How do field-erected bolted connections differ from shop-assembled bolted connections?

• A. Field connections are preassembled to tight tolerances.
• B. Field connections are welded on site.
• C. Field-erected connections are assembled on site and may require shims and on-site tensioning; shop connections are preassembled to tighter tolerances.
• D. There is no difference.

Answer: (C)

Field-erected bolted connections are assembled on the construction site, where exact hole alignment and member fit can be affected by erection tolerances and field conditions. Because of that, crews may need shims to fill gaps and on-site tensioning to achieve the required bolt pretension and proper alignment. Shop-assembled connections, in contrast, are fabricated and preassembled in the controlled shop environment, with tighter tolerances and bolts tightened to the specified pretension before shipment. This contrast—on-site assembly with potential shims and on-site tensioning versus factory preassembly with tighter tolerances—is why the described difference is the right one.