Pipe Rehabilitation _ Steel Liners NY Siphon-Blue Ridge GA-McCook-Silver Lake CA

Abstract; Pipe Rehabilitation and Steel Tunnel Liner showcase provides a photographic presentation of installing a 72 inch steel siphon tunnel liner under New York Harbor, rehabilitation of a 168 inch diameter riveted steel penstock under a TVA dam in Georgia and installing a 96 inch diameter steel tunnel liner for Los Angles Depart of Water and Power (LADWP) in California. This slide show provides commentary, photographs and methods utilized for these tunnel liners and includes other liner/rehabilitation projects. 

This presentation show cases installing a 72 inch diameter steel pipe within a newly installed 9500 foot long precast segmented concrete tunnel casing which extended from Staten Island to Brooklyn New York. Due to undulations in the tunnel elevations the tunnel liner height ranged from a height of 17 to 21 inches above the tunnel invert which had to be accommodated with the installation methods and pipe support methods. The planning and design of the steel tunnel liner installation changed as mining progressed due to a drifting alignment plus hurricane Sandy in  2012 submerged the entire operation.

The TVA Blue Ridge Dam penstock rehabilitation consisted of two primary components.   Dam and Intake structure stabilization and installation of a new penstock liner.  The permanent remedy for the penstock rehabilitation was to install a 147 inch steel liner within the existing 168 inch riveted steel penstock. National Welding Corp was hired by Garney Companies to perform most of the penstock specialty work and Northwest Pipe provided the penstock and materials.  The initial task required removing a 300 ton concrete filled steel girder within the penstock which was accomplished using oxygen lances. This cleared the way to install a new steel liner within the aging riveted steel liner.  Each new pipe segment weighed approximately 50,000 pounds and was required to be transported through an existing penstock with an irregular floor surface and as little as 8 inches annular clearance. Large reducers were used to connect the new liner to the existing penstock. National devised a pipe transportation system which could carry the pipe approximately 1000’ through the penstock then position the pipe segments within the existing penstock.

The LADWP steel liner show cases installing a 96 inch x .563 inch x 3200 foot butt welded steel tunnel liner within a newly installed precast segmented concrete tunnel casing under Griffith Equestrian Park to the Silver Lake Complex.  The steel pipe sections were mortar lined and coated which added considerable weight to the pipe and challenged the installation methods.

Other pipe and tunnel rehabilitations are also included in this presentation.