A Case Study on Two-Span Post-Tensioned Concrete Bridge Decks with Different Span Lengths and Investigation on Prestressing Tendons with Comparisons

Post-Tensioned (PT) concrete system is one of the widely used bridge superstructure types because of its better load capacity performance. By increasing load carrying capacities on conventional reinforced concrete structures, PT is considered as an advanced technology in engineering. The aim of this paper is to study on finite element analysis of two-span PT concrete bridge decks with different span lengths. For three different span lengths, two-span bridge decks were investigated. To reduce the self-weight of the deck, at mid spans, deck section was used as voided section and at diaphragm regions, section was used as filled. Twodimensional Finite Element (FE) deck models were created by frame elements. The FE software package Midas Civil was used. Permanent, transient and time-dependent loading types were considered. Boundary conditions were defined with their real mechanical properties. To balance the deck section stresses, prestressing tendons were used. By iterations, PT tendons layout and types were studied. Interaction between span lengths and PT tendons areas was investigated. Also, different effects on PT tendons were studied and relevant comparisons were submitted. The “best” tendon using was examined for the investigated deck sections. Concluded that optimization on PT tendon areas at bridge deck sections is possible by investigating the main effects on it. Results show that a good optimization enables us to have the optimal PT tendon using with lower cost.Keywords: bridge, deck, post-tensioned, tendon-optimization

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