Stabilization of Existing Sheet Pile Cell in the Ohio River

• Main Author: Bird, David W.
• Format: Text
• Language: unknown
• Published: Scholars' Mine 2013
• Subjects: Geotechnical Engineering; Long Rock
• Online Access: https://scholarsmine.mst.edu/icchge/7icchge/session03/37; https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=3129&context=icchge

An existing 40 foot diameter sheet pile cell (cell) was used to support a dry fly ash loading platform at an electrical power generating facility on the Ohio River. The cell was designed and constructed in 1986 for support of a coal barge unloading crane but was never put into service. The cell has leaned riverward several inches in the years after construction. Stability analysis indicated a less than adequate overturning factor of safety without any additional loads. The addition of the loading platform could result in an overturning failure. A stabilizing system which provided a horizontal stabilizing force of 750,000 lbs. was developed, designed and subsequently installed. The system included a tension belt steel channel bent about the cell circumference connected to two-1¾inch diameter high strength tension bars at each end. The tension bars extended 100 feet landward and were anchored to two pile caps. The pile caps were supported on a tripod of three-120 ton working load HP14x117 piles driven on a 4:1 batter. The horizontal stabilizing force for the cell originates from four-200 foot long rock anchors (20 foot long bonded length) installed in each pile cap at a nominal angle of 45- degrees from the horizontal. The tension belt channel elongated 3 inches during anchor proof testing while the strand anchors elongated approximately 18 inches. It was necessary to test the anchors in pairs to maintain a balanced loading condition on the tension belt channel, requiring adjusting and balancing the load in the anchors and tension bars continuously to maintain the pile caps in a neutral position. Each anchor proof-test required six hydraulic cylinders and four power packs operated simultaneously at different pressures. After each pair of anchors was proof-tested, the anchors were de-stressed until all pairs had been proof-tested. Then the anchors were reloaded in pairs and locked off at 50% of the 120 ton design load.