Abstract: Movable bridges are designed and constructed to change its position and occasionally its shapes to permit the passage of vessels and boats in the waterway. This type of bridge is generally cost effective since the utilization of long approaches and high piers are not required. When the waterway is opened to vessels and ships, traffics over the bridge would be stopped and vice-versa. Moveable bridge is a bridge that can change position (and even shape in some cases) to allow for passage of boats below. This has a lower cost of building because it has no high piers and long approaches but its use stops the road traffic when the bridge is open for river traffic. The oldest know movable bridge was built in the 2nd millennium BC in the ancient Egypt.

History also knows for one early movable bridge built in Chaldea in the Middle East in 6th century BC. Since then they were almost forgotten until middle Ages when they again appeared in Europe. Leonardo da Vinci designed and built designed and built bascule bridges in 15th century. He also made designs and built models of swing and retractable bridges. Industrial revolution allowed for new technologies like mass-produced steel and powerful machines and it is no surprise that new types of modern movable bridges appeared in 19th century. They are built even today but many movable bridges that are still in use in United States are built in early 20th century. In time, some of them are repaired with lighter materials and their gears are replaced with hydraulics

Keywords: Traffic, Movable bridges

| DOI: 10.17148/IARJSET.2023.10732