摘要: |
Having been partially submerged for several decades, the girders of the I-10 Littlewoods Bridge have become a safety concern due to structural deterioration. As a response, Louisiana Department of Transportation and Development (DOTD) initiated a rehabilitation project that utilized external post-tensioning using both high-strength steel rods and Carbon Fiber Composite Cables (CFCC) as the secondary support. Instrumentation including thermistors, strain gages, and load cells were installed to monitor the behaviors of the girders. Based on the data collected within the monitoring period, the rehabilitation effort appears to be functioning as design by slowly transferring load to the external support system. There are several observable differences between the high strength steel rods and CFCCs. However, without a clear baseline, it is very difficult to determine the causes of the differences. Many factors, such as anchorage installation, structural conditions, and instrumentation types, could have contributed to the behavior differences. Both materials appear to be functioning as designed. CFCCs have the advantages of smaller thermal effect; thus, the interpretation of the structural performance is less impacted by the temperature effect. Steel rods have the cost advantage and prove to be as effective in supporting the structure at least in the short term. Due to the short observation period, the long-term behaviors of the steel rods and CFCCs should only be determined after longer monitoring period. |