Miscellaneous # 1988 Bath
The theory and experimental behaviour of solid skin/foam core PVC composite pipes is discussed.
Experimental load testing for periods in excess of 10,000 hours has been conducted and the influence of the ratio of skin/core sections examined within the programme to evaluate long term design properties for external loading.
The use of solid wall thermoplastic pipes for buried installations has been well documented over a period exceeding 30 years of practical installations.
The long term behaviour of such materials has been extensively researched and established by many authors.
Opportunity exists for optimising polymer useage by location of material to the zones of highest fibre stress in the pipe cross-section.
One method of this is the application of foam core/solid skin PVC pipe made under controlled foaming conditions.
This technique has now being widely used for buried pipelines in diameters up to 400mm in various countries.
Composite sections offer the potential to optimise polymer use in load bearing applications by relocating the higher strength materials to the zones of maximum fibre stress in the section.
This may be achieved by a number of classical treatments such as metal skin/polymer core or metal skin/foam core or polymer skin/polymer foam core combinations.