Cummins Cederberg provided marine engineering and construction support services to support the design-build of the Berth 7 Bulkhead Replacement project at the Kingston Wharves terminal. The project included reconstructing 600 ft. of wharf at Port Bustamante for Berth 7 to align with the waterward extent of Berth 8 and incorporate a return segment to meet the existing bulkhead location of Berth 6. The berth improvements included a new pipe pile bulkhead with a raised cap elevation of +8.75 mean sea level (MSL) to accommodate a future dredge depth of -50.0 ft.

Our engineering team conducted a site inspection to evaluate design conditions, construction access, sequencing, and other potential considerations that might impact the design or the final operations. Following the site visit and review of available documentation, the engineering team prepared conceptual designs and drawings.

The design criteria accounted for a seismic event with a 475-year return period. The 4-foot diameter pipe pile bulkhead is anchored with 3-in. diameter, grade 80 tie rods to a continuous steel sheet pile wall buried 130 ft. upland, behind the pre-existing anchor system. The pipe piles are 105 ft. in length to account for the future dredge depth and underlying soft alluvium deposits of the harbor. The new bulkhead cap utilized 6,000 psi concrete.

The design accommodates a vessel size of 105,000 deadweight tonnage (DWT), factoring in wind speeds up to tropical storm force and a 130-foot-wide, 14-in. concrete apron supported by a gravel subbase was designed behind the new bulkhead for the full length to accommodate straddle carriers and mobile cranes with wheel loads up to 15 tons and outrigger pressures over 6,000 psf.

The pre-existing bulkhead was built by the British in the 1960s and utilized clean, well-graded granular backfill. This fill was found to be in pristine condition and able to be reused for the new apron subgrade. Due to the soft nature of the in-situ soils, up to 4 meters of dredging were required in the 50-foot-wide gap between the old and new bulkheads for soil improvement. Local river shale cobble stone was used to backfill the gap above the water level.

Utilities include high-mast lighting, storm drainage and fire protection. The fire pump draws seawater from the harbor through a 3-foot diameter intake pipe. Drainage outfalls also measured up to 3 ft. in diameter. The light masts provide illumination from 100 ft. above the wharf and are designed for 150 mph winds. The port was struck by a magnitude 5.4 earthquake in late 2023. No damage to the newly constructed berth was reported. The facility opened January 2024.