Abstract: An elongate hollow structure and method of constructing the hollow structure is described, whereby the hollow structure includes a radially inner portion and a radially outer portion adapted to be merged together to form a tubular wall structure. The method includes providing the radially inner portion, providing the radially outer portion about the radially inner portion, wherein a space exists between the radially inner and outer portions, the space containing a gas therein, and expanding the inner portion. The gas within the space between the inner and outer portions is arranged to be expelled as the inner portion is expanded.

Abstract: A compression apparatus (10) for compressing a tubular structure (12) to be formed into a hollow structure (20) such as a pipe comprises contact elements (60) arranged in two sets, (61, 62). The contact elements (60) are adapted to move along a compression section (41) in a coordinated sequence, whereby a portion (12a) of the tubular structure (12) within the compression section (41) is compressed between pairs (63) of opposed contact elements. The apparatus (10) includes registration means (110) for causing respective pairs (63) of opposed contact elements (60) to be maintained in registration with each other while moving along the compression section (41).

Abstract: An elongate hollow structure and method of constructing the hollow structure is described, whereby the hollow structure includes a radially inner portion and a radially outer portion adapted to be merged together to form a tubular wall structure. The method includes providing the radially inner portion, providing the radially outer portion about the radially inner portion, wherein a space exists between the radially inner and outer portions, the space containing a gas therein, and expanding the inner portion.

Abstract: An elongate hollow structure and method of constructing the hollow structure is described, the hollow structure including a radially inner portion and a radially outer portion merging together to form a tubular wall structure. The method includes providing the radially inner portion, assembling the radially outer portion about the radially inner portion, and radially expanding the inner portion. The outer portion comprises an outer layer of fiber reinforced composite construction surrounded by a flexible outer casing. A space is provided between the radially inner portion and flexible outer casing. The outer layer includes reinforcement and a binder. The flexible outer casing resists radial expansion of the reinforcement, subjecting it to radial compression. The radially expanding inner portion cooperates with the flexible outer casing to cause the volume of the space to progressively decrease, causing the binder to spread through the space between the radially inner portion and flexible outer casing.