1. Parts Department

Burns, shears, punches, drills, and bends small plate and shape material that is welded and bolted into larger bridge components and assemblies such as bearings, cross frames, stringers, girders, box girders, tub girders, truss members, and arch components.

2. Material Prep

Flange plates are burnt to width from a plate using the CNC burning / layout machines in the Material Prep area.

3. Web and Flange Splicing

Flanges that are to be spliced have bevels cut at the ends, then are welded together at the bevels. Each welded splice is then non-destructive tested by Quality Control to insure weld soundness using applicable codes.

Web plates are spliced, welds are tested, then web is placed on CNC burning/layout machine to be cut to width and length. Stiffener locations are laid out and field splice holes are laid out (if required).

4. Girder Build-Up

Flanges are tightly fit to the web (first bottom, then top), and secured. The flanges are then tack welded to the web.

5. Squirt Welding (Web to Flange)

Welds are applied to the bottom and top flanges using squirt mobiles to transport the flux/wire welding guns. After the bottom web to flange is welded from both sides simultaneously, an overhead crane picks the girder and rolls it 180 degrees to allow welds to be applied to the top web to flange weld location.

6. Fit-up

At this stage, the stiffeners are fit to the web and tacked into position. A Dart welding machine straddles the girder and welds both sides of the stiffener to the web. When the first side of the girder is complete, the overhead cranes roll the girder to the other side and the fitting and welding process is repeated. At this point, field splice holes are drilled.

7. Finishing

The girder is picked up and placed on stands in a vertical position for welders to weld the stiffeners to the flange. If the girder is curved, both flanges are checked for sweep. The girder is then rolled on to its side; flange ends are burned to match the length of the web; holes are drilled in flanges for splice plate connections; and a final camber check is done. The girder is then rolled and stood bottom down.

8. Setup and Ream Assembly

The girder is moved outside, where it is set to on-site elevations and lengths. This guarantees correct fit. Some assemblies also require reamed cross-frames/diaphragms.

9. Blast Cleaning

The girder is moved inside to the paint bay, where it is run through a blasting machine to remove mill scale, rust, and grease prior to painting. For weathering steel girders, this is the last step before storage in the yard and shipment to the job site.

10. Painting

Girders that require paint are then moved to the paint area, where they receive the required coatings. A typical three-coat paint system requires a prime coat of inorganic zinc, and intermediate coat of epoxy, and a finish coat of urethane in the desired color. Girders are then carefully transported to the yard for storage to await shipping.