Manhole Rehabilitation Research for WERF
Failure of a manhole may have catastrophic consequences such as a sinkhole. At a minimum, wastewater flow will be blocked and flow upstream of the manhole will back up, causing a sanitary sewer overflow (SSO). Accordingly, the structural condition of a manhole is an important performance indicator and risk of failure should be minimized. Mechanical strength of manhole rehabilitation materials vary substantially, and little is known about their ability to withstand the dead and live loads exerted on a manhole. As such, this project investigates the structural capabilities of commonly used manhole rehabilitation materials and methods via literature review, case study compilation, lab tests on mechanical strength, and computational modeling.
A classification for manhole rehabilitation techniques was provided based on their structural capabilities (i.e., fully, semi, or non-structural). The results of this project suggest that any type of manhole rehabilitation material can be applied as fully structural; nevertheless, it may be difficult to achieve the thickness required to qualify as fully structural for the spray-applied, cured-in-place type liners. A user-friendly decision support tool was also provided along with this report as a practical tool to choose structural class and construction methods appropriate for a manhole considered for rehabilitation.