الفهرس | Only 14 pages are availabe for public view |
Abstract In the last few years cable-stayed bridges have gained a lot of importance, they are widely used for executing medium to large spans of bridges. Due to the increasing of cable-stayed bridges spans, using of slender-decks became necessary. This thesis aims to study the reliability of using an innovative system in the decking of cable-stayed bridges (composite space trusses). from the structural and economical points of view. In this thesis, an analytical investigation is performed to a real bridge (Suez Canal cable-stayed bridge), which its deck is originally designed as a steel box girder type. Two models for the bridge has been performed; firstly as a steel box girder deck and secondly as a composite space truss deck. The two models have been analyzed under several cases of loading, according to the service loads. The composite space truss system has been proved a good and reliable behavior as a decking of cable-stayed bridge. The new system has been recorded stiffness as high as the steel box girder type under the effect of traffic loads. There was not a big difference in the own weights of the two systems especially in the case of using lightweight concrete in the space truss system. But the composite space truss recorded 27% of the consuming steel compared by the box girder type. So the composite space truss system could achieve less cost and construction time than the box girder system. Also new iterative method for calculating post-tensioning forces of cables is introduced and verified. For highly indeterminate structures as the cablestayed bridges, the introduced method could reduce considerablly the computation time of calculating post-tensioning forces of stay cables |