Noble Consultants performed a preliminary engineering and construction cost assessment for the repair and rehabilitation requirements for G-P Gypsum’s Berth D-46 Port of Long Beach facility. The purpose of NCI’s services was to provide recommendations regarding the most economical approach to maintain the plant’s bulkhead protection, rehabilitate the deteriorated wharf fender system, and restore project depths within the bulk carrier berth.

The G-P Gypsum Berth 46 plant receives deliveries of gypsum ore by bulk carrier on a monthly basis. The existing berth is 640 feet long with an existing depth of -31 to -33 feet MLLW that requires dredging in order to deepen to a projected depth of -38 to -40 feet MLLW. NCI evaluated dredging methods, disposal alternatives, dredged channel stabilization retention structures, permit requirements, and opinion of construction costs. In addition, NCI evaluated alternative designs and construction methods including opinion of construction costs to replace the wharf’s deteriorated fender system and to rehabilitate and replace its deteriorating bulkhead system.

NCI initially evaluated alternative replacement bulkhead designs, and then performed the final engineering design and preparation of construction drawings and specifications for the selected alternative. This replacement bulkhead consisted of a coal tar epoxy coated steel sheet pile bulkhead driven into a very hard bottom. The bulkhead was anchored by use of a double corrosion protected Dywidag tie-rod system secured to the sheet piles by use of a double steel channel waler, and anchored on the landward side by an anchor system consisting of tension and compression steel H-piles with a reinforced concrete cap per each tie-rod. The tension piles also incorporated drilled/grouted Dywidag rock anchors for additional tension capacity. A reinforced concrete cap encased the steel channel waler and top of sheet piles. This new bulkhead was installed directly outboard of the 50-year old existing bulkhead prior to construction of the new County harbor patrol headquarters building and other site improvements. NCI also provided construction support services throughout the bulkhead’s construction.

NCI performed the engineering design for replacement of a 500-foot timber pile bulkhead. Services included a site and geotechnical investigation; topographic and boundary survey; feasibility analysis of alternative construction materials and methodologies; final design; and preparation of plans, specifications, contract documents and construction cost estimate. The improvements included a tied-back concrete sheet pile bulkhead, public promenade, landscaping, drainage and repavement of the parking lot.