Method for determining the structural integrity of a bridge, comprising the steps of: - measuring deformations, such as displacements or rotations, during a predetermined time period with deformation measurement means arranged at or near supports of a bridge deck of the bridge, - determining the load configuration of the bridge deck over the course of the predetermined time period, such as the load configuration concerning the loading perpendicular to a longitudinal direction of the bridge deck, wherein the load configuration is derived from reaction forces measured by force measurement means arranged at the supports, - calculating the bending stiffness (EI) of the bridge deck over the course of the predetermined time period, from the load configuration and deformations measured by the deformation measurement means, and - comparing the bending stiffness (EI) at the end of the predetermined time period to the bending stiffness (EI) at the start of the predetermined time period to establish a difference in bending stiffness (EI) over the course of the predetermined time period; wherein the bending stiffness (EI) of the bridge deck over the predetermined time period is calculated based on a moving load passing over the bridge deck, such as a train or a car, comprising the steps of: - determining the type of load, - determining the position of the load, - determining the speed of the load, - calculating influence lines, - establishing kinematic relations between the load configuration of the bridge deck caused by the load and the forces measured by the force measurement means, and - calculating the bending stiffness (EI) of the bridge based on the load configuration resulting from the load and the deformations measured by the deformation measurement means at or near the bridge supports. - measuring deformations, such as displacements or rotations, during a predetermined time period with deformation measurement means arranged at or near supports of a bridge deck of the bridge, - determining the load configuration of the bridge deck over the course of the predetermined time period, such as the load configuration concerning the loading perpendicular to a longitudinal direction of the bridge deck, wherein the load configuration is derived from reaction forces measured by force measurement means arranged at the supports, - calculating the bending stiffness (EI) of the bridge deck over the course of the predetermined time period, from the load configuration and deformations measured by the deformation measurement means, and - comparing the bending stiffness (EI) at the end of the predetermined time period to the bending stiffness (EI) at the start of the predetermined time period to establish a difference in bending stiffness (EI) over the course of the predetermined time period; wherein - determining the type of load, - determining the position of the load, - determining the speed of the load, - calculating influence lines, - establishing kinematic relations between the load configuration of the bridge deck caused by the load and the forces measured by the force measurement means, and - calculating the bending stiffness (EI) of the bridge based on the load configuration resulting from the load and the deformations measured by the deformation measurement means at or near the bridge supports. <EOS>