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.
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)
Load with 400mm tie-length bonded to brickwork with WHO-60 grout
TYPICAL MECHANICAL PROPERTIES OF THOR HELICAL GROUT TIES
|8mm Tie Bar
|9mm Tie Bar
|0.2% Proof Stress
|Ultimate Tensile Strength*
|Mean Tensile Capacity #
* 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
|Compressive Strength – 7 days
|Compressive – 28 days
|Tensile Strength – 28 days
|Flexural Strength – 28 days
|Young’s modulus (fully cured)
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