8 IDR June/July 2019 www.dredgemag.com
Moore, these coconut coir logs are 100 percent biodegradable as was required by the Corps. The densely packed coconut fibers are covered in a biodegradable natural fiber netting instead of the usual plastic netting. The logs will degrade in place within about a year. Another 5-acre location to the north is act- ing as a control area for the project. Scientists from Georgia Southern University and the University of South Carolina will monitor the placement and control areas for a two-year pe- riod to see how long it takes for the marsh grass to regenerate and how it performs in the future in the higher elevation. "They will be monitoring vegetation to see how quickly the marsh recovers. They have done many similar investigations and studies, not with the Corps, but for marsh health moni- toring in general. We hope to be able to use this method for coastal resiliency and sea level rise as something that could augment other low-lying coastal areas," Moore said. JIA and The Nature Conservancy purchased an elevated monitoring camera system to pro- vide imagery of the project to the public as it progresses. Once work is completed on the Jekyll Creek portion, the Rockbridge and associated equipment will be moved further down the AIWW for regular maintenance dredging at Fields Cut, Hell's Gate and Buttermilk Sound areas in both Georgia and South Carolina. Material from Field's Cut will be placed in Jones Oysterbed Disposal Area adjacent to the channel. The Hell's Gate material will be placed on Tract 15 and material from Buttermilk sound will be placed in Tract 42 B or Tract 43. The areas will be dredged to -12 feet MLLW with a 2-foot allowable overdepth and up to one verti- cal on three horizontal side slopes. Dredging of these areas is expected to be completed in Sep- tember.
Dredge Yard Delivers Ball Joints for Capital Project in the Middle East
BY ANNA TOWNSHEND In early 2019, Dredge Yard, based in The Netherlands, delivered a second batch of 50 heavy-duty dredge ball joints to a customer in the Middle East. Dredge Yard delivered the first group of ball joints in late 2018, for a capital dredging project already in operation in the Gulf region. The ball joints are joining pipeline that covers about 1.5 kilometers (about 0.93 miles). Dredge ball joints are used as a flexible con- nection or coupling between steel pipelines. "Steel pipelines need flexible connections for two reasons. First, it is a floating pipeline, which is exposed to many natural forces, such as waves, currents, wind, etc. Therefore, it must be flexible in order to endure the movement and natural forces under different operation conditions," said Michel Debo, Dredge Yard operations man- ager. Secondly, cutter suction dredges that use pipelines must swing in all different directions, and the pipeline must mimic the same flexibility. Ball joints also function during dredging op- erations as easy coupling and discoupling con- nection points in the pipeline, allowing the contactor to shorten or lengthen the pipeline as need, as the operation moves closer and farther from the discharge area. The ball, which is placed inside the dredge ball joint casing, is what gives the pipeline its flexibility and allows it to tilt in all directions. A dredge ball joint is made of many different parts - the case, ball, gland, liner and seal. Each part is manufactured individually and joined to- gether. The liner and rubber seal are mounted on the case. Then, the ball is placed in position and locked using a gland (locking ring). View an animation of this process here: https://youtu. be/6Zl4beHi8iA?t=101. Debo said the case and ball are made of car- bon steel, providing high elongation and impact value. The gland is made of chromium, nickel and a molybdenum alloy, providing high tensile, high yield and high hardness value. The liner is made of ductile manganese iron or hard chro- mium iron for wear resistant properties. The seal is an NBR 70. "The production of ball joints begins by cre- ating patterns made of aluminum or hard wood, in order to ensure that all parts cast are identical and interchangeable," Debo said. After casting, the components are heat treated to Interna- tional Organization for Standardization (ISO) and American Society for Testing and Materials (ASTM) standards. He said the heat treatment achieves the me- chanical properties required for international standardization. "More specifically, heat treat- ment changes the properties of the material (for example, making it harder, more durable), until it reaches the standard international require- ments. This ensures ball joint durability and quality," Debo said. Each dredge ball joint is cast in the required shape with extra machining allowance. A high accuracy vertical CNC machine is used to shape each component. "The CNC machine is neces- sary to provide accuracy, ensuring that each part is identical and interchangeable," Debo said. This process will also smooth the surface of each component for low friction operation. It took about three months to machine 50 dredge ball joints. Dredge Yard manufactures the part at its manufacturing facility in collabora- tion with its partners in the Republic of Turkey. Dredge Yard and some third-party operations then perform a number of quality control tests. The chemical composition and mechanical properties tests are performed by a third party. Dredge Yard also performs measurement tests of all dimensions after casting and after machining. It runs a hardness test and assembly test for all parts. Additional testing includes ultra-sonic test- ing for 20 percent of all surfaces, magnetic par- ticle tests and dye penetrant inspections, which are used to make sure that the casing material meets quality standards. A surface roughness test ensures that the surface is smooth enough to al- low optimal flexibility in the pipeline. A locking fix and release test on multiple joints inspects the functionality of the locking ring (gland) by locking and unlocking it.
Dredge Yard delivered 50 dredge ball joints for ongoing dredging work in the Middle East.
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