Condition Assessment of the Eastbound 6th Avenue Viaduct Using Strain Gauges

This paper presents the procedure and results of a strain gauge study completed on the eastbound 6th Avenue Viaduct in Denver. The 6th Avenue Viaduct was modified in a 1997–1998 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 in the winter of 1999–2000 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 two concrete crack gauges. Data were taken for a period of 3 months. Analysis of the data suggests that the bridge is safe for short-term use, but that the long-term viability of the structure has been compromised. Repair or replacement of substructure elements is recommended, along with frequent monitoring during the interim period.