).

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Reinforcement principle – UPE steel frame

The chosen solution relies on:

• Two UPE steel sections
• Sandwich installation on either side of the concrete wall
• Bolting with high-strength through rods

This system provides:

✔️ Transfer of vertical loads
✔️ Redistribution of forces to the bearings
✔️ Lateral stability of the wall
✔️ Securing before cutting

The reinforcement is installed before any opening is made, avoiding heavy propping.

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Assembly and fixing

The steel portal frame comprises:

• Two vertical uprights
• A horizontal lintel sized by calculation
• Load-spreading base plates
• Continuous welds

Fixing to the reinforced-concrete wall:

• HR 6.8 bolts – M16
• 40 cm spacing
• Controlled tightening
• Gradual loading of the floor

This method guarantees a safe transfer of loads before sawing.

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Controlled cutting of the load-bearing wall

Once the reinforcement is approved:

• Diamond-blade sawing
• Precise cut
• Vibration limited
• Prevention of micro-cracking

A final check is carried out: verification of the bearings, bolt tightening and structural sign-off.

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Structural engineering office in the 06 and 83 departments

OMPT Structure works throughout:

06 – Alpes-Maritimes: Nice, Cannes, Antibes, Grasse, Menton, Mandelieu-la-Napoule

83 – Var: Fréjus, Saint-Raphaël, Draguignan, Sainte-Maxime, Toulon

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Planning to open up a load-bearing wall?

Apartment, villa or apartment block: creating an opening in a reinforced-concrete load-bearing wall requires a qualified structural engineer.

Trust OMPT Structure for a reliable, optimised study that complies with current standards in the 06 and 83.