Long Helical Bars    Product

Long Helical Bars

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Thor Helical long helical bars are used to form array of load bearing brick beams which strengthens and stabilizes structures of damaged masonry.

The high tensile, stainless steel brick reinforcement bars are concealed within slots cut into mortar beds at predetermined levels using thixotropic, cementitious grout. This achieves an extremely strong bond deep into masonry beams that span areas of poor support.

The retrofitted masonry beams are particularly effective at carrying and redistributing vertical loads over areas of localized foundation movement and over failed lintels. These long helical bars are available in lengths of up to 10m and in diameters of 5, 6, 7, 8 and 9mm.

Benefits:
  • Conform to BS EN 845-1: 2013 and conditions for CE Marking for strapping masonry together
  • High tensile strength of 1050-1200M/mm2 – Twice that of rebar (See BRE GBG62)
  • Absorbs stress and redistribute vertical loads
  • Deliver high tensile reinforcement with unique torsional elastic yield characteristics
  • Cost effective, quick, reliable and less disruption to install
  • Increases tensile, shear and flexural strength of masonry.

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Description

International Manufacturer of Precision Engineered Helical Bars, Wall Ties & Fixings

Thor Helical long helical bars are used to form array of load bearing brick beams which strengthens and stabilizes structures of damaged masonry.

The high tensile, stainless steel brick reinforcement bars are concealed within slots cut into mortar beds at predetermined levels using thixotropic, cementitious grout. This achieves an extremely strong bond deep into masonry beams that span areas of poor support.

The retrofitted masonry beams are particularly effective at carrying and redistributing vertical loads over areas of localized foundation movement and over failed lintels. These long helical bars are available in lengths of up to 10m and in diameters of 5, 6, 7, 8 and 9mm.

Benefits:
  • Conform to BS EN 845-1: 2013 and conditions for CE Marking for strapping masonry together
  • High tensile strength of 1050-1200M/mm2 – Twice that of rebar (See BRE GBG62)
  • Absorbs stress and redistribute vertical loads
  • Deliver high tensile reinforcement with unique torsional elastic yield characteristics
  • Cost effective, quick, reliable and less disruption to install
  • Increases tensile, shear and flexural strength of masonry.

PRODUCT SPECIFICATION

Thor Helical bars are available in AISI304 grade Austenitic Stainless Steel. AISI316 stainless bars are available on special request. The helical bars are supplied in the following standard sizes

  • Lengths: 7.0m, 8.0m, and 10.0m
  • Diameter: 5mm, 6mm, 7mm, 8mm and 9mm

TYPICAL PERFORMANCE LOADS for retrofit brick beams (taken from BRE Testing, including conservative factors of safety)

Span Depth of Beam
300mm 450mm 600mm
1.2m
21.8kN 21.8kN 21.8kN
1.6m
16.4kN 16.4kN 16.4kN
2.0m
13.1kN 13.1kN 13.1kN
2.4m
10.9kN 10.9kN 10.9kN
2.8m
9.4kN 9.4kN 9.4kN
3.2m
-N/A- 8.2kN 8.2kN
3.6m
-N/A- 7.3kN 7.3kN

Brick beams formed by installing two chords of  double 6mm bar bedded in WHO-60 Grout. Bars extended 500mm either side of the opening (span). The depth of the beam is the distance between each chord of double helical bars. Loads are expressed in kN per linear metre.

TYPICAL PERFORMANCE LOADS for concealed strapping (taken from CE Mark Testing)

BS EN 845-1:2013 National Annex NA states that the bars need to provide an equivalent performance to the prescriptive 30mm x 5mm lateral restraint straps and the tension straps should have a declared tensile load capacity of at least 8kN

Bar Diameter Bars per Joint Tension Load
6mm Single Bar 8.39kN
7mm Single Bar 9.75kN
8mm Single Bar 11.06kN
9mm Single Bar 11.50kN
6mm Double Bar 16.00kN
7mm Double Bar 17.65kN
8mm Double Bar 17.65kN
5mm Triple Bar 14.34kN

Single bars bedded 20mm deep: Double bars placed 15 & 25mm deep: Triple bars buried 10, 20 & 30mm deep. Height of slot cut at least 3mm greater than diameter of the helical bars. Depth of slot cut to 35-40mm. Bars bedded at least 400mm beyond crack. Bars bonded with WHO-60 Grout

TYPICAL MECHANICAL PROPERTIES OF THOR HELICAL PROFILED BARS
Diameter CSA (mm2) 0.2% Proof Stress (N/mm2) Ult Tensile Strength (N/mm2)* Mean Tensile Capacity #
5mm 6 >880 1025 – 1225 7 kN
6mm 8 >870 1025 – 1225 9 kN
7mm 10 >880 1025 – 1225 11 kN
8mm 13 >790 1025 – 1225 14 kN
9mm 16 >850 1025 – 1225 17 kN

* Ultimate Tensile Strength is measured within a calibrated tolerance of +/- 2% # Mean Tensile Capacity is an indicative value derived from CSA x Mean UTS

This video demonstrates the helical bars being used to create deep brick beams to span a window opening. The stainless steel helical reinforcing bars are bonded with WHO-60 polymer modified grout into cut slots cut into masonry. It offers a quick, simple and durable solution for strengthening and stabalising damaged masonry structures

CE Mark Declaration of Performance Helical Bars (PDF)