| 摘要 |
A liner for a manhole, inspection chamber or the like comprises superposed sections adjacent ends of adjacent sections being formed in a complementary manner. Each section comprises inner and outer skins joined by a series of spaced webs and a web extending laterally of the webs of the series between the opposite ends of the section. All webs are disposed at right angles to the skins. The arrangement provides a rigid structure capable of resisting pressures placed upon it to a greater degree than hitherto.
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