Nowadays the most modern and economical bridges are designed as composite structures with orthotropic plates. In a traditionally designed composite bridge the trapezoidal, longitudinal stiffener is attached, welded to the cross girder web and to the bottom flange of the main girder. However in recent composite bridges with orthotropic plates designed by the UVATERV Co. the cross girder web and the trapezoidal, longitudinal stiffeners are not connected. This is a very important improvement, since in this way the amount of cutting and welding work can be reduced, however more importantly there is no need to consider the fatigue of the welds between the longitudinal stiffener and the cross girder web. On the other hand the disadvantage of this design that the plate-buckling phenomenon of the free edge must be taken into account. This paper studies the new orthotropic plate by the experimental tests.