The present method includes casting a poured concrete liner in an existing manhole with a protective acid resistant plastic material covering the interior surface of the newly poured concrete liner. A plurality of arcuate form panels are assembled into a circular form spaced radially inwardly from the...http://www.google.fr/patents/US5032197?utm_source=gb-gplus-shareBrevet US5032197 - Cast-in-place manhole liner method
