Basic differences between bridges and culverts

Bridges and culverts are inherent segment of the infrastructure of our society. The purpose of them is to arrange passage for transportation, generally over flowing water. But they are differentiated with several factors like length, purpose, the complexity of design, building components, and structure.

Bridge - A bridge stands for a structure that allows a transmission route to convey a roadway or railway traffic over a physical obstruction including or excluding of water. The transmission route ranges from railway, roadway, cycle track, footpath or an amalgamation of both of them and the obstruction may come in shape of a river, stream, valley, channel, railway track etc.

Generally, a bridge is categorized as follow:-

Minor Bridge: - It is the bridges that has an extent of more than 6m & lower than 60m.

Major Bridge: - It is the bridge with total extent in excess of 60m & lowers than 120m.

Long Span Bridge: - Major Bridge with the primary extent in excess of 120m.

A culvert stands for a tunnel structure or small bridge with complete length of 6m or under 6m among the faces of abutments. The purpose of the culvert is to facilitate running water to bypass under a roadway or railway. Culvert is also effective for water drainage or lapping the space over a physical obstruction.

Given below, some basic differences among bridge and culvert:-

  • A bridge refers to a path of transportation (for people or vehicles) across a massive body of water or physical obstruction but a culvert usually belongs to a tunnel-like structure that facilitates the water to bypass under a roadway or railway.
  • The major elements of a bridge are superstructure (supports load), substructure (delivers load to foundation soil) and deck (delivers surface load to other components) , where the constituents of a culvert are relatively simpler and comprises of concrete boxes or cells (single or multiple), pipes, a top deck or slab and supporting parts.
  • Bridges are developed at a height in excess of 20 feet but Culverts are developed at lower than 20 feet high over the obstruction.
  • Bridge extents from 6 meters (minor bridges) to over 120 meters but the length of culverts is generally not in excess of 6 meters.
  • Piers and abutments belong to the supporting structures of a bridge, where Culverts are generally implanted in the soil that carries the major section of the culvert load.

  • There is no floor in a bridge but a culvert stands for an encompassing structure that includes two sides, a roof, and a floor.
  • The construction of a robust and deep foundation is very crucial in constructing a bridge. The foundation alongside the complete breadth supports the bridge, where no deep foundation is essential for a culvert.
  • A bridge is generally a linear and straight passage but Culverts are entirely surrounded structures that may come in different shapes like semi-circular, rectangular, elliptical or pear.
  • The structure and design of a bridge are complex and so, huge budge is required for its construction, where a culvert can be developed in a low budget.
  • Bridges are generally developed at the construction site or pre-constructed in minor parts but Culverts are pre-constructed or developed at the construction site (in situ culverts).

  • To build up the bridges, there should be requirement of huge time and manpower, where the culverts are simpler to structure and design, so it is built up with not as much of time and labor.
  • Bridges offer a simpler route of transportation that saves time and lessens distance but Culverts can resist water logging, flood, and corrosion, and facilitates water to stream its natural course under a roadway or railway.
  • A bridge is constructed across a body of water that is big and contains inconsistent flow but a culvert is built up when water requires to be bypassed through tunnels or channels under a roadway.
  • Bridges can resist heavy and speeding vehicles but some culverts, like box culverts, contain sharp corners which are not suitable for high-velocity vehicles.
  • The only way of carrying is over the deck of the bridge, where a culvert is built up to adapt roadways both over and under the deck (e.g. a culvert is constructed over another road or railway).

Bridges and Culverts Difference