Structural Evaluation and Repair of the 6th Avenue Viaduct

This paper presents an overview and results of a strain gauge study conducted on the eastbound 6^th Avenue Viaduct Bridge in Denver, Colorado and a general description of the subsequent repair. The 6^th Avenue Viaduct was modified in a 1997–98 rehabilitation making the entire superstructure continuous. New sliding bearing pads failed to properly accommodate expansion and contraction of the bridge superstructure due to temperature changes. Visible damage due to contraction of the superstructure prompted a study of substructure elements to determine the short-term safety and long-term viability of the bridge. Substructure elements were instrumented with a total of 62 strain gauges and 2 concrete crack gauges. Data were taken for a period of three months. Results of the study suggest that the bridge is safe for short-term use, but that the long-term viability of the structure has been compromised. Interim strengthening of critical substructure elements were conducted and replacement of a substantial portion of the substructure on the west half of the bridge will commence in the summer of 2003. Results of the study were used in design to verify assumptions and target these repairs.