ECONOMIC REVIEW OF VARIATION OF PRESTRESSED GIRDER LENGTH ON BRIDGE CONSTRUCTION PRACTICES

Abstract

In the last decade, long-span continuous beam bridges have been built to meet the need of the totalbridge length requirements for obstacle avoidance. In almost 100 years of development of bridge construction coupled with the development of concrete technology, the maximum bridge length, which was originally about 20 m, currently has reached a length of 50 m or longer with the use of prestressed construction. The longer girder length will reduce the number of pillars, minimize the possibility of damage to the pillars due to local scouring or expand the coverage of the free area under the bridge. This study aimed to evaluate the economical aspect of the use of prestressed girders with length variations of 40 m, 50 m, and 60 m. The analytical calculations were carried out based on the applicable standards of bridge design. The results of the study indicated that the most economical configuration for a long span bridge (200m-400m) is the use of a prestressed girder length of 50 m with a girder cross-section height of 2.10 m. However for 480m bridge lengths, 60m PCI girder lengths tend to start out lower. It can be concluded that for a longer bridge span, a longer PCI girder is also required.