2013 Project of the Year - Rehab Honorable Mentions
Oct 28, 2013
Alabama DOT HWY 280 Emergency Storm Sewer Repair
This project, passing under eight lanes of State Highway 280 in Birmingham, Ala., involved the emergency rehabilitation of a 500-ft section of 66-in. CMP storm sewer from manhole to manhole, with an average cover of 65 ft. After the collapse of a junction box, an additional 80 ft of CMP also collapsed — this led to severe flooding and the emergency closure of an exit ramp. Prime contractor Russo Corp. dewatered the sewer and installed pump bypass, then excavated and removed the collapsed junction box and pipe, and installed tunnel plating as temporary shoring. Using centrifugally cast concrete pipe (CCCP) from CentriPipe, subcontractor Utility Asset Management performed spot repair and poured a new invert for smooth sled withdrawal, then relined the interior of all 500 ft of tunnel plating and remaining CMP with 2 plus in. (engineer specified) of CCCP, cast in five end-to-end passes. This created a new, structurally sound, stand-alone pipe that adhered tightly to the original CMP, leaving no annular space. Challenges included minimal staging area and the depth of cover. The 500-ft run of CCCP is the longest completed by the contractor, requiring additional planning to account for friction. Communication between the CCCP sled operator and the team controlling pumping volume and withdrawal speed was difficult. The depth of the pipe ruled out radio, and the noise of the spincaster and the length of the pipe made simple shouting impossible, so the UAM crews used mining cap lamp signals to communicate changes in pumping volume and withdrawal speed. Each 500-ft pass took about 16 hours.
Lake Huron Primary Water Supply System Condition Assessment
Lake Huron Primary Water Supply System (LHPWSS) and Pure Technologies completed a 47-km condition assessment of Lake Huron Pipeline A using advanced non-destructive technologies. The system has about 25 km of non-redundant pipeline, making it very difficult to shut down for inspection and repairs without disrupting water supply to customers. To accommodate operational constraints and continue to provide reliable water supply to its member municipalities, LHPWSS and Pure Technologies used advanced non-destructive free-flowing technologies to inspect the transmission main for leaks, air pockets and structural deterioration while the line remained in service. LHPWSS began its condition assessment project with a leak and gas pocket assessment using SmartBall Technology, a free-flowing tool that identifies acoustic anomalies associated with leaks and gas pockets. The inspection located three leaks and eight gas pockets. Upon verification, the leaks were found to match up with existing features, such as valves and laterals, meaning the Lake Huron Pipeline had no leaks. The gas pockets were verified and likely caused by shutting down and restarting the pumps to insert the inspection tools. After completing a leak detection survey, LHPWSS completed a non-destructive structural condition assessment using PipeDiver Technology, a tool used to identify wire breaks in PCCP. The electromagnetic inspection identified 58 pipe sections with electromagnetic anomalies out of approximately 10,000 pipes inspected, a distress rate of 0.6 percent (industry average is 4 percent). This project provides an example of how utilities can manage aging infrastructure while working within a tight capital budget, effectively extending the useful life of the asset.