Nonlinear Behaviour of Under-Deck Cable-Stayed Bridges with Steel−Concrete Composite Decks

<p>The effect of geometric nonlinearities in the response of under-deck cable-stayed bridges with steel−concrete composite decks is studied. Influence lines for deflections and bending moments at different sections of the deck are obtained, and these are found to be different to those for conventional bridges. Nonlinearities affect principally the response of lateral subspans, in which both deflections and bending moments are amplified. The permanent state should be studied by taking nonlinearities into account. Deflections under further loads can be obtained with linear models. Geometric nonlinear effects increase design bending moments under ultimate loads by 12% when compared with linear models. Some additional design criteria for designers aiming to design under-deck cable-stayed bridges are hence provided.</p>