Work will start later this month to replace four solid steel “A-frames” which connect the main span bridge deck to the towers at either end of the crossing.
The works will require the closure of the nearside lane in both directions for up to 40 weeks.
The A-frames each weigh five tonnes and are below the 1,410-metre main span of the bridge.
The bearings, which allow them to move as the bridge contracts and expands with the weather, have become worn over time.
It is Spencer’s third major win on the Humber Bridge after contracts to project manage an inspection of the suspension cables in 2009 and main cable dehumidification work in 2010.
Spencer’s team of subcontractors on the latest complex project includes ESL of Hull, which is carrying out the strip-out works; scaffolders Harsco, of Immingham; electrical contractors Pennine Control Systems, of Huddersfield; and steel fabricators Allerton Steel, of Northallerton.
Spencer Group Project Director Jim Mawson said: “This is another example of us taking on a complex and challenging job that other companies would perceive to be risky.
“We’ve got the people, the experience and the capability within the business to be quite comfortable with it.
“We’re accepting risk based on the fact that we have the team and the expertise to support this contract and meet and, indeed, exceed the client’s requirements.”
At its peak up to 30 Spencer workers and subcontractors will be on the project.