Commercial diving is likened to visiting an alternate world, albeit one with a host of dangers associated with both the profession and the environment. At the Military Ocean Terminal Concord (MOTCO) in California, KCI engineer-divers combined comprehensive safety procedures with their technical knowledge and skills to address those risks and evaluate the condition of the facility’s expansive waterfront pier structure.
Jutting into Suisun Bay, MOTCO’s ship-loading and unloading complex (originally known as Port Chicago) was built in the 1940s to support military operations during World War II. Nearly three miles of pier with embedded railroad tracks carry payloads directly to warships at dock. Beneath lies a forest of more than 15,000 mostly-timber piles in water ranging in depth from two to 41 feet.
“The piers were built using 19th century technology but have to meet the needs of 21st century missions,” said KCI project manager John M. Hudacek, PE. The Army’s 834th Transportation Battalion funnels nearly a quarter of the military’s ordnance supplies through MOTCO each year.
Over the last three years, engineer-divers from KCI and joint venture partner Pennoni Associates Inc. have completed five assignments at the facility—the first three to conduct routine condition inspections for each of the three major piers, the last two for more in-depth investigations based on previous findings.
Although we have prior experience with major waterfront facilities, the MOTCO project, at a combined fee of $1.6 million, is by far one of the largest underwater inspection assignments ever undertaken by our Transportation Structures Practice.
John M. Hudacek, PEPractice Leader
Each three-to-four week excursion required extensive preparation, and safety was a critical component in all facets of planning and onsite inspection. Dive staff were involved in every aspect of job safety, including preparation of a detailed dive safety plan and job hazards analysis that covered all aspects of both the underwater and topside work.
Before each of the five trips, three engineer-divers flew out a week ahead of other team members to procure, prepare and set up all of the inspection and dive gear/equipment, most of which had been certified and shipped out from the East Coast. They also pre-labeled all substructure units on the underside of the pier, performed a condition inspection of topside deck elements, and conducted a cursory safety assessment of the pier to flag potential hazards to the incoming full dive team.
“In addition to a diver retrieval drill [see photo above], we held safety briefings on site to start each day, as well as at the end of each dive,” said dive team leader J. Ikaika Kincaid, PE. “The remains of Pier 1 and the nearby national memorial [see inset below] were a constant reminder that safety needed to remain foremost in our minds.” In 1944, a massive explosion during ship-loading operations killed more than 320 sailors, wounded another 400, destroyed three ships and later became the impetus for developing safety regulations for loading and unloading ordnance.
Once the full crew was on site, dive teams followed a rotation schedule to ensure that different engineers were in the water for each multi-hour dive. Staff worked 10 hours each day, seven days-a-week to focus on only one pier during each tour.
“This was a massive undertaking requiring a series of complex dives in bad weather with cold, fast-moving water and poor visibility,” said Todd Manny, deputy dive coordinator for the Portland District of U.S. Army Corps of Engineers. “But it had to be done as divers and the dive team needed to know about structural dangers and the possible existence of unexploded ordinance below the underwater mud line.”
The last two trips included destructive testing of timber piles using underwater drills and chain saws. “We cut samples out of Pier 2, which had been closed based on our routine inspection findings. The timber and the conditions are the same, it’s in the same water, and it’s subjected to the same environment, built at the same time with the same materials,” said Hudacek. “These tests help us to determine the actual bending and compressive strength remaining in the timber, how much creosote preservative is left in the piles, and if any fungal decay or marine borer damage [see inset below] is present.” Engineers are using the detailed inspection results to complete a more accurate structural load analysis and develop a 3-D model for Pier 3, which houses a maritime crane for lifting containers.
“The over-arching goal of the program is to find and correct deficiencies before there is failure,” said Kevin Haskins, Army Corps project manager for the pier inspections. “Our work at MOTCO is an example where going the extra mile and taking an extra step programmatically was, inherently, a good thing.”
The Army is in the process of designing a multi-million dollar replacement for Pier 2, but the project is not scheduled for completion until 2019. Until then, KCI’s inspection results can help determine any needed repairs to maintain current operation levels of this mission critical ship loading facility.