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Training Manholes

Worksheet in progress

A code of practice for the structural analysis of manholes is being prepared by the DWA, and we are actively involved in it (committee work). We have been preparing static calculations for circular manholes since 1997 - consistently, for all materials including reinforced concrete.

The dimensioning is based on a vertically placed pipe (see trenching) with engineering additions. Circumferential and longitudinal directions are to be considered; often buoyancy control is required.

Topic Overview

Basics of buried pipes (refreshed)

Geometry of the manhole

  • Manhole lid with cover construction or cone
  • Manhole pipe (shaft pipe)
  • Shaft bottom construction, upstand (raised edge), foundation

Installation situation and bedding, bedding stiffness

Manhole pipe-soil system

Openings and nozzles for inlets and outlets

Non-uniformity factor radial, support factor axial


  • Manhole lid
  • Shaft casing
    - Radial (circumferential, horizontal)
    - Axial (longitudinal, vertical)
    - Shell buckling
  • Thrust (shearing)
  • Shaft bottom: bending


Positional restraint against uplift, buoyancy in case of groundwater