60" and 48" Manhole Repairs

Project Location
Garden Shadows Ln – Cypress, TX
Construction cost
Construction Start/End
12/2015 - 01/2016


  • 60” RCP Manhole with (2) 10” Force Mains, 27 VF – walls were fully deteriorated
  • 48” RCP Manhole, 27 VF
Depth of structure:
2 manhole 27 VF each
Health and safety:
Used conventional confined space entry program
Has any re-inspection been performed? What was the condition of the structure?

Alene Efaw
Brown & Gay Engineers, Inc.


a) This project was deemed an Emergency because 48” manhole had collapsed creating a sinkhole in the surrounding soil. Prior to installation of the Danby liner, the contractor had to bypass 1 of 2 10” force mains and excavate the remains of the manhole out. The contractor installed 27 VF of 8’ ID liner plate, then reconstructed the manhole with a double mat of rebar and proceeded to install Danby PLIII 1” flat panels (3½) 8’ vertical sections. The (2) 10” force main were reconnected using a custom fabricated 24” HDPE force main drop. An 8’x8’x18” thick concrete HS20 load rated manhole lid was also constructed with the underside having the corrosion resistant Danby PVC liner.

b) A 48” manhole was rehabbed using Danby PLIII ½” profile spiral wound method. A 5’x5’x18” manhole lid was constructed with the underside having Danby PVC liner.

This project was done by Boyer, Inc. of Houston, TX

Method of flow bypass or diversion, if used:
By-pass of (1) 10” Force main, Internal by-pass for the 2nd 10” Force main directly to the 18” downstream line


Problems encountered during construction:
Problems encountered after construction: