M.Polák

Czech Technical University of Prague, Czech Republic

ABSTRACT: The main results of an experimental and theoretical study of a dynamic behaviour of a prestressed concrete road bridge are described in this paper. The investigated bridge was built in 1979. Today this bridge is under heavy load. The bridge is the slab structure which is designed as a two span continuous girder. The lengths of spans are 25 and 27 m. The experimental modal analysis of this bridge was executed repeatedly (in April 1997 and in May 1998). The results of the both modal analyses were compared. Further the passages of two trucks over the bridge were carried out in April 1997. The results of the dynamic tests of this observed bridge are valuable by reason that few data are mentioned about similar bridges with relatively small lengths of spans. The results of an experimental investigation of the bridge were used for the identification of the bridge design model. The experimental frequencies and modes of natural vibration were utilised for the creation of the spatial modal model of this bridge. This paper also presents that the direct use of the experimental modal data of a bridge for the calculation of its response to a dynamic load is possible to use for the study of the vehicle/bridge interaction problem.