Precast Manholes

Precast circular concrete manholes are used in sanitary sewer and storm drain systems for access, observation and junctions. Precast circular vertical structures are used for pump stations, wet wells, stormwater management structures, and impoundment overflow structures. All manholes and vertical structures can be provided for highway, railroad or aircraft loading. Precast circular manholes and vertical structures are normally available in diameters of 48 inch through 126 inch.

Precast circular manholes can be used for the following:
• access to the system for maintenance
• observation points
• changes in pipe size
• changes in pipe shape
• changes in direction of pipe
• junctions for multiple pipes.

Precast circular vertical structures can be used for the following:
• wet wells
• sanitary or stormwater pump stations
• stormwater management or best-management-practice structures
• overflow structures for ponds.

Precast circular manholes and vertical structures can be provided with the following features:
• precast invert channels
• protective linings
• flexible watertight pipe-to-manhole connections
• custom openings
• custom tops.

The following joints are normally available for precast circular manholes and vertical structures:
• single offset with profile rubber gasket
• confined o-ring rubber gasket
• pre-formed mastic or butyl gasket

The following specifications apply to precast circular manholes:
• ASTM C478 / AASHTO M199 - Precast Reinforced Concrete Manhole Sections
• ASTM C443 - Joints for Circular Concrete Sewer and Culvert Pipe Using Rubber Gaskets
• AASHTO M198 - Joints for Circular Concrete Sewer and Culvert Pipe Using Flexible Watertight Gaskets
• ASTM C923 - Resilient Connectors Between Reinforced Concrete Manhole Structures and Pipes
• ASTM C1244 – Standard Test Method for Concrete Sewer Manholes by the Negative Air Pressure (Vacuum) Test.

N/A, P.O. Box 569470, Dallas, TX 75350-9470. Tel: 972-262-3600; Fax: 972-264-6236.