engleski

Strengthening of Existing Road Bridges with External Post-Tensioning

Assessment and rehabilitation of existing bridges, and concrete structures in general, has become an important issue for civil engineers nowadays. There are several factors causing structural deterioration of bridges. Along with aggressive environment and ageing of material, bridges are exposed to increasing traffic loads, due to rapid growth in volume and weight of heavy vehicles. Furthermore, more than fifty percent of bridges in the region are more than forty years old and designed with previous design standards, which increases the need for strengthening. Among the various methods for increasing capacity of existing bridges available today, external post- tensioning provides very efficient solutions for small and medium span bridges, because of the speed of construction and minimal disruption to traffic flow. Scope of this paper is to give an insight on external PT technique and its application in retrofitting and strengthening of existing bridges. Case studies of assessment and repairing of two bridges in the region using external PT will be presented. There are several design, detailing, durability and construction issues that need to be considered with special care when designing an external PT system. Anchorage zones and deviators should be carefully designed and detailed to ensure transfer of forces to concrete. Furthermore, effects of the new forces introduced to the system must be carefully evaluated, as they depend on condition of existing bridge.

external post-tensioning ; existing bridges ; strengthening ; traffic assessment ; deviators

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