It has also told its employees that it is preparing to sell its renewables division, including a second site in Chepstow that manufactures towers for wind turbines.
A consultation process will now be carried out with all staff affected.
The Chepstow infrastructure facility has an annual capacity of 30,000t and is dedicated to plated and other heavy steelwork fabrication and protective treatment. It can produce components up to 50m long and weighing up to 100t.
Recent bridge fabrication projects have included the River Taff Central Link Bridge in Merthyr Tydfil.
“Like many companies we are forced to consider every possible option to remain competitive in difficult times,” said the company’s statement. “The proposal follows a comprehensive review of the Mabey Bridge business. We are confident that these proposed changes will help build a stronger, more sustainable future for Mabey Bridge’s modular bridge business in Lydney.”
The Lydney facility in Gloucestershire, England, is dedicated to the manufacture of the company’s modular steel bridge systems and has an annual capacity of 35,000t.