Concrete construction, prestressed concrete: Holes and grout for post-tensioned prestressed concrete high tension cables and anchors. These are evident at both slabs and both column faces. Horizontal hollow tubes are placed in the slab and column forms so they are embedded in the slab and column CIP concrete. High tension post-tensioning steel cables are threaded into the tubes. Other reinforcing is placed, and the concrete is then cast in place in the forms. After the slabs have attained high strength, tensioning jacks are placed horizontally at one or both ends of a cable, the jacks push against the slab/ column concrete and pull on the cables, which develops compression in the concrete and high tension in the cables.The compression counteracts tension in the concrete slab from carrying its own concrete weight plus loads placed on the slab. The cables are anchored at their ends, back into the hole. The small cavities in the slab/ column left at the end of the cables is filled with cement grout, which is a mixture of concrete, sand, and water. In this photo, post-tensioning has been completed, and grouting has been completed for all cable ends except those on the face of the upper portion of the column. A close look at the ungrouted holes shows cable ends in a couple of the holes. Wilshire Blvd, Westwood, Los Angeles, CA, 2004.

Concrete construction, prestressed concrete: Holes and grout for post-tensioned prestressed concrete high tension cables and anchors. These are evident at both slabs and both column faces. Horizontal hollow tubes are placed in the slab and column forms so they are embedded in the slab and column CIP concrete. High tension post-tensioning steel cables are threaded into the tubes. Other reinforcing is placed, and the concrete is then cast in place in the forms. After the slabs have attained high strength, tensioning jacks are placed horizontally at one or both ends of a cable, the jacks push against the slab/ column concrete and pull on the cables, which develops compression in the concrete and high tension in the cables.The compression counteracts tension in the concrete slab from carrying its own concrete weight plus loads placed on the slab. The cables are anchored at their ends, back into the hole. The small cavities in the slab/ column left at the end of the cables is filled with cement grout, which is a mixture of concrete, sand, and water. In this photo, post-tensioning has been completed, and grouting has been completed for all cable ends except those on the face of the upper portion of the column. A close look at the ungrouted holes shows cable ends in a couple of the holes. Wilshire Blvd, Westwood, Los Angeles, CA, 2004.