On Seattle’s I-5, the highway sign bridge at Seneca Street needed replacement. Washington State’s highway infrastructure department contracted with a local welding company to remove and re-install the 70-foot lattice sign bridge. 

Without a crane for the heavy lift aspects of the project, the welding company needed an expert crane team that could deliver safe, efficient services. Naturally, they tapped Omega Morgan’s Seattle crane services crew for the project. With numerous hurdles to overcome before execution, our heavy lift team quickly got to work developing a plan.

ELEVATED CRANE SERVICES PLANNING

Working with both the welding company—our customer—and the electrical company providing support for the project, we began planning our timeline,logistics, and how we would travel to the location. 

After they determined the project would be best suited to our Manitowoc NBT60 truck crane, our crew now had a hurdle to overcome. The crane’s total weight is 86,000 pounds, and during the maximum expected lift, the crane would deliver 30,000 pounds of pressure at the outrigger pad over one outrigger. Setting this much weight on an elevated structure over express lanes of 1-5 required approval from multiple parties. 

First, our crane team consulted with Omega Morgan’s engineering crew to confirm our estimate of the crane matting needed to disperse the outrigger pressure to an acceptable level. Then, with their stamp of approval, we submitted the plans to our customer, who signed off before sending them to the Washington State Department of Transportation. After receiving their approval, the plans were brought to the original engineering firm out of California who designed the structure in 1967. Finally, with the plan stamped by all necessary parties, the crew was ready for action.

CRANE LIFT OF 70-FOOT SIGN BRIDGE

In early February, Omega Morgan’s team of two—our crane operator and rigger—met the rest of the project execution team, including welders and electricians, with our crane. The team met in South Seattle before traveling together into the road closure area around 9 p.m. We then set the crane on the elevated lanes of 1-5 and got to work. 

As the team began the removal of the sign bridge, it became apparent that the removal path would bring the load within eight feet of the active northbound express lanes, with traffic traveling in excess of 60 miles per hour. Putting safety first, our crew maneuvered the component through the tight spot with precision and care. Once past that challenge, the rest of the replacement continued smoothly.

Over 10 hours, the crews worked together to finish replacing the lattice sign bridge structure measuring 70 feet long and eight feet tall. Finally, around 7 a.m., with work complete, our team loaded up the truck crane and returned to the yard after a successful heavy lift.

Our customer appreciated the safe experience and reliable heavy lift support. In addition, they were very happy with our ability to work together with multiple teams towards a common goal.