Pacific Maritime Magazine - Marine Business for the Operations Sector

West Coast Maritime Construction

 

June 1, 2020

A tender and his diver finish pre-dive preparations and make final safety and communication checks before the diver enters the water. Photo courtesy of Global Diving.

While much of the world is in forced isolation, the maritime construction industry continues to work on essential projects needed to keep the infrastructure functioning at the interface of land and sea.

In California, American Marine Corporation (AMC) is working on the Everport project at Berths 226 through 236 at the Port of Los Angeles' Evergreen facility, as part of a modernization upgrade.

Working as a subcontractor to Manson Construction, AMC will repair approximately 1,250 linear feet of concrete piles. These underwater repairs are required due to piles that have been cracked, spalled, or broken over time. Due to the severity of damage, pile repairs are classified as structural, non-structural, or broken encasements. Project specifications call for the use of Simpson's FX-70 jacket system for all three types of repairs.

"We begin with a field verification of the pile deficiency to determine the length of repair needed. Jacket lengths are all custom made and they vary in diameter based on the type of repair," explains Stephen Shahnazarian. "If it's a non-structural pile repair, we install the fiberglass jacket form and pour the annulus with marine grade epoxy grout. Structural repairs require a rebar cage and larger diameter jacket, which then gets poured with non-metallic underwater grout. For broken piles we will drill and set rebar into the soffit, install the cage and form, then fill with marine grade epoxy grout." Repair lengths vary from 6 feet to more than 40 feet with an average length of 8-10 feet. The top of the jacket repair will have a bevel finish.

AMC will also assist in the installation of a new sheet pile wall that spans more than 1,700 feet in order to maintain the slope under the dock. Once installed, AMC divers will cut the top of the sheet pile wall with underwater burning gear to provide a level finish. A closure plate will then be welded underwater to tie the new sheet pile wall into the existing structure. Manson will start dredging operations to accommodate larger ships in the future.

"Crews of five to eight personnel will dive in depths up to 50 feet from one of our support vessels. Our equipment utilized for this project includes ChemGrout pumps, pneumatic hammer drills, hydraulic grinders, and underwater burning and welding gear," says Mike Dunn, Dive Operations Manager. "Dealing with vessel traffic and the simultaneous operation of other contractors makes safety paramount." The project is expected to be completed in early 2022.

In Seattle, Global Diving & Salvage, Inc. completed marine construction work at Seattle's Fishermen's Terminal in late 2019.

The under-dock piling of Piers 3, 4 and 5 required pile improvements, including cleaning, wrapping, and installation of a cathodic protection system, in order to increase the life span of the aging facility. Global inspected, cleaned, coated, and wrapped 293 steel piles with Denso SeaShield 2000HD pile protection system. After wrapping the piles, Global installed 1,400 magnesium anodes on the piles to make up the new cathodic protection system. The team also removed miscellaneous waste and debris from the lakebed around the work area.

Global used a 7-person dive team to perform the work, with two divers working in the water simultaneously under the direction of the dive supervisor. A 72-foot barge was outfitted with a Global surface-supplied air dive spread and equipment to serve as a mobile work platform; additional Flexi-floats and a skiff were also used when needed. The team worked around vessel movements and limited moorage space to ensure marine operations on the docks went uninterrupted over the course of the project.

One of the challenges involved obtaining magnesium anodes for installing on steel piles. The Chinese-sourced anodes specified by the Port were delayed and incorrectly sized; Global worked with the Port to modify the anode assemblies so they would attach to the piles and still meet specifications. "To get 1,400 anodes onto the pier, normally doing about 12 to 14 anodes a day, would take you 100 working days, it depends," explains Spencer Smith, Project Manager for Global. To keep the project on schedule, crews started repairing and wrapping the piles at Dock Five. "We started installing anodes when we got to Dock Four. So we did Dock Four and Dock Three and then had to come back to Dock Five to do the anodes on that one."

With many elements of the project occurring concurrently, ensuring safety was critical. Global successfully and safely executed this project without any injuries or incidents. "We had crews working in conjunction with each other, with people welding on the deck to make apparatuses for installing anodes to driving a forklift in a low area out of sight. We pride ourselves in safely managing complex projects," says Smith.

Power Engineering Construction Co. is the builder of the new Seaplane Lagoon Ferry Terminal in Alameda, California. The new ferry terminal is emerging as part of a long-awaited waterfront development on Seaplane Lagoon. The project is part of a $1 billion development by Alameda Point Partners that will bring housing, commercial space, landscaped parks together with the ferry terminal that will deliver passengers to and from downtown San Francisco in just 20 minutes.

The marine portion of the terminal consists of a new concrete pier, a 90-foot long gangway connecting the pier to a boarding float, and a 135-foot long by 42-foot wide steel float designed and outfitted for operations by WETA (Water Emergency Transportation Authority) vessels, also known as San Francisco Bay Ferry.

The crew is headed up by Power Engineering's Project Manager Brian Shalk, who describes a couple of the challenges overcome while building the terminal, which is expected for completion in July 2020.

