Strengthening of jiamusi pre-stressed concrete highway bridge by using external post-tensioning technology in China

External post-tensioning is defined as a system in which the pre-stressing tendons or bars are located outside the concrete section. The pre-stressing force is transferred to the member section through the end anchorages, deviators or saddles. The objectives of this study are to strengthen Jiamusi pre-stressed concrete highway bridge by using external post-tensioning tendons, to determine the internal forces, and to design the external post-tensioning system. Two software are used in the analysis of the T-shaped cantilever structure and anchor beam. The first is Dr. Bridge software Ver. 3.1, and the second is Ansys software Ver. 10. The results of analysis before and after laying the leveling layer of the bridge deck pavement show that the section of T-shaped cantilever structure can satisfy the demand of vehicle-20 grade and vehicle-50grade grade. The compressive stress of the upper edge of pier top box section is small, it is only 1.91Mpa. Therefore, there is need to strengthen the top of the bridge deck. External post-tensioning tendons are used to strengthen the bridge deck. The selection of external post-tensioning tendons depends on the ASTMA416-90A specification. The external tendons consist of high strength, low relaxation strands, and the standard tensile strength is 1860MPa. The design and construction of external post-tensioning system includes the design and construction of anchor beam which includes the design of re-bars and the design of damper devices, and the layout of external post-tensioning tendons along the bridge deck.