{HEAD ~ A further typical concrete structure} is illustrated in FIG 10 at 28 having buttresses 29 each with {TAIL ~ ducts} 30 
{ HEAD ~ A further typical concrete structure } is illustrated in FIG 10 at 28 having buttresses 29 each with { TAIL ~ ducts } 30
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH