Verification of experimental tests on roller bearings by means of numerical simulations

Roller bearings are an important part of a new construction procedure for large concrete bridges which has been developed at Vienna University of Technology. This new method will considerably speed up construction without relying on erection girders. In the "balanced lift method'' the proposal is made to build the bridge girders in vertical position and to rotate the bridge girders into the final horizontal position. The bridge girders can be built in combination with the pier using self climbing formworks which will allow for lower production costs and shorter construction time. Two different versions of this construction method can be applied, either construction with compression struts or construction with tension ties. An innovative feature of the new bridge construction method is the design of the joints, where large rotations have to be accommodated. Curved steel plates serve as formwork for the bridge girders or the compression struts along the contact surfaces. In case of the tension tie bridge, the hinges are the ends of the bridge girders, whereas for the compression strut bridge they are the ends of the compression struts. Therefore, a preliminary test on roller bearings was carried out in July 2008. The hinges had a radius of 2 m, a steel thickness of 10 mm and a concrete strength of 42 N/mm(2). Further tests were carried out in July 2009 in which the parameters radius (R = 0.5 m, 1.0 m, 2.0 m), steel plate thickness (t = 10 mm, 30 mm) and quality of concrete (C20/25, C50/60) were varied. The test series with a total of 20 hinges was accompanied by numerical simulations using nonlinear finite element programs. In the nonlinear analyses the nonlinear material behaviour as well as the contact problem at the line of contact between two hinges has to be taken into account.