Structural health assessment and restoration procedure of an old riveted steel arch bridge

Structural health assessment of the old bridges is very important because of the fact that some bridges have been damaged or destroyed in the world every year. The paper presents the structural health monitoring, safety identification and restoration proposals for an old riveted arch steel bridge. The selected bridge is named as Borçka Steel Arch Bridge and it is located in Artvin, Turkey. Firstly, in-situ structural investigations on the bridge are presented. Then ambient vibration test are carried out on the Bridge in order to determine the experimental dynamic characteristics called as the natural frequencies, mode shapes and modal damping ratios. The measurement is performed under the environmental effects of pedestrian movement and wind-induced vibration by using uniaxial seismic accelerometers. The accelerometers are placed to the bridge deck in both the vertical and horizontal directions. The initial finite element model developed according to the building survey data is updated by using the dynamic test results. The updated finite element model is analyzed for the different load cases including dead, moving, wind and earthquake loads. Restoration recommendations are made according to the results from site investigations and analysis. The existing and restorated models of the bridge are checked to the design criteria in AISC-ASD 89 (1989).