Thor Helical bars provide effective masonry repairs to reinforce poorly supported, damaged or cracked walls. The stainless steel helical reinforcement bars are introduced into walls to form deep masonry beams, which span across the area of masonry failure, to redistribute loads and greatly enhance the tensile, shear and flexural capacity of the wall.

Retro-reinforced masonry beams are formed in existing walls by reinforcing two separate mortar beds, each with a pair of stainless steel Thor Helical reinforcing bars embedded in WHO60® structural repair grout.  The reinforced brickwork, blockwork or stone beams are typically used for lintel repairs, or to aid subsidence repairs, by spanning between piles or slabs to carry vertical loads.

The reinforced bed joints form chords that represent the upper and lower flanges of a beam. One chord combines with the two surrounding courses to carry compression and the other reinforcement chord acts in tension. The un-reinforced masonry between the chords represents the web of the beam and carries horizontal shear.

Factored load tables from the B.R.E. Design Guide to the Thor Helical System of Masonry Reinforcement are used to establish load capacity, given the spacing between top and bottom reinforcing bars, and the span between known supports and confirmation that bond strength of the bed joints between the chords is sufficient to take the required horizontal loads.

A series of grouted helical wires can be wrapped around a building to increase its flexural capacity, as part of a seismic up-grade, and by creating a ring beam with resilience to horizontal loads, much like hoops irons strapped around the slats of a barrel.

 BRE Report - Thor Helical Reinforcement