Bixby Creek Bridge

Bixby Bridge, also known as Bixby Creek Bridge, is a bridge on the Big Sur coast of California. It is one of the most photographed bridges in California, because of its aesthetic design, "graceful architecture and magnificent setting". It is a reinforced concrete open-spandrel arch bridge. The bridge is 120 miles (190 km) south of San Francisco and 13 miles (21 km) south of Carmel in Monterey County on State Route 1. The bridge opened in 1932. Before then, the residents of the Big Sur area were cut off during winter due to blockages on the often impassable Old Coast Road, which led 11 miles (18 km) inland. The bridge was built under budget for $199,861 (equivalent to $3.16 million in 2020 dollars) and, at 360 feet (110 m), was the longest concrete arch span in the California State Highway System. When it was completed, it was the highest single-span arch bridge in the world, The land north and south of the bridge was privately owned until 1988 and 2001. A logging company obtained approval to harvest redwood on the former Bixby Ranch to the north in 1986, and in 2000 a developer obtained approval to subdivide the former Brazil Ranch to the south. Local residents and conservationists fought their plans, and both pieces of land were eventually acquired by local and federal government agencies. A $20 million seismic retrofit was completed in 1996, although its 24-foot (7.3 m) width does not meet modern standards requiring bridges to be 32 feet (9.8 m) wide. Characteristics The bridge is 714 feet (218 m) in total length and 24 feet (7.3 m) wide, with 260 feet (79 m) of clearance below, and has a main span of 360 feet (110 m), which places 50% of the total roadbed above the arch. The arch ribs are five feet thick at the deck and nine feet thick at the springing line, where they join the towers at their base. The arches are four and one-half feet wide. The bridge was designed to support more than six times its intended load. The two large, vertical buttresses or supporting pillars on either side of the arch, while aesthetically pleasing, are functionally unnecessary. Engineers of later arch bridges such as the Frederick W. Panhorst Bridge omitted them from the design. The Rocky Creek Bridge and the Malpaso Creek Bridge to the north are also open-spandrel arch bridges built of reinforced concrete. Construction The state first began building Route 56, or the Carmel–San Simeon Highway, in 1919. A number of bridges needed to be constructed, the largest among them across Bixby Creek. Bridge design State engineers considered two alternatives to crossing the creek, an inland route and a smaller bridge, or a coastal location and a larger bridge. The inland route would have needed an 890-foot (270 m) tunnel cut through the Santa Lucia Mountains to a 250-foot (76 m) bridge upstream. The engineers selected the coastal route because it was safer, more scenic, and least affected the environment. California state highway engineer C. H. Purcell and bridge engineer and designer F. W. Panhorst considered whether to build a steel or concrete span. A steel bridge would cost more to build and maintain, as the sea air would require expensive ongoing maintenance and painting. A steel bridge was also less in keeping with the natural environment. Using concrete reduced material costs and allowed more of the total cost to be paid to workers, which was a positive aspect of the design during the Depression. They chose concrete in part because it would not only reduce both construction and maintenance costs but would also echo the color and composition of the natural rock cliff formations in the area. Design and materials 4,700 cubic yards (3,600 m3) of earth and rock were excavated 600,000 pounds of reinforcing steel and 6,600 cubic yards (5,000 m3) of cement were used to build the bridge. The bridge was built by Ward Engineering Company of San Francisco and dedicated on November 27, 1932. The bridge was necessary to complete the two-lane road which opened in 1937 after 18 years of construction. References Other websites Pelicannetwork.net: Big Sur Bixby Bridge Popular Mechanics (April 1933) — Concrete Arch bridges California Canyon