There was very little degradation after all those years. Aluminum's lighter weight also results in speedier deck installation, an increasingly important factor given the congestion-weary public's attitude toward road construction delays. And shorter downtime equates to cost savings in the form of less traffic control, fewer accidents, and greater productivity. According to a study conducted by Alcoa in the 1980s, the average downtime for a bridge receiving an aluminum deck was 24 days. Compare that to 10 to 12 months for a comparable job using concrete.
Bubbles indicate buckling failure of the rib plates under wheel load.
However, the load that caused the failure was about eight times the legal truck wheel load. Aluminum also is more ductile than most bridge materials, making it an excellent candidate for use in areas with moderate to high seismic risks. The material is easily configurable to any number of shapes and sizes, and it boasts a high salvage value when replaced. Plenty of Potential for Both Past and Future Bridges D epending on which statistics you believe, there are between 250,000 and 600,000 bridges in the United States in need of significant repair. Of these, more than 65,000 suffer from structural deficiencies, and another 12,000 have weight restrictions placed on them.