Structural strengthening by additional prestressing

Main use cases

01. Increased loads

- Increased dead loads
- Increased service, wind or snow loads

02. Ageing of prestressed structures

- Corrosion of internal prestressing steel
- Stress relaxation of prestressing steels

03. Connecting structures

- Change from isostatic to multi-span beam
- Connect adjacent buildings for higher seismic resilience

Additional prestressing reinforcements

Due to the ever increasing traffic loads on bridges, and the inevitable ageing of prestressed structures of all kinds, it is often necessary to use additional prestressing to recover or increase their initial load-bearing capacity.
This technique consists of adding external forces to modify the stress condition of an existing structure (reinforced or prestressed concrete, masonry or timber structures), so as to bring it back to its initial working condition, or even to increase its load-bearing capacity.

 

The active reinforcements are loaded at the time of application, which has the advantage of strengthening the structure independently of its subsequent loading, while precisely controlling the level of forces introduced.

Additional prestressing is used to relieve bent elements of insufficient strength or stiffness by compensating for the effects of part of their permanent loads.

The additional prestressing reinforcement is essential to the operation of the reinforced structure and as such its durability is critical. Freyssinet advises you on the choice of corrosion protection for prestressing steel.

One-stop specialist services

From structural analysis to execution

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A wide range of applications

Strengthening of building frames

Additional prestressing is achieved by means of a few protected and individually anchored monostrand tendons, which are straight or deviated. The connection of the anchors to the existing structure requires only small blisters and can, in some cases, be dispensed with.
  • Low service disruption
  • Fast installation process
  • Low aesthetic impact

Strengthening of bridges

The strengthening of bridges requires additional prestressing reinforcement of very high capacity and compactness, whose service life is compatible with that of the structure to be reinforced.
  • Very high reinforcement capacity
  • Compact solution
  • High durability

Strengthening of storage units

Additional prestressing in the form of hoops is an ideal reinforcement to increase the capacity of storage structures with a circular cross-section, when subjected to high internal pressure.
(i) Anchoring 1X15 for radii from 6m to 27.5m (ii) Anchoring 2X15 for radii from 3.7m to 5.5m
    • Low service disruption
    • High durability
    • Hoops spacing adjusted
      to the need

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