"One obstacle, during pile driving, was encountering harder sands than expected which led to early refusal for most of our concrete and steel piles," he explains. "The solution was to use real-time pile driving data to re-analyze the actual install conditions of the piles." In addition, "the landside portion of the pier sits on fill that was installed by the Navy more than 80 years ago. In a seismic event, this fill is subject to liquefaction – which would lead to high lateral displacements of the structure. To mitigate this risk, ground improvements were implemented by means of installing forty five 6-foot diameter Deep Soil Mixing (DSM) columns over a 4,000-square foot landing area."

Another challenge, albeit a known one, was the precision required for installation of pre-fabricated components of the project. Due to schedule constraints, a tensioned PTFE (fabric) canopy was fabricated at an off-site location prior to the pier construction. This required the concrete pier to be constructed with extreme precision. This level of detail during the survey, pile driving, and concrete work made for a smooth installation of the architecturally pleasing canopy. Also fabricated at an off-site location was the 200-ton steel mooring float.

Due to environmental regulations in California, the mooring piles had to be installed prior to the steel float. Once the float fabrication was complete, the crew utilized their nautical experience to navigate the barge into position in a matter of minutes. Ferry service is expected to start later this summer.

Associated Underwater Services Inc. (AUS) has been working on a two-year project that started in late 2019. The company has been working on the port of seattle Terminal 5 Project under general contractor Orion.

The dock is being rebuilt and requires underwater welding of approximately 400 anodes that weigh 325 to 725 pounds onto the sheet pile wall. Three to seven-person crews are working on timber, steel and concrete piles and QC inspections. The maximum water depth is up to 70 feet. "One of the challenges is that most of the work that was supposed to be completed in the first year has been pushed to the second year, so we will be having a very busy second year," says Kirk Neumann, AUS' General Manager.

AUS is also working on the City of Seattle Georgetown Outfall Replacement Project in the Duwamish River, working alongside general contractor Pacific Pile and Marine. Three-person crews worked in up to 25 feet of water. The first phase involved the demolition of the old pipe and piles in the area. The second phase included installation of the new HDPE four-foot diameter outfall. "We had to do three underwater flange connections; each had 44 bolts, and the bolts were inch and a half diameter," says Neumann. "Then we had to torque all the bolts to 580-foot/pounds."

The second phase also included survey and placing the backfill. At the end of the project, AUS burned off the sheet pile wall that was used for shoring the construction site.

Last year, AUS completed its work on the three-phased Colman Dock Project for the Washington State Dept. of Transportation and Washington State Ferries. Working under general contractor Hoffman Construction and Pacific Pile and Marine, AUS has performed extensive debris and pile removal and various bottom surveys in up to 50 feet of water.

"There were surveys for debris location and recovery," explains Neumann. "There was a lot of debris on bottom. Once everything was cleaned up, we helped with placing the capping material to prevent any leaking of the creosote from the timber stubs that were left behind."

Working in anywhere from 30 to 70 feet of water, up to four-person crews continued with phase two, helping remove timber, concrete and steel piles. Teams used equipment such as underwater chainsaws, underwater, jackhammers, and underwater burning equipment. "One of the bigger challenges of this project was scheduling and working safely around the ferry traffic," says Newmann. "There was a lot of switching back and forth between day shifts and night shifts, depending on the task and the area that we were working on the dock."

Sub-zero temperatures greeted the AUS team during wintertime work on the Lower Granite Dam Project. The Dam is owned by the US Army Corps of Engineers and is located on the Snake River. The general contractor on the project was Northbank Civil.

"We installed the de-watering structure in 2019 and we removed it in 2020," explains Neumann. The scope of the work was to install and remove a de-watering structure downstream of spillway one and under the Removable Spillway Weir and install fish- reading instruments that were installed in the spillway face. "All of that work was done in the dry by Northbank Civil, but we worked with them to install the de-watering structure," says Neumann.

Diver Hugh Gunn welds a magnesium anode assembly to a freshly cleaned and wrapped steel pile. Divers cleaned and wrapped 293 piles and installed 1,400 magnesium anodes over the course of the project. Photo courtesy of Global Diving.

The maximum depth for five-person crews was 35 feet. "The challenges were working around the water in those temperatures and always able to keep our hot water machine going and all the equipment running," he adds.

Finally, AUS performed the diving for the installation of the de-watering structure at the Cabinet Gorge Dam Fish Passage Facility, which is owned by Avista Utilities.

The general contractor was Slayen Construction. The scope of the work was to build and install a de-watering structure so that the fish facility could be built in the dry. This project involved drilling and installing anchor bolts to secure a series of stanchions. Then the divers installed sheet pile cells connecting the stanchions to complete the structure.

The fish facility is currently under construction, and when it's complete, AUS will be installing the intake structure. This part of the project will be upstream of the Dam and will include installing beams on the face of the Dam, the intake pipe, and the intake screens. When everything is finished, AUS will remove the de-watering structure.

 
 

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