Let's go back to 1980
Before the Pennybacker Bridge was built, Austin's 360 highway dead ended into Lake Austin.
The way Austin's most recognizable bridge came to be....
The south section of Loop 360 from US 290 to RM 2244 was opened on February 11, 1970. The last section of roadway for Loop 360 (excepting the bridge) between RM 2244 and FM 2222 was approved on September 30, 1976. The north and south sections of Loop 360 were connected when the Pennybacker Bridge was opened for traffic on December 3, 1982.
The steel bridge has a uniform weathered rust finish allowing the bridge to blend in with the surrounding hills and lake. The 600 short tons (544,311 kg) of steel for the bridge were produced in Japan. The bridge structures were fabricated in Ulsan, Korea by Hyundai Heavy Industries. The steel structures were shipped on the Jundale freighter to the Port of Houston and then trucked to the bridge site. The bridge was erected by Bristol Steel of Bristol, Virginia. The roadway surface is built from 3,400 short tons (3,000,000 kg) of concrete. The finish was sandblasted to ensure even weathering for an amber patina. The construction was coordinated by Clearwater Constructors (Hensel Phelps) of Denver, Colorado. Ed Westall was the project coordinator, Buddy Johnson was the project supervisor and David McDonnold was the bridge designing engineer. The bridge cost US$10 million to build.
The bridge is constructed such that no part of the structure touches the water 100 feet (30 m) below. The bridge is 1,150 feet (351 m) long with a 600-foot (183 m) central arched span. This design keeps Lake Austin free from support columns because the recreational lake (really a dammed stretch of the Colorado River) is popular with boaters and waterskiers. The untied arch suspension span is suspended by 72 steel cables. At the time of its construction, it was only the second bridge of its design in the world.
The bridge has four lanes, two in each direction, separated by a middle barrier wall. The bridge also has a 6-foot-wide (1.8 m) bike and pedestrian lane. The bike access on the bridge is one reason for Loop 360's popularity with cyclists. The south approach provides a turnaround under the bridge along with lake access for public boating.
The bridge won first place in the 1984 Federal Highway Administration's Excellence in Highway Design competition. In 1992, the Austin members of the Consulting Engineers Council of Texas were surveyed and selected the bridge as the most innovative example of Austin architecture.
Meet the Designer
Percy Pennybacker worked for the Texas Highway Department in the early 1900s designing bridges. He earned his civil engineering degree from the University of Texas at Austin. He served as a captain in the Army Air Service during World War I. After the war, he worked in Kansas and Texas. During World War II, he became interested in welded construction as an alternative to rivets. By promoting the use of welding for heavy stress bridge design, he is credited with saving the state of Texas millions of dollars.
When he retired from the Texas Highway Department, he worked another three years for the city of Austin as a civil engineer.
He was honored as "Outstanding Engineer" by the Texas Society of Professional Engineers, was a member of the American Society of Civil Engineers, and brought the American Welding Society to Austin.