Across different structural forms, steel bridges comprise recurring elements. Understanding their function helps interpret drawings and specifications without implying design responsibility.

Superstructure: elements above the bearings (deck, main girders/boxes, bracing).

Substructure: abutments, piers and foundations transmitting loads to ground.

Traffic‑carrying surface. May be concrete, steel plate/fabricated deck, or composite steel–concrete. In tied‑arch or cable‑supported forms the deck can act structurally as a tie or compression element.

Primary members supporting the deck and transferring loads to supports. Rolled “beams” tend to serve shorter spans; fabricated “girders” address higher capacity or bespoke geometry. Connection and stiffening details influence performance and inspection access.

Articulation typically comprises fixed, guided and free positions to manage rotations and movements.

Pot bearings are common for short/medium spans; elastomeric pads for small spans/footbridges; fabricated bearings for uplift/specific rotations.

Taper plates can level bearings on longitudinal gradients; details must be provided early to the fabricator.

Jacking provisions for future bearing replacement are a prudent inclusion.

Construction vs in‑service needs differ: supports and hogging regions often require bracing; mid‑span plan bracing is typically avoided during concreting if flange sizing controls stability.

Ladder decks rely on cross‑girder stiffness for restraint; knee‑bracing only where required.

Curved decks and substandard headroom may require additional lateral restraint to bottom flanges.

Bearing/jacking stiffeners are “fitted” to the loaded flange; intermediate stiffeners generally are not in bearing.

Cope‑holes vs snipes: for weathering steel, cope‑holes aid drainage; for painted systems, close snipes can simplify coating.

Avoid unnecessary full‑penetration welds in non‑critical locations to reduce distortion and cost; allow access for bolting and coating.

Expect different accuracy regimes: precision components (bearings/plates) vs concrete tolerances; details must allow for adjustability.

Execution tolerances follow BS EN 1090‑2: essential vs functional tolerances; project specifications should avoid over‑tightening requirements.