Project Tag: DSV Munson (Seattle)

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.

Boat Explosion Response

Global mobilized a rapid response team to the Jim Clark Marina Explosion after one of the resident boats blew up in the early hours of August 24th,2010. The exploding boat caused the complete destruction of it’s boat house and damaged three other boat houses including catching an adjoining boat and boat house on fire. Our crew’s initial response consisted of surveying the damage and deploying boom to prevent any debris or contamination from leaving the accident site. Global’s Dive Operations Mgr says “We were chosen as a full service emergency response provider due to our conveniently poised response equipment,our knowledgeable personnel,and our prior work experiences.”

Hiram M. Chittenden Locks – Emergency Scour Inspection

A recent inspection dive performed by US Army Divers identified a large area of scour on the outer wall,Global installed permanent points on the wall to base measurements. Reference points will enable future measurements to be made identifying additional scour. A hand held sonar was also used to create a visual image of the scour.

Angel Rae Salvage

A live-aboard vessel sank at it moorage on the Duwamish River. Global Diving was contracted by Department of Ecology to mitigate any potential fuel release as well as raise the vessel and remove it from the water. Containment boom was deployed around the vessel as well as various locations around marina to mitigate the spread of fuel in the river current. The fuel vents and caps were sealed. Lifting straps were run under the vessel. A derrick was brought to the site to lift the vessel off bottom. Once on the surface,water was pumped from the hull.

Hood Canal Bridge Replacement

We were contracted by Kiewit to provide diving and ROV services to route the 3-inch galvanized steel anchor wires through the new concrete anchor blocks that support the new east half of the bridge. The anchors are located in 60 to 380 feet of water. The new anchor wire was pulled through an anchor and connected to the bridge where the proper tension was achieved. Each leg of the two wires that attach to the anchor block has a tensile strength of over 1 million pounds. The anchors themselves weigh over 2 million pounds each. The project required the placement and connection of 20 anchors to secure the bridge in place.

Our divers connected the new anchor lines to the messenger lines that were in place and observed that the new wire,as it was pulled through,did not kink or get bound up. On the deeper anchors,the Cougar XT ROV was used. This vehicle,equipped with two five-function manipulators,was able to make the required connections and had enough power to stay on station during all but the heaviest currents.