This article investigates the dynamic behaviour of a pedestrian timber truss bridge by in situ testing and numerical modelling. The in situ dynamic tests were performed at three different construction stages: (1) on the finished bridge without the asphalt layer, (2) on the finished bridge with the asphalt layer at warm conditions and (3) same as stage 2 but at cold conditions. The interest of this study is that some modelling details that are usually not considered in the numerical modelling of pedestrian timber bridges are important for this bridge. The stiffness at the connections must be considered in order to obtain accurate numerical results for both lateral and bending modes. The stiffness of the pile foundations has an influence on the first bending mode. In addition, the experimental damping ratio for the first lateral mode is much higher than the values recommended in the design codes.