When existing multiple simple span bridges are converted into a continuous span in order to increase the load carrying capacity by connecting each opposite ends of the simple beams, the rigid support conditions (pin and roller supports) have to be changed to elastic supports in order to absorb and distribute the energy of large horizontal motion due to earthquake loading. However, it may overlook the development of additional stress in the transverse direction of the slab due to the relative vertical displacement of the elastic support. In this study, a simple span bridge specimen of 1/6 scale is tested and analyzed by the use of F.E.M. to investigate strain increase in the transverse direction of the slab when the rigid supports are replaced by the elastic supports. Both test and analytical results exhibit a notable increase of transverse stress throughout the whole feasible range of the vertical support stiffness.