Bridge

A multitude of identifiable bridges exist, including the “beam bridge” which “consists of a horizontal beam supported at each end by piers,” the “truss bridge” which “consists of an assembly of triangles” that are “commonly made from a series of straight, steel bars” [1]. Other bridges include the “arch bridge,” with its “great natural strength,” characteristic arches within the bridge, and “steel or concrete” components and the “suspension bridge” which can “span 2,000 to 7,000 feet” which is “farther than any other type of bridge” and includes a “truss system beneath the roadway” [1]. The last major type of bridge is the “cable-stayed bridge” where “cables are connected from the pylons to the deck below” and where “connected at different points of the column this creates a fan like pattern” [2].

Arch bridges are commonly made with “masonry stone, concrete, timber, wrought iron, cast iron and structural steel.” Truss bridges commonly use “timber, iron, steel, reinforced concrete and prestressed concrete,” and cantilever bridges with “structural steel, iron, and prestressed concrete." The most recognizable type of bridges are suspension bridges, which “utilize spreading ropes or cables from the vertical suspenders” that are made of “steel wire." Cable-Stayed Bridges are another type of bridge, which uses “deck cables that are directly connected to one or more vertical columns,” with “common build materials” of “steel or concrete pylons” [3].

Bridges, themselves, contain a variety of structural components. These include the broader “foundation (which holds the shallow or deep base of the bridge and transfer its load to the bearing strata,” the “substructure (piers, abutments, spandrels and more that holds the upper construction)” and the “superstructure (parts of the bridge mounted on top including decking, girders, slabs)” [4]. Bridge parts that are particularly recognizable include “piles” which “serve as the leg or support for the bridge,” bridge “arches” spandrels, which are the “almost triangular space between the main pillar of the bridge and decking” [4]. More features include the “trusses,” which are a “framework made by connecting triangles and other forms that share load and stress forces across the entire structure” [4]. “Girders and abutments,” which respectively run under the bridge deck, supporting the deck and sit at the ends of a bridge span and support the substructure [5].

Specific types of bridges include “pedestrian bridges” which are primarily “pedestrian-only,” “double-decked bridges,” “train bridges,” as well as “pipeline bridges” which “carry pipelines across water,” and “commercial bridges” where buildings such as “restaurants are located on top” [3].

References

[1] PBS Online. (2000-2001). Bridge Basics. Retrieved (2021, August 3), from https://www.pbs.org/wgbh/buildingbig/bridge/basics.html

[2] Engineering Clicks. (2019, September 4). Types of Bridges. The 7 Main Types. Retrieved (2021, August 3), from https://www.engineeringclicks.com/types-of-bridges/#:~:text=There%20are%207%20main%20types,the%20structure%20of%20different%20bridges

[3] History of Bridges. (2021). Types of Bridges. Retrieved (2021, August 3), from http://www.historyofbridges.com/facts-about-bridges/types-of-bridges/

[4] History of Bridges. (2021). Structure, Components and Parts of Bridge. Retrieved (2021, August 3), from http://www.historyofbridges.com/facts-about-bridges/bridge-parts/

[5] Willamette River Bridge Advisory Council (WRBAC). (2010, November 10). Willamette River Transit Bridge WRBAC Meeting #1. Retrieved (2021, August 3), from https://trimet.org/pdfs/pm/general_docs/RosalesPartners_July15_Slides_62-96.pdf