Full-Range Modeling of Underdeck Cable-Stayed Bridges

Abstract

Underdeck cable-stayed bridges have recently been shown as one of the promising bridge types due to their multiple advantages such as high structural efficiency, elegant appearance, and economy. The stay cables located under the deck not only introduce axial compression to the deck but also provide additional support to it. Both the ductility and ultimate load should be carefully examined in the design, which requires the estimation of full-range behavior. To predict the full-range behavior considering the material and geometric nonlinearity of underdeck cable-stayed bridges with prestressed concrete decks, an analytical beam model and its corresponding beam finite-element model are developed. The model adopts the actual stress–strain relationships of materials and can take into account the interaction between the flexural and axial deformations of the deck. In the structural system, the interaction between the stay cables and the deck is taken into account employing nonlinear kinematical theory. The analytical model is verified against experimental results. Numerical examples are given not only for illustration but also for investigation of various parameters governing the ultimate load and ductility.