Construction of pipes

A method of constructing a pipe on a continuous basis, comprising:

• forming a flexible tubular wall structure comprising a radially inner tube, a fibre-reinforced plastic composite, and a radially outer,
• inflating the inner tube to provide form and shape thereto, and
• curing the flexible wall structure to provide the pipe, wherein
• there is a space between the inner tube and the outer,
• the fibre reinforced composite construction comprises reinforcement and a binder and is located between the inner outer,
• the outer serves to resist radial expansion of the inner tube causing it to be subjected to radial compression,
• the radially expanding inner tube operates in conjunction with the outer to cause the volume of the space between the inner tube and the outer to progressively decrease, thereby causing the binder to spread through the space between the inner tube and the outer tube, and
• the outer tube has less resilience than the inner tube so as to yieldingly resist radial expansion of the inner tube.

An elongate hollow structure of composite construction, comprising:

• a radially inner portion, and
• a radially outer portion, wherein the two portions are merged together to provide an integrated tubular wall structure, and wherein
• the radially outer portion is configured as an outer tube of fibre reinforced composite construction including reinforcement,
• the radially outer portion is configured, at least during construction, as a flexible outer casing that serves to resist radial expansion of the reinforcement, thereby causing it to be subjected to radial compression,
• the inner portion and outer tube are spaced apart,
• the fibre reinforced composite construction comprises the reinforcement and a binder and is located between the inner portion and the outer,
• the outer serves to resist expansion of the inner portion causing the inner portion to be subjected to compression,
• the binder is spread between the inner portion and the outer due to the expansion of the inner portion, operating in conjunction with the outer to cause the volume of the space between the inner portion and the outer tube to progressively decrease during the formation of the elongate hollow structure, thereby causing the binder to spread through the space between the inner portion and the outer tube, and
• the flexible outer casing has less resilience than the radially expanding inner portion so as to yieldingly resist radial expansion of the inner portion.