re-bar method for concrete structures

«for statically and dynamically loaded elements»

Post-strengthening of structures

The Ø10 or Ø16 mm ribbed re-bar is end anchored in Sika repair mortar. After sufficient cure of the end anchorage, the re-bar is activated by a gas burner. Finally, the remaining free length is also embedded in mortar. The installed re-bar acts as an internal prestressing. re-bar 10 U-profiles (stirrups) are embedded in Sika repair mortar and activated using an electric current.

In concrete for new construction (internal downstand beam)

In new concrete structures, re-bar 16 is used analog to traditional reinforcement. Activation is performed by resistive heating with electric current applied before the concrete formwork is removed.

Application

Flexural strengthening for positive/negative bending moments

  • changes in loads/operation
  • changes in the load-bearing statical system (Removal of columns/supports, new openings in slabs)

Improvement of serviceability limit state

  • by reduction of deflections
  • reduction of crack width
  • by decreasing the stress level of internal reinforcement (fatigue loads)

Shear strengthening

  • Increase of shear capacity
  • Strengthening of highly damaged structures
  • Improvement of serviceability limit state (see above)

Seismic strengthening

  • Owing to weldability of memory®-steel, simple anchorage methods are possible

Strengthening in new construction

  • High slenderness Slabs/beams
  • Internal prestressed beams

Often appropriate

Combined flexural/shear applications on bridge structures

re-bar is suitable for partial and complete rehabilitation of a bridge beam or solid deck downstand. For conversions or repairs to old, carbonated concrete sections, memory®-steel re-bar is installed in new mortar layers for flexural or shear strengthening. The cementitious mortar layer functions as a protective alkaline environment for the embedded steel reinforcement. These strengthening works create a durable load-bearing system with integral corrosion protection for memory®-steel and the existing internal reinforcement.

Flexible anchorage options:

For flexural strengthening, re-bar is anchored behind or on the zero-moment line, and for shear strengthening, re-bar is anchored in the compression zone. Transmission of the prestressing force is normally achieved through the bonded mortar (1), alternatively end hooks can also be used, in which case the anchorage generates a better resistance due to the deeper penetration into the core concrete (2). Additional special solutions such as bonded or externally bolted steel angles with welded re-bars are also possible options (3).

Prestressed re-bar shear stirrups are particularly suitable for applying pressure over the shear bond between the new mortar and the bearing concrete substrate (4).

Tested Sika products
  • Sika® FastFix-121 Cement mortar for sealing surface cracks
  • SikaGrout®-314 N Shrinkage-free, Class R4 precision grouting mortar for filling formwork holes or cut grooves
  • Sika® InjectoCem-190 Very fine cement-based crack injection mortar
  • Sika MonoTop®-412 N/DE, Eco, -4012 Shrinkage-compensated, Class R4 wet sprayed mortar
  • Sika MonoTop®-422 PCC Shrinkage-compensated, Class R4 repair mortar
  • Sika MonoTop®-452 N Shrinkage-compensated, Class R4 repair mortar for horizontal surfaces
  • Sika MonoTop®-910 N/ECO, -1010 Reinforcement corrosion protection and bond coat
  • Sika® Rock Gunit BE-8 Dry sprayed mortar (cementitious, alkali free)
  • Sika® AnchorFix®-3030 Epoxy adhesive supplied in «cartridge» for anchorage fixings»

re-fer memory®-steel has been tested in systems with Sika sprayed concrete repair and grouting mortars, plus Sika fire and corrosion protection products. re-fer gives no guarantee if other mortars and products are used in combination with memory®-steel.

Application video

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