Hi I am working on a project involving pipe supports on new R.C pads. The anchors in the attached designed are to be cast in a new recently poured pad. Our client needs to drill and fix them as soon after casting as possible. What is the minimum time after pouring is drilling and setting permissible please?
Under EN 1992-4 (SANS 51992-4), post-installed anchors are designed on the basis that the concrete is at least 21 days old at installation. The ETA resistances also assume the concrete has reached the specified strength class. The recommended minimum is therefore 21 days after pouring before drilling and setting.
Installing earlier is outside the scope of the ETA and the design. If the programme cannot wait, it is only an option if the engineer of record accepts it on the basis of tested concrete strength (e.g. cube results showing the design strength has been reached). In that case, confirm the anchor design with the actual strength, and do not apply load until the concrete and the anchor have reached full capacity. For chemical anchors, green concrete is also likely to be damp, so use a system approved for water-saturated concrete.