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Cause Estimation of Damages in Pathein Suspension Bridge Based on Vibration Measurements
* 1 , 2 , 2 , 2
1  Institue of Industrial Science, The University of Tokyo
2  Institute of Industrial Science, The University of Tokyo


Pathein suspension bridge situated in Pathein city in the south of Myanmar has shown various symptoms of damage and the safety of the bridge is questionable. The authority concerned reported that the bridge is undergoing severe deteriorations since its construction, namely towers’ inclination, excessive deflections, bearing failure, heavy corrosion of main cables and hangers, hangers’ inclination, and slippage of clamps. The deformed shape of the stiffening girder was found to be unusual with maximum deflection nearer to the towers, however, in a single span bridge, such as Pathein bridge, the maximum deflection is expected to be at mid-span. This paper could estimate the possible reasons for the unusual excessive deformations in the stiffening girder and bearing failure. Tension force of hangers was estimated based on vibration measurements, the distribution of hangers’ force was found to be non-uniform with low-tension force in hangers closer to the towers. The non-uniform distribution of the hangers’ tension force is possibly due to shortcomings of the design of the cable system. Towers’ inclination has caused the road level to drop down, however, the unusual deformations in stiffening girder are attributed to the non-uniform distribution of tension force in hangers. Low-tension force in the hangers near towers caused the bearing to carry excessive force, which eventually caused the bearing to fail, the bearing was rehabilitated by adding steel rollers.

Keywords: Suspension Bridges; Structural Deterioration; Tension Force Estimation; Accelerometer; Vibration Measurements; Cause Estimation.