Hi, I have a design-build contractor asking if they can anchor sprinkler line hangers into the underside of an existing PT concrete slab. They are specifying 1/2" diameter KB-TZ anchors. We have recommended that they scan to locate the existing prestressing strands, but we wanted to know if there is a recommended minimum distance for the anchors to be located away from the prestressing?
Hi Jordan,
While there is no exact value, engineers try to embed away from the post tension cables so it is important to know the distance from the surface to the strands. A conservative approach could be to ensure that there is enough concrete thickness between the surface of the concrete and the strands to achieve the minimum concrete thickness. This information can be found in ESR-1917.
Regards,
Ashley