| 摘要 |
<p>An anchoring insert (5), for supporting steps for example, is placed into the wall of a manhole or inspection chamber in such a manner that any hole made during insertion is sealed during manufacture. Apparatus (13) for inserting the insert includes a plurality of separately retractable members (8, 9, 10) which first apply a shaped insert (5) to its correct position, then sequentially retract whilst concrete is applied to form the wall of the manhole or inspection chamber. The wall is thus unperforated in its outer surface.</p> |
