The first phase of the Wagener Avenue repair project consisted of surveying and videoing the existing site conditions. Forsberg Engineering and Surveying, Inc. provided a topographic survey of the surface conditions as well as a video of the existing vitrified clay pipe storm drainage system. Based on the video, it was evident that making spot repairs of the existing storm drainage system was necessary before repairs on the entire pipe run (from Dunneman to 3rd Avenue) could be initiated.
A contractor was hired to investigate the areas of pipe collapse or blockage. These areas closely matched the location of surface sinkholes and the presence of steel plates. The contractor excavated the pipe at each of the identified locations. Due to the number of conflicting utilities and the depth of the storm drain (up to 13 feet), trench boxes had to be used to provide worker safety and provide support of the adjacent street and utilities. As each location was repaired, a video inspection was performed to assure the City that the repair eliminated the problem.
Once all of the repairs were completed, Forsberg again surveyed the system and developed plans and specifications for lining of the entire pipe. This lining process is called cured-in-place pipe (CIPP). The system uses a liner that is pulled through the pipe (from manhole to manhole). Then the liner is expanded by use of mandrels or steam to conform to the pipe shape. Once the liner is in place, steam or another catalyst is used to solidify the liner. This CIPP process will prevent future joint and pipe failures and extend the life of the existing system without having to excavate the entire street – resulting in a cost-effective, less disruptive means of repairing the pipe.