said pipe being cylindrical, and formed of a strip of {HEAD ~ material} of {TAIL ~ uniform thickness} which enables the pipe to withstand compressive loads experienced by culverts in the ground, 
of
said pipe being cylindrical , and formed of a strip of { HEAD ~ material } of { TAIL ~ uniform thickness } which enables the pipe to withstand compressive loads experienced by culverts in the ground ,
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH