Structural Terms

Abutment – Supporting structure that holds up or provides foundation for the bridge.

Bridge Inspection Cycle – NJDOT performs regular and emergency structure inspections in compliance with the federally mandated National Bridge Inspection Standards. Regular inspections for a singular structure occur every two years, with each new iteration of the inspection resulting in a new cycle of the Bridge Evaluation Report. Based on the results of these inspections and reports, NJDOT develops projects and programs for structural asset preservation.

Deck – The Deck is the surface of the bridge that vehicles ride on. It may or may not be covered with a wear surface such as asphalt. The bridge deck is often steel-reinforced concrete and is supported by the Superstructure.

Efflorescence – The migration of salt to the surface of a porous material, where it forms a coating.

Functionally Obsolete – A functionally obsolete bridge is one that was built to standards that are not used today. These bridges are not automatically rated as structurally deficient, nor are they inherently unsafe. Functionally obsolete bridges are those that do not have adequate lane widths, shoulder widths, or vertical clearances to serve current traffic demand, or those that may be occasionally flooded.

Pier – A pier is an intermediate support for the adjacent ends of two bridge spans.

Scour – The removal of sediment such as sand and gravel from around bridge abutments or piers. Scour, caused by swiftly moving water, can scoop out scour holes, compromising the integrity of a structure.

Simply Supported –  A bridge made up of only two beams spanning between two supports.

Spalling – Deterioration of a concrete structural component occurring at the surface where concrete decomposes, often leaving steel reinforcement visible and open to additional corrosion.

Span – The structure that rests on the supports of a structure or the distance between two supports holding up a structure.

Structurally Deficient – Bridges are considered structurally deficient if they have been restricted to light vehicles, closed to traffic or require rehabilitation. Structurally deficient means there are elements of the bridge that need to be monitored and/or repaired. The fact that a bridge is structurally deficient” does not imply that it is likely to collapse or that it is unsafe. It simply means the bridge must be monitored, inspected and maintained.

Substructure – The bridge substructure is essentially the bridge’s foundation supporting the superstructure. This includes abutments and piers.

Superstructure – The bridge superstructure includes the structural elements that support the bridge deck. These may include steel beams, a concrete frame or culvert, steel cables and a floorbeam system as used in a suspension bridge, or a steel truss.