San Elijo Joint Powers Authority Outfall Stabilization Project
Location: Carlsbad, California
This project involved the stabilization of a reinforced concrete outfall pipeline offshore Carlsbad, California. Approximately 2,000 feet of this 48-inch diameter pipeline was precariously suspended above the seafloor and required stabilization. The project site spanned an active surf zone. Environmental restrictions precluded the use of beach or shore-based support systems such as a trestle or pier, and the surf zone was too active to permit the use of floating equipment. L123’s owner, Mark Steffy, conceived and developed the Surf Sled II support system. Steffy also conceived and directed the design of a unique pipe support system. After soliciting 71 engineering firms nationwide, and reviewing a short list of eight responses, the Surf Sled approach was judged by the owner to be the most practical, safe and economical solution. According to the client, the project concept and execution saved the client over $20 million dollars. The surf sled used on this project was the second of three surf sleds designed, constructed and operated by Mark Steffy. The project was the subject of multiple technical papers, articles in trade journals, and presentations.
This project demonstrates the ability of L123 to plan and execute major pipeline work in a nearshore or surf zone condition. It also demonstrates the ability of L123 to conceptualize and execute solutions to challenging underwater project requirements.
Pemex Dos Bocas 24-inch Diameter Outfall Construction Project
Location: Paraiso, Tabasco, Mexico
This project was highly challenging due to the length (2.2-kms) and weight (approx 1,500-tons) of the pipeline, the dynamic coastal environment in which it was installed (coastal surf zone), the offshore water depths involved (excess of 20-m), the substantial project administrative support required by Pemex procedures, and the location of the work to very sensitive nearby existing Pemex pipeline infrastructure (three 36-inch export pipelines and five 48-inch diameter field pipelines). The HDPE outfall pipeline was pre-assembled in ten sections onshore and then pulled offshore in two extended operations (beach-pull). The actual marine installation required extensive around-the-clock operations involving over 250 skilled workers split into two offshore crews and two onshore crews. Final assembly involved fusing together the ten sections, installation of concrete ballast weights, and installation of flotation. The pipeline installation methodology was based on floating the pipeline into position and then flooding and sinking the pipeline. The pipeline was launched from the shoreline using a rail system. Pemex is the Mexican national oil company. ARB-Arendal is a Mexican pipeline company with an American corporate partner. ARB-Arendal performs in excess of $100,000,000 USD of pipeline construction annually in Mexico.