Project Tag: Engineering & Technology

Caisson Cut Off Project

This June, Global completed a complex caisson cut-off job in our California region. With a dedicated four-person team, they were tasked with diving over 40′ below the riverbed, where they meticulously burned through a 60-inch caisson, preparing it for removal. To read more about the job, follow this link: Caisson Cut Off (

Texas Intake Installation Update

Global Diving Continues Work on a Major Marine Construction Project in Texas. The intake will supply drinking water to local municipalities. Intakes are typically installed in the deepest part of the lake. Due to the nature of this, the structure needs to be able to withstand intense water pressure and environmental conditions to ensure the …

Anode Installation for Juneau, Alaska Cruise Ship Terminals

As the cruise service between the Pacific Northwest and Alaska increases so does the need for additional berthing and dock space. To accommodate this growth,Manson Construction was awarded the contract to fabricate and install two new cruise ship terminals in Juneau,Alaska.

The terminals are comprised of 2,331 new steel pilings,after being driven into place each requiring a sacrificial anode welded to the piling. Global was subcontracted to perform this challenging and critical aspect of the project. The anodes,ranging in weight from 216 to 260 pounds,had to be installed in accordance with AWS D3.6 welding standards at various depths,up to 105 feet below the water line.

Global personnel worked hand in hand with Manson’s project staff to minimize the impact on the project schedule. The crew successfully installed all anodes on a complex array of piles,in adverse conditions,without injury while maintaining the tight schedule set by the client.

Seattle T-46 Barge Refloat & Fender Piling Repair Project

Seattle’s most extensive current civil works project,the Alaskan Way Viaduct replacement tunnel,is being constructed using the world’s largest tunnel boring machine ‘Bertha’. Due to the proximity of the construction site to the waterfront,the dirt and rock spoils from this effort are transported via conveyor belt to Pier 46. From there it is loaded onto barges for further transport.

Progress was recently halted due to an incident involving a spoils barge and a badly damaged pier.

In the early morning hours,the barge being utilized began to list and then capsize. Tunneling operations were halted due to the partially capsized barge at the adjacent pier and an impending rising tide.

The tunnel project personnel called Global’s 24 hour number to request immediate assistance. Global dispatched a Salvage Master who was on scene within 30 minutes of the call.

Following the removal of the unstable barge from underneath the pier,Global commenced a full salvage assessment. This included analysis of the barge’s stability and an underwater survey. The spoils had shifted on the barge causing it to list heavily to one side. Global developed a lightering plan and engaged a crane barge with a clamshell bucket to transfer the loose spoils to another barge.

As a precaution,Global positioned high capacity pumping equipment on location. Draft measurements monitored throughout the lightering indicated the presence of an unbalanced load in the barge. During the operations significant damage to the barge was observed. This information was incorporated into the lightering plan to ensure the safety of the operation. Following the lightering procedure,Global removed the damaged bin rails and prepared the barge for transit through the Ballard Locks.

The pier sustained significant damage to the fender piling from the capsizing barge. Global’s team quickly developed and proposed a repair plan. Following approval,Global removed the damaged piling and drove new steel replacements.

Additionally,it was determined a new fender system was required before loading operations could resume. Global’s team designed and installed an approved fender system allowing the project to continue tunneling operations.

Global provided salvage,environmental,and marine construction services to expedite and safely resolve this unexpected incident.

Cornell Lake Source Cooling Intake Cleaning

The project involved anchoring a sectional barge in 250′ of water on an inland lake,and recovering an intake screen weighing over 4 tons to the surface for cleaning and inspection. With the screen off,cleaning pigs (3) were sent through nearly 2 miles of 62″ diameter pipe to clean accumulated quagga and zebra mussels.

There was miscellaneous work at the inshore Heat Exchange Facility building removing and installing large blind flanges to allow the pigging operation to take place. These flanges weighed up to 5700 pounds,with work taking place in a wet well 35′ deep.

Rocky Reach Spillway Apron Underwater Concrete Repair

We were contracted to preform an underwater concrete repair to the spillway baffle under spill gate 3,and preform an inspection of the spill way and dentate from spillway 2-8 and 9-12. the spillway was separated into two sections by a fish ladder between Bays 8 and 9. The perimeter of the eroded areas were delineated using an U/W track creating a key way,ensuring a minimum depth of repair,throughout the area. Divers used rivet busters to remove concrete from the key cut as well as from under exposed rebar to ensure encapsulation and to allow couplers and new rebar to be added in areas wee eroded. Divers then used a 20k hydro blaster to wash away loose material and marine growth. Once the areas were prepared and cleaned,custom form tops were installed. The forms were made to fit the round side of the baffle that was approx. 18’x20′ and was rock anchored in place. Eight cubic yards of high strength concrete was then pumped into the form. While the concrete cured in the forms,the inspections were carried out of the stilling basin floor. The forms were removed and the project demobilized.

Rock Island Dam Adult Fishway Extension

Rock Island Dam is located on the Columbia River,approximately 15 miles south of Wenatchee,WA. The development of a crack in a spillway of Wanapum Dam,downstream of Rock Island Dam necessitated a 25 foot drawdown of the tailrace. This created a significant obstacle for the fish migrating upstream; they would not have access to the original fish ladder. With the arrival of the migrating salmon just a few months away,this project took on a critical path very quickly.

