Masonry Magazine January 1974 Page. 57
Large Masonry Project
Utilizes Mountain Climbers' Technique
An idea borrowed from mountain climbing pros was successfully used to tie a new, one-course brick veneer to the existing concrete wall of Chancellor Elementary School in Irvington, N. J. Keeping in mind iron pitons which mountain climbers drive into rock crevices, Herman N. Wenson, consulting engineer, developed a tie-back system which would resist horizontal as well as vertical pulls.
Because there wasn't a crack or crevice in the sound, 60-year-old concrete wall, points of attachment had to be created. Holes (4" deep by ½" dia.) were drilled into the concrete wall at a 30-45-degree angle downward from the horizontal, and filled with a non-shrinking epoxy compound called Colma-Dur Gel manufactured by Sika Chemical Corp., Lyndhurst, N.J. A double-twisted, 14-gauge stainless steel wire was inserted into the epoxy gel. Later, this would be tied into the steel reinforcement within the brick wall.
The question was: could the multiple ties withstand a 14-to-million lb. suction that might possibly be exerted by wind gusts? Before mountain climbers trust their weight to a new hold, they test it by throwing their weight on it. To test his epoxy "pitons," Wenson conducted field experiments using holes plugged with Colma-Dur Gel to determine their strength under load.
(A) Holes were drilled downward in concrete wall at a 30° angle spaced 2' x 4' on all four faces of building. (B) Using a rubber squeeze ball, workman blew dust out of holes just before grouting. (C) Colma-Dur Gel, packed into caulking gun, filled the " dia. holes in 30 seconds. (D) Workman inserted 12"-long double strand of stainless steel wire into grouted hole, with a 36" x 6" eyelet on one end of the wire inserted in the grout and two ends projecting out of the wall. When the brick course came up to the elevation of the protruding tie wires, the mason tied them to the steel reinforcement in the brick wall. (E) Mortar covered the reinforcement to which the double strands of stainless steel wire have been tied. Bricklaying proceeded for 10 courses up to the next level of tie wires.