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