الفهرس 
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Abstract
Externally prestressed concrete deck bridges with cables deviated under the deck are one of the suitable systems for medium spans range (from 50m to 80m); using this structural system for medium spans range has several economic and aesthetic advantages compared to traditional solutions. Increasing structural efficiency of the structure by reducing the flexural demand on the deck and enhancing the axial response, increasing the deck slenderness, reducing the vertical and seismic loads on piers and foundations, efficient use of materials resulting in more economical and sustainable construction, improving the aesthetic consideration of the bridge. However, this structural system is uncommon, and only a limited number of these bridges have been constructed worldwide, probably due to the requirements for vertical clearance below the deck and the limited knowledge about this structural system. In order to contribute towards filling this gap, a parametric study has been performed for simply supported and continuous spans with externally prestressed concrete deck bridges with cables deviated under the deck for a span of 50m and 80m. The parametric study gives a detailed picture of the distribution ratio of vertical live loads between deck and cables for different span-to-depth ratios. In addition, the range of stress change in cables due to frequent live loads to determine the allowable stress of cables for different span-to-depth ratios. Also, this study provides the designers with some guidance on a preliminary estimate of the required material quantities for the bridge superstructure (deck) for different span-to-depth ratios for the calculations of cost pre-estimates during the feasibility studies of similar bridge conditions and dimensions. Also, this study evaluates the economic impact of simply supported and continuous spans with externally prestressed concrete deck bridges with cables deviated under the deck compared to internally prestressed concrete deck bridges and externally prestressed concrete deck bridges with cables deviated inside the bridge deck
Keywords: Externally prestressed concrete deck bridges; Under deck cable-stayed bridges; Cable-supported bridges; Bridges supported from below; Nonlinear finite element analysis.