was constantly exposed to high winds. Some of the falsework timbers were . It took two months to construct the falsework alone. When high waves threatened the falsework foundation, construction was halted for a short time until winter storms abated. The crews excavated of earth and rock. Eight hundred and twenty-five trucks brought in 600,000 pounds of reinforcing steel. Sand and gravel were supplied from a plant in Big Sur. Construction required 45,000 sacks or of cement which was transported from Davenport, near Santa Cruz, and from San Andreas. Crews began placing concrete on November 27. The concrete was transported across the canyon on platforms using slings suspended from a cable above the creek. The bridge was completed on October 15, 1932, although the highway was not finished for another five years. At its completion, the bridge cost $199,861 and, at , was the longest concrete arch span on the California State Highway System. The bridge was necessary to complete the two-lane road which opened in 1937 after 18 years of construction. The completion of construction was celebrated with a ribbon-cutting ceremony led by Dr. John L.D. Roberts, who had conceived of the need for the road. Rainbow Bridge After the bridge was completed, it was at times known as the Rainbow Bridge, due to the presence of the Rainbow Lodge resort on the creek upstream from the bridge. It was operated by former Army Captain Howard Sharpe and his wife, Frida. After timber harvesting was no longer profitable, Sharpe bought the Bixby Creek Canyon ranch in 1919. He built a dirt road from the lodge up the canyon to Bixby Landing and another road down to the beach at the mouth of Bixby Creek. He sold part of his land to the state as part of the bridge right-of-way in 1930. When the bridge was completed and tourists no longer needed to descend to his lodge on the creek, he built a new lodge on the highway north of the bridge. Seismic retrofitting The bridge was retrofitted beginning in 1996 with an analysis by bridge engineering company Buckland & Taylor as part of the Caltrans Phase II seismic retrofit program. In their detailed evaluation of the bridge's seismic vulnerabilities, they were challenged to find a solution that met several difficult issues, including severe load factors, extremely limited physical access, maintaining the appearance of the existing historical structure, and a