1 research outputs found
Increasing the Capacity of Existing Bridges by Using Unbonded Prestressing Technology: A Case Study
External posttensioning or unbonded prestressing was found to be a powerful tool for retrofitting and for increasing the life
extension of existing structures. Since the 1950s, this technique of reinforcement was applied with success to bridge structures
in many countries, and was found to provide an efficient and economic solution for a wide range of bridge types and conditions.
Unbonded prestressing is defined as a system in which the post-tensioning tendons or bars are located outside the concrete crosssection
and the prestressing forces are transmitted to the girder through the end anchorages, deviators, or saddles. In response to
the demand for a faster and more efficient transportation system, there was a steady increase in the weight and volume of traffic
throughout the world. Besides increases in legal vehicle loads, the overloading of vehicles is a common problem and it must also
be considered when designing or assessing bridges. As a result, many bridges are now required to carry loads significantly greater
than their original design loads; and their deck results still deteriorated by cracking of concrete, corrosion of rebars, snapping of
tendons, and so forth. In the following, a case study about a railway bridge retrofitted by external posttensioning technique will be
illustrated