Underground equipment chamber access opening has metal frame with prefabricated concrete surround sealed in opening

摘要

The access opening for an underground chamber (1) designed to be fitted with a cover (7) set in a metal frame (8), has a surround (9) of concrete or other prefabricated material, fixed to the metal frame in the workshop. The surround is designed to be fitted into the chamber opening (6) formed by its vertical walls, and sealed to the walls to create a non-deformable seat for the metal frame. The surround is made with a stepped surface to fit in the opening formed by the upper edges of the chamber walls, and the metal frame has an S-shaped cross-section with one edge projecting slightly above the concrete surround to receive the cover.