Two buildings move differently. Wind sway, thermal expansion and settlement of each building. One end is usually fixed, the other on sliding bearings with a movement joint.
Camber. Pre-camber is built in so the deck is level under dead load, and checked at trial assembly.
Lifting. Crane position and piece weight set splice locations and temporary supports. The lifting plan is part of the scheme.
Coating. Outdoor exposure, often ISO 12944 C4, with a durable top coat for appearance.