Spar and membrane structure

Spar and Membrane Structure (SMS) is a type of wall construction in which lightly reinforced 2" - 3" [5 cm - 8 cm] of shotcrete or gunite skins (membranes) are interconnected with extended “X” shaped light rebar (spars) through the interior of the wall. Typically, SMS construction uses straw bales as leave in formwork for the concrete skins with the spars placed at the head of each bale, however, many other types of formwork could be used in place of straw bales. The SMS system was invented and patented by R. Gary Black, an engineer and professor of architecture at the University of California, Berkeley.