03-01-2014, 04:03 AM
1/2" rebar has 1.57 square inches per inch of length surface area. By 6" = 9.42" square surface bond at 125psi is 1178 lbs. resistance force to extraction. Here's the rub, a vertical shock force of a structure resisting downward motion of the earth with a mere 1178lbs resistance force applied to a .625" diameter hole in lava, will result in one of two things, snapping lava rock upward or instant extraction of the anchor from the rock. Failure.