Chelan County PUD,owners of Rock Island Dam,contracted Knight Construction from Spokane to install the emergency fish ladder extensions in three areas,two on the west bank and one on the east. Knight,who handled the fabrication and topside support,turned to Global Diving & Salvage,Inc. to provide the diving support for the project. With the compressed schedule required to complete the project,Global and Knight worked closely on scheduling the arrival of the fabricated items and their installation.

The extensions,similar to the structural components of the original fish ladder structure,consisted of steel boxes and flumes used to create pools and steps. These new boxes and flumes were mounted to the face of the dam and in the case of the east side,were suspended from a pipe that spanned two pier noses. The project involved a wide array of construction techniques,including; core drilling,setting of epoxy and mechanical anchors to secure the boxes and frame work in place,wall sawing to remove sections of the dam to allow access at the lower water levels. The steel sections were bolted and in some cases welded in place.

By all accounts the project has been a great success. According to the Wenatchee World,over 20,000 of the expected record 235,000 Chinook salmon migration have already traveled upstream past Rock Island Dam.

ROV Makes Deep Sea Pipe Repairs

Global’s Cougar and Falcon ROV systems were mobilized to Hawaii to facilitate repairs on the 40” coldwater pipeline transition section in 500 feet of water off of Keahole Point on the island of Hawaii for the Natural Energy Laboratory of Hawaii Authority (NELHA).

The 40” pipeline is unique in the fact that it is installed with gravity anchors to a depth of 457 feet and from there to a depth of 2000 feet it takes the form of an inverted floating catenary. An installation error when the pipeline was originally installed in 1987 led to future failures of chain bridals and anchor chains. In addition growth on the pipeline was weighing it down.

The ROV crew,operating off of the Healy Tibbitts 544 crane barge,was tasked with restoring the pipeline to an as designed condition. The Cougar ROV cut loose and replaced two 500 foot 1-1/2” stud link restraining chain bridals. The pipe had to be cleaned and obstructions cut loose for the installation of new pipe clamps in three places. 1-1/2 tons of flotation was added at each clamp location. Two 1-1/2” stud link chain bridals were added at the bottoms of the clamps and secured to a 40 ton gravity anchor. A 1-5/8”stud link chain bridal was added to the offshore bridal. Special underwater tooling was designed and manufactured including a hydraulic chain tensioner,3-1/2 and 10 ton winches and 40 and 48 inch hydraulic actuated pipe clamps that were tested in Seattle before being deployed to Hawaii.

Horse Mesa Dam, Units 1 – 4 Intake Repairs

Global Diving & Salvage,Inc was contracted by Salt River Project (SRP),operator of Horse Mesa Dam,located 65 miles northeast of Phoenix,AZ,to provide project management and diving services to make repairs of Units 1 through 4. The work on Unit 4,located in 160 feet of water,and on Units 1,2,and 3,located in 260 feet,necessitated the use of saturation divers.

Saturation diving is a method where divers live at a pressure equal to the depth they are working and transit to and from the work area via a diving bell. When not working,they live in chambers that are located on the deck of the barge. A crew of 21 working in two 12-hour shifts are required to support both the divers on deck and those in the water. In saturation diving,decompression is not eliminated; it is delayed until their rotation is over,which is usually 30 days. On this project,it took three days to decompress from the working depth to the surface.

In June 2012,a vertical concrete guide vane located in Unit 4 failed. Divers removed the remaining sections of the damaged vane as well as a second still-intact vane,using wire saws and wall saws. A new steel vane system,consisting of two vertical and nine horizontal vanes,was installed in place of the original concrete structures. The vanes were bolted in place and then filled with grout for added stability. New trashracks were installed in the intake. The bulkheads for Units 1,2,and 3 did not seal adequately to the penstock intakes due to deteriorated concrete on the intake opening face. Divers anchored and sealed new steel sealing frames at each intake location. Inspection also discovered deteriorated concrete at various locations in the three sets of gate guide slots on the upstream face,which was repaired.

PLEM Buoy Replacement

A dive team from our California Regional Office was deployed to Okinawa,Japan to assist Truston Technologies,Inc. in constructing as-built drawings of an existing PLEM (Pipeline End Manifold). The buoy and related piping are in 75 feet of water,approximately a half mile offshore from USMC Base Camp Courtney.

Phase I of a scheduled two-phase project involved complicated logistics to deliver a deep air diving system overseas,and to provide subsurface metrology solutions for the construction of a new replacement structure on the sea floor. While on site the existing steel components were carefully documented; ultrasonic thickness readings and corrosion inspection of the existing infrastructure was performed. The crew also inspected the existing Multi-Buoy Mooring (MBM) system; buoys,chains,and anchors.

During the inspections two abandoned ‘ghost’ pipelines were discovered. Topside sonar surveys had failed to detect these abandoned pipelines. It was imperative to the project to fully identify these in order to determine whether their location would interfere with replacement anchors and chain of the refurbished MBM system.

Phase II,scheduled for completion in 2013,will consist of the removal and replacement of the existing PLEM and SBM (Single Bouy Mooring). Information gathered during Phase I was be used for the fabrication and installation of new components.

Divers had to be mindful of the local poisonous marine animals while working underwater. Lion fish and the highly venomous stonefish had settled around the flanges and valves of the existing structure. The divers had to proceed with extreme care during the work,going so far as to remove all rocks on the seafloor in the vicinity of the work area in order to identify camouflaged stonefish.