Bridge welders join the metal parts of a bridge. In this role, you weld, braze, and heat cut pieces of metal for both fixed and movable bridges. Some employers may have you fabricate and assemble metal parts to aid in the durability of bridges. For most projects, you work on repairing established structures, though you may also install metal parts on other projects. Depending on the structure, you may need to fix metal roofing or walls through soldering, crimping, or riveting. Most welders work with a company on a contract basis, handling one project at a time until the project is complete.