Assessing the Scouring Depth and Health Condition of Bridge Foundation Through the Field Monitoring and Associated Structural Modelling
Date Issued
2012
Date
2012
Author(s)
Li, Kai-Wen
Abstract
Most bridges of western Taiwan have faced with the problem that the foundations were exposed due to the flood scour. Typhoon Sinlaku in 2008 and Typhoon Morakot in 2009 caused damage to the bridges. Existing systems can only monitor the water level. However, it didn’t reach the water level criterion to close the bridge when Bridge Hou-Fong and Bridge Shuang-yuan collapsed. It seems that using water level to determine the safety of the bridge is not adequate.
In the study, using the vibration frequency, amplitude, inclination of Bridge Ci-bing and water level, flow velocity of the river to assess the health condition of bridge foundation. The loss of soil around the foundation due to the flood scour will cause the decrease of bearing capacity.
In terms of monitoring, establish real-time monitoring system to measure the vibration frequency, amplitude, inclination of Bridge Ci-bing and water level, flow velocity of the river. In terms of analyzing monitoring data, Write an automated program by Labview to process large data. Then create a database with dayfile and weekfile to do further analysis. This study proposes a frequency identification analysis method which can show the health condition of the bridge clearly, and use the method to analyze the data of typhoon event.
In terms of model analysis, modeling by SAP2000 after collecting basic information of the bridge. Then correct model by nature frequency and modal shape which measured in field test. After correcting model, we can simulate structure behavior. Then compare effects to the bridge of the three physical parameters , water level, flow velocity and scouring depth, and combine with monitoring data to assess the critical condition of the bridge.
Subjects
Structure health monitoring
Exposed foundation
Scouring
Nonlinear pushover analysis
Type
thesis
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