Reinforced concrete structure construction: Basement construction using shotcrete applied reinforced concrete. Shotcrete is being applied to upper half of wall at left center, with one worker spraying shotcrete and the other cleaning off over-shot/excess that accumulates on back form and reinforcing steel. Worker at mid-right is troweling upper half of shotcrete wall, creating a smooth finish. Between the two, at mid photo, is shotcrete equipment, consisting of concrete mixer delivering the shotcrete/concrete mixture and the concrete pump and air compressor spraying the shotcrete/concrete.
In background is basement exterior wall. The right side is of shotcrete reinforced concrete. The left side has back form and steel reinforcing steel, waiting for application of shotcrete to complete the wall. Scaffold is in place to support the shotcrete team. Beyond the shotcrete wall on right is temporary soil support structure: steel H-section soldier beams supporting timber breastboards with additional support from steel tiebacks anchored at far end in soil. On left side, soil for upper half of excavated wall has been sloped back to angle of repose of undisturbed soil. The vertical wood forms at various points supported on one side by diagonal braces are backforms for shotcrete. Pallazo, Westwood, Los Angeles, California, January 2006.

Reinforced concrete structure construction: Basement construction using shotcrete applied reinforced concrete. Shotcrete is being applied to upper half of wall at left center, with one worker spraying shotcrete and the other cleaning off over-shot/excess that accumulates on back form and reinforcing steel. Worker at mid-right is troweling upper half of shotcrete wall, creating a smooth finish. Between the two, at mid photo, is shotcrete equipment, consisting of concrete mixer delivering the shotcrete/concrete mixture and the concrete pump and air compressor spraying the shotcrete/concrete.
In background is basement exterior wall. The right side is of shotcrete reinforced concrete. The left side has back form and steel reinforcing steel, waiting for application of shotcrete to complete the wall. Scaffold is in place to support the shotcrete team. Beyond the shotcrete wall on right is temporary soil support structure: steel H-section soldier beams supporting timber breastboards with additional support from steel tiebacks anchored at far end in soil. On left side, soil for upper half of excavated wall has been sloped back to angle of repose of undisturbed soil. The vertical wood forms at various points supported on one side by diagonal braces are backforms for shotcrete. Pallazo, Westwood, Los Angeles, California, January 2006.