Heavy traffic on the bridge cause not only static effects, but also dynamic effects. These effects can be indicated by different dynamic parameters like -natural frequency, bridge logarithmical decrement, bridge acceleration and dynamic amplification factor (DAF). Dynamic amplification factor is the most widely used parameter, because it shows amplification of the static effects on the bridge structure. Results show that for bridges road surface condition is a very important factor. If road surface contains ice bumps or potholes then heavy traffic driving with low speed can decrease load carrying capacity of a bridge.

No abstract

No abstract

Dynamic properties of the bridge superstructure vary depending on many characteristics of the bridge and the loading conditions. In this paper, maximum Dynamic Amplification Factor was calculated for six different types of typical pre-stressed concrete beam bridges. It showed that each type of bridge with similar loading has a different range of Dynamic Amplification Factor. At the same time, every recently built bridge has different geometry and design load. Hence, it is difficult to determine a characteristic value of Dynamic Amplification Factor for the similar type of structures. By using fullscale dynamic and static bridge tests, it is possible to determine the necessary characteristics which show possibly high Dynamic Amplification Factor. This factor indicates if it is necessary to make a full-scale bridge dynamic analysis. It was found that those characteristics are natural frequency (first mode), damping ratio, relative deflection, and span and depth ratio. Obtained results from tests show a range of values for each of the characteristic. These ranges were analysed for reinforced concrete slab and pre-stressed concrete slab, and girder bridges.

No abstract