The patented manufacturing process used to produce Thor Heliforce Bars doubles the effective tensile strength of the stainless steel round wiew by means of double work hardening.
The perfect pitch technology unique to Thor Helical products forms a precise helical path in the material into which they are driven, providing an accurate mating interlock. Each Thor Helical section is balanced in section, stiffness and pitch to optimise ease of driving, improve reliability and enhance performance.
The unique manufacturing process increases the tensile strngth of the base material considerably. During the final stages of manufacture it is subject to loads which, if there was a defect in the base material, will cause it to distort or fracture. If this happens it will be readily apparent and immediately rejected. Consequently, the strength and integrity of Thor Heliforce Bars can be 100% assured.
Thor Heliforce Bars
The helical form gives some of the elastic characteristics of a coil spring. A helical bar on its own will stretch rather more than round wire of the same cross sectional area under a given load since the modules of elasticity or 'E' value is lower. These characteristics are very useful when connecting structural elements liable to move slightly, or independantly of each other, in relation to cyclic and differential movement.
When the Thor Heliforce Bars are embedded in bed joints of strong grout this tendancy to stretch under load is effectively restrained by interlocking with the grout. This has the effect of the helical bar and grout working together as a system to provide a satisfactory repair solution. Round wire, which cannot interlock with any surrounding grout and is dependant on frictional bond alone, will tend to act independantly of the grout and consequently result in lower structural capacity than the Thoe Helical Bar and Grout System.
The embedment of the Thor Heliforce Bar into chases cut into masonry and filled with strong grout, enables the Thor heliforce Bar and Grout to act in tension or compression as necessary depending on the load carrying conditions.
Encasement in strong grout also enables helical bars to contribute fully to the resistance of vertical shearing forces. The grout provides strong reacting surfaces to restrain such bending and transfers stresses straight through to the adjacent masonry surfaces.
The pronounced helical fins provide clearance spaces around the central core material of the helical bars so that these become fully surrounded with grout without undue difficulties.
Thor Helical Bars are available in 5mm, 6mm, 7mm and 9mm diameters. the material is Austenetic Stainless Steel in either mill grade 304 as standard or grade 316 to provide additional long term corrosion resistance.
The 6mm Heliforce Bar is the dominant material used in the Thor Heliforce Beaming System, although 5mm should be considered for very thin bed joints. Where the pinning of structures is required either 7mm or 9mm diameter Heliforce Bars are used. Thor Helical Remedial Heliforce Bars are used extensively for crack stitching, masonry beaming, lintel reinforcement and as part of Lateral Restraint schemes for bowed walls.