Abstract: A pipe connector structure, for coaxial pipe sections having a common liner, and including a pair of flange members, constructed to be drawn together by suitable bolt or other attachment means, which flange members include flange bodies having remote flange ends that are inwardly and downwardly tapered and constructed to coact with pipe securement rings. Between such rings is a sleeve, split in two halves along a diameter thereof for positionment about the liner and constructed, if expanded radially outwardly by radial expansion of the liner, upon the application of internal pressure means, to come in contact with the inner surfaces of the machined flange members to delimit such radial expansion. Alternatively, where the liner is essentially non-radially expandable, then gaps in the split sleeve can be closed and such sleeve and flanges can act conjointly as to the liner to counteract radial liner burst pressures. Pipe ends to be coupled together are positioned against interior shoulders of the split sleeve.