Pinning concrete forms to asphalt
Last month, I had a job fixing a deteriorating sidewalk. The new sidewalk was to have a 6-in. tall curb beginning at the edge of some asphalt pavement. I needed to install a 2×6 formboard on a slight angle, and I wanted to leave the forms in place for several days after the pour so that the concrete wouldn’t have to do battle with car tires until it had a chance to cure. Regular steel form stakes would stand above the forms and be a hazard. And there was no way to drive wooden stakes into the pavement.
As shown in the drawing, I used 8-in. lengths of 1/2-in. rebar to solve the problem. First, I drilled 1/2-in.-dia. holes in the pavement, 2-1/2 in. deep and on 4-ft. centers.
Next I cut a bunch of Simpson TP37 tie plates in half. I used my modified 3-1/2-in. by 3-in. plates to attach the formboards to the rebar pins. As I ran the four screws that hold each plate to the board, the tie plates bent around the rebar. I then ground off the top edges of the rebar so that they wouldn’t present a problem to a rubber tire.
A week later, when it was time to strip the forms, I noticed a lot of black tire marks along the formboards. Made me glad the concrete had been protected. After unscrewing the tie plates, I used my Vise-Grip pliers to twist and pull the rebar stakes right out of their holes.
John La Torre Jr., Tuolumne, CA