Regarding indisputable savings in maintenance costs continuous welded rail is installed in almost all track sections which are renewed or newly constructed. A need to solve the interaction between the track and bridge preferably without expansion joints has arisen. A complex evaluation of combined response to variable actions is not required according to the Czech national regulation if the track is renewed and the bridge expansion length is within limits. Exceptions are often allowed for bridges whose expansion length exceeds the limits. Good experience supports an increase of limits but theoretical analysis and structure monitoring are desirable. Five bridge structures – steel, concrete, combined and different deck – with ballast, with timbers or direct fastening, had been monitored for three years in all climate conditions. The displacement of track and bridge was surveyed by precise geodetic methods. The longitudinal reactions in bridge fixed bearings were measured for the bridge. Finite element models were built for all the monitored bridges. The backward analyses were carried out for all surveying epochs in the aim to define basic parameters of combined response – bilinear longitudinal resistance of track and the longitudinal stiffness of bridge support. The results serve both to evaluate the parameters defined in European standard EN 1991-2 for ballasted track and to complete the parameters for non-ballasted track.

continuous welded rail; track bridge interaction