Grout Ties

Grout ties are fixed into masonry walls with a high strength polymer modified grout.  The deep trough of the helix provides an excellent key between the stainless steel reinforcing rod and the cement based grout.

Description

Grout Ties are helical bars that are bonded into masonry.  The strength of separating masonry layers can be restored by using the ties, fully grouted into deeply drilled bore holes. Grout ties are used to reinforce thick or rubble filled walls, reconnect external walls with internal partitions, stabilise parapets and pin masonry arch layers in buildings, bridges and tunnels.

To install the ties 14-18mm diameter clearance holes are drilled into the masonry to a depth that is at least 25mm longer than the tie. Holes are thoroughly washed out with clean water. WHO-60 polymer modified grout is pumped to each hole, filling the bore and any voids.  Stainless steel helical tie bars are wound into the unset grout, displacing it tightly into voids. Once set, the high strength grout interlocks with the peaks and troughs of the helix to bond the grout ties to the masonry.

Thor Helical do not recommend installation procedures that involve inserting the tie into the pinning nozzle and grout expelling the tie/grout composite in a single operation.  This technique is flawed and may lead to inadequate bonding to the masonry.

Products required for the installation of grout-bonded ties are:

  • WHO 60 polymer modified grout (yield=3l); 1 tub for 10 ties
  • Mortar gun, pipe, cone and brick pinning nozzle set
  • Mixer paddle

Grout ties are supplied loose, ready for resale packaging, on pallets containing 480 ties.

 

PRODUCT SPECIFICATION

Thor Helical grout ties are available in AISI304 grade Austenitic Stainless Steel.  The ties are supplied in the following standard sizes

  • Lengths: 0.5m, 0.75m and 1.0m
  • Diameter: 8mm and 9mm

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

TYPICAL PERFORMANCE LOADS (taken from CE Mark Testing)

Tie Size
Tension Load
8mm Diameter 11.06kN
9mm Diameter 11.50kN

Load with 400mm tie-length bonded to brickwork with WHO-60 grout

 

TYPICAL MECHANICAL PROPERTIES OF THOR HELICAL GROUT TIES

Product Attributes
8mm Tie Bar
9mm Tie Bar
CSA 13mm2 16mm2
0.2% Proof Stress >790N/mm2 >850N/mm2
Ultimate Tensile Strength* 1025-1225N/mm2 1025-1225N/mm2
Mean Tensile Capacity # 14kN 17kN

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

 

TYPICAL PROPERTIES – WHO-60 Grout

Physical Properties Strength
Compressive Strength – 7 days 35N/mm²
Compressive – 28 days 55N/mm²
Tensile Strength – 28 days 5N/mm²
Flexural Strength – 28 days 12N/mm²
Young’s modulus (fully cured) 13kN/mm²

This video guide demonstrates the method of how to pin masonry arch layers using a series of Grout Ties, bonded into walls with WHO-60 grout. The ties offer an effective and reliable solution for stabilising separating wall layers