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A sanitary manhole under construction. A sanitary manhole (sewer manhole, [1] sanitary sewer manhole [2] or sewer maintenance hole [3]) is a manhole that is used as an access point for maintenance and inspection of an underground sanitary sewer system. Sanitary manholes are sometimes used as vents to prevent the buildup of pressurized sewage ...
Manhole closings are protected by a grating or manhole cover, a flat plug designed to prevent accidental or unauthorized access to the manhole. These covers are traditionally made of metal, [2] but may be constructed from precast concrete, glass reinforced plastic or other composite materials (especially where cover theft is of concern ...
A round manhole and its cover. A manhole cover is a removable plate forming the lid over the opening of a manhole, an opening large enough for a person to pass through that is used as an access point for an underground vault or pipe. It is designed to prevent anyone or anything from falling in, and to keep out unauthorized persons and material.
Even though years of experience accounts for a good gauge for the appropriate lifting anchor to be used, it should not be left to the reinforcement fabricators and precast factory personnel to select the lifting anchor. The design engineer should specifically account for the applied loads expected during the lifting, transport and placement (or ...
Precast concrete is a construction product produced by casting concrete in a reusable mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples include precast beams, and wall panels, floors, roofs, and piles.
The concrete step barrier in the under construction M8 motorway in Ireland (August 2008) With effect from January 2005 and based primarily on safety grounds, the UK National Highways policy is that all new motorway schemes are to use high-containment concrete barriers in the central reserve. All existing motorways will introduce concrete ...
Pre-tensioned concrete is a variant of prestressed concrete where the tendons are tensioned prior to the concrete being cast. [1]: 25 The concrete bonds to the tendons as it cures, following which the end-anchoring of the tendons is released, and the tendon tension forces are transferred to the concrete as compression by static friction.
Autoclaved aerated concrete (AAC) is a lightweight, precast, cellular concrete building material. Developed initially in the mid-1920s, it has expanded into widespread use. Developed initially in the mid-1920s, it has expanded into widespread use.