One of Springfield’s main outfall pipes—an 84-inch, 100-year-old brick pipe—was failing due to poor soil conditions, high groundwater, and heavy use. Sections of the pipe were losing courses of brick and in danger of collapse.
Poor soil and groundwater conditions provided challenges to the design of dewatering/groundwater cut-off, support of excavation, and pipeline support. Proximity to existing flood controls structures—including flood gates and a flood control dike—required frequent coordination with regulatory agencies and also required a variety of construction techniques, including trenchless rehabilitation and open-cut pipe replacement.
Kleinfelder performed a structural assessment using Closed Circuit Television technology and manned entries, which identified the sections requiring replacement or rehabilitation. The team designed replacement sections using 84-inch, fiberglass-reinforced pipe for scour and hydrogen sulfide protection. In order to avoid disturbance to resource areas and the existing flood control system, cured-in-place pipelining was used to rehabilitate some sections. The project also included replacement of large CSO regulator and flood control structures.
Rehabilitation and replacement of these sections protected a critical piece of infrastructure from collapse. The project identified a problem with the owner’s infrastructure and integrated a solution to this operations and maintenance failure with solutions addressing the owner’s CSO control and capacity issues—a dual benefit.