An aerial portion of the Blue River interceptor crossing Brush Creek just north of Chelsea Avenue in Kansas City, Missouri, collapsed on July 14, 2016. The failure of the cast-in-place arched reinforced concrete interceptor is believed to be the result of a pier failure. Immediately following the collapse, on-call emergency responders were mobilized to establish a bypass pumping system to limit bypasses to the creek. The emergency response also included an engineering survey and a geotechnical investigation. In order to facilitate a timely repair of the interceptor, the Water Services Department (WSD) chose to complete the project using the design-build delivery method.
In combination with Leath & Sons, Burns & McDonnell designed and constructed the repairs. Our team’s repair approach included replacing the entire aerial portion of the interceptor, approximately 375 linear feet. The team also installed a 72-inch steel pipe that was mounted on piers and supported by drilled shafts. For maximum rigidity and to limit the number of supports necessary, the wall of the pipe is three-quarters of an inch thick. The pipe was lined and coated with a ceramic epoxy for corrosion protection. The team constructed the piers and drilled shafts using reinforced concrete that were keyed into the underlying shale layer for support against anticipated loads. Steel saddles connected the pipe to each pier. Our team designed the saddles to allow longitudinal movement to accommodate anticipated expansion and contraction with a single expansion joint included in the assembly. The saddles were also designed to prevent flotation since this crossing is located below the 100-year flood elevation.
The replacement pipe joined the existing arch sewer at a junction structure constructed on each end of the creek crossing. The upstream structure was oversized to accommodate removal of rock and grit from the flow stream. The disturbed area in the vicinity of the aerial crossing was protected with a layer of rip rap.