Annual Wastewater Manhole Rehabilitation Program
Project Number 01-476-009
The City has awarded this project to
Quest Civil Constructors Inc.
TProject is complete.
Construction on this project began at the end of April 2012 and
is expected to be completed by March 2013.
The City of Mesa maintains
approximately 31,700 manholes in its wastewater collection
system. The majority of these manholes are constructed of
concrete or brick. Due to the corrosive environment of
wastewater, these materials can deteriorate over time.
This deterioration occurs more rapidly in lines that are larger
in diameter (15-inch and larger). These larger lines are
typically the main collection lines in the system, where
wastewater is in the lines longer for conveyance to treatment
plants and where more turbulence occurs due to other lines
joining the system.
Currently, new manholes for these
size lines are installed with state-of-the-art coating systems
that may extend their service lives over 20 years.
However, the City has older manholes that were not installed
with the new coatings. The deterioration of the concrete or
brick can affect the structural integrity of the manhole and,
ultimately, the street above the manhole. City Staff
inspects the existing manholes on wastewater main lines
periodically to identify manholes that are deteriorated to the
point where they must be rehabilitated with repairs and
coatings, or replaced. 550 manholes have been rehabbed
since 1996 with 233 being completed in the last 5 years.
This project will rehabilitate an
additional eighty (80) deteriorated manholes. The existing
concrete is cleaned, and any structurally deficient concrete is
removed. New concrete is then bonded to the existing
concrete, restoring the manhole to its original dimensions.
Other areas of the manhole in need of repair are also
rehabilitated (bench, adjusting rings, frame and cover, etc.).
The manhole is then coated with a corrosion resistant epoxy
coating that protects the manhole from the corrosive action of
The recommended total award of this
project is $777,378.80 which consists of the lowest
bid of $706,708.00 plus an additional $70,670.80 (10% allowance
for change orders).