Slab Strengthening
Restoring the load capacity of slabs whose service loads have changed, whose spans are challenged or which have suffered damage.
The member life happens on is the member that changes most.
When a building’s use changes, the slab is the first member to feel it. A warehouse turned into an office, an office turned into an archive, a production floor where a new machine is installed; each places loads on the slab that its design never foresaw. Slab inadequacy usually shows itself as deflection, vibration or cracking; but capacity can also be exceeded with no visible symptom at all.
In slab strengthening, the method varies with the type of problem: flexural capacity can be increased with carbon fiber systems, the span can be divided with new beams, the section can be enlarged from above or below. The right method is defined by the condition survey and the strengthening design; we plan the application with the life on the floor above and the operation on the floor below in mind.
- Use-sensitive planning: The intervention is phased around the use of the floors above and below.
- A range of methods: From carbon fiber to section enlargement, the right method is selected per the design.
- Focus on vibration and deflection: Not only strength but comfort in use is considered.
- Opening compensation: The perimeters of openings cut later are strengthened by design.
Wherever the slab is under strain.
Slab strengthening arises for different reasons; the reason defines the form of the intervention.
Increased service loads
New loads from archives, storage and equipment.
New machinery and equipment
Carrying concentrated heavy loads.
Cutting openings
Compensating for stair, elevator and service openings.
Deflection and vibration
Correcting behavior that disturbs comfort in use.
Damage and corrosion
Capacity loss from reinforcement corrosion and cracking.
Mezzanine additions
Tying new mezzanines into the existing system.
The four conditions for touching the structure.
Every intervention on the structural system follows the same discipline: diagnosis, design, supervised application and complete records.
Diagnosis and design
The existing condition is documented; the intervention is limited to the scope and detail defined by the strengthening design.
Surface and member preparation
The application surface is brought to the condition the design requires; the preparation defines the system’s life.
Supervised application
The application is carried out under civil engineering supervision, adhering to the manufacturer’s system approvals.
Records and handover
Every stage is documented; the work is handed over with a traceable application file.
The reinforcement goes where the slab is in tension.
In carbon fiber reinforcement, the strips are applied to the slab’s tension face, at the spacing and in the direction the design defines.
- Existing reinforced concrete slabThe strengthened member, its condition established beforehand.
- Epoxy adhesiveThe bond providing force transfer between strip and slab.
- Carbon fiber stripsTaking up the tensile force, applied to the underside: the reinforcement.
- Protective layerThe layer protecting the reinforcement, ready for a ceiling finish.
The right method for the situation.
Method selection belongs to the strengthening design; the headings below represent the most frequently applied approaches.
Carbon fiber reinforcement
Capacity increase from the underside, preserving the section.
Topping-based section enlargement
Strengthening with a new bonded concrete layer.
New beam additions
Dividing the span with steel or reinforced concrete beams.
Opening perimeter reinforcement
Strengthening the edges of cut openings.
What is expected of a slab strengthening.
Capacity increase
The slab carries the new use’s loads safely.
Vibration control
Comfort in use improves along with the behavior.
Phased application
Planned around the use of the floors above and below.
Section preservation
With the right method, floor height is preserved.
Fidelity to the design
Spacing, direction and scope never deviate from the design.
Traceable records
The application file is handed over complete.
The scope is defined by the design, not by assumption.
The classification below is indicative only. The final scope is defined by the condition survey and the strengthening design.
The slab, or another member?
The source of the problem may lie outside the slab; let’s find the right address together.
Technical documents for members
Technical data sheets, safety data sheets and application specifications are available in the membership area open to corporate clients, architects and engineers. Access is free with membership.
Other strengthening systems
Let’s give your slabs the strength of their new use.
Share your change of use or the behavior you have observed with us; let’s define the scope together, within the framework of the design.