الفهرس 
POST TENSIONED REINFORCED CONCRETEOnly 14 pages are availabe for public view
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Abstract
Reinforced Concrete Box Girders (RCBGs) are important elements in concrete bridge structures, which resist loads acting on the carriage road. A box girder bridge comprises from girders in the shape of a hollow box. The main objective of this research is to study the behavior of post-tensioned RCBGs strengthened with different composite materials on their flexural behavior under static and cyclic loads. The current work presents experimental work to construct and test ten RCBGs of dimensions 350x350x2500 mm.
The girders were tested under flexure using two points loading up to failure. group 1 contains five box girders tested under two point static loads up to failure. group 2 contains five box girders tested under two point cyclic loads. The first cycle load was about 75% from failure static load and the load increases in each cycle by 10% up to failure. Two girders in each group were tested as control girders. One of the control girders was tested without post-tensioned wires and the other was tested using two post-tensioned wires with a diameter of 12.7 mm and both of them without using any strengthening materials. The remaining three girders in each group were strengthened with welded wire meshes, Geo-grid meshes and GFRP sheets.
The structural behavior of tested specimens in terms of load-deflection curves, ultimate loads, cracking behavior, concrete strain, steel strain and energy absorption were presented and discussed. Experimental results are then compared to analytical models using (ABAQUS) program. The main conclusion was that the post -tensioned RCBGs strengthened by three layers of GFRP achieves the highest structural performance compared with the other strengthened box girders. The FEM simulations have achieved better results in comparison with Exp. results.