Piles supporting the tower legs, shown at low tide. Note that some of the piles exhibit almost complete loss of section

Rehabilitation of Steel "H" Piles With Advanced Pile Encapsulation Process

During an underwater inspection of the bearing piles supporting electric power transmission towers in Baltimore Harbor, it was discovered that most of the piles had badly corroded from a point approximately one foot below the cap to a depth of four to five feet.

The owner elected to reinforce the piles in the corroded areas by bolting 1/2" thick bent plates to the webs and flanges. A cross sectional view of the bent plate repair is found at the end of this report. To arrest any further corrosion to the piles or the bent plates, the repairs were encapsulated by the Advanced Pile Encapsulation (A-P-E) Process.

PROJECT DATA

Owner: Baltimore Gas and Electric - Baltimore, MD

Contractor: Mid Atlantic Diving Contractors - Ellicott City, MD

Materials:
Steel Plates: Dura Bond - Export, PA

Encapsulation: Advanced Pile Encapsulation Process, Master Builders, Inc. - Cleveland, OH


After the translucent FRP jackets were installed around the piles and bent plates, A-P-E Pile Grout was pumped into the space between the steel members and the FRP jacket. The grout was batched, mixed and pumped by the plural component method, as shown in the schematic blow. The reactive components of the grout were pre-mixed with inert silica filler and pumped through separate hoses to the final mixing chamber, where they were blended just prior to entering the FRP jacket. This method greatly reduces the problems normally associated with handling pre-mixed or "hot-potted" epoxy grouts in the field. Because the materials in the mixers, hoppers, and hoses are not catalyzed, the equipment can be cleaned with water, virtually eliminating the need for solvents and their effects on the environment.

The grout was introduced into the jacket from the bottom up, through strategically placed injection ports. The progression of the grout was visually monitored through the translucent jacket to insure that all the steel surfaces were completely surrounded by the protective polymer grout.

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