Sunshine Skyway Bridge
When people come to the coast of West Florida, they come for the sun and the seascapes. They don't always come with the intention of marveling at the architecture, but what if you could see sun, sea, and building all rolled together? Well, you can.
The Sunshine Skyway Bridge (which is a very optimistic name for a bridge) stretches 29,040 feet from St. Petersburg to Bradenton, Florida, which is over four miles, most of it across the mouth of Tampa Bay. It's an amazing sight, a shining compliment to the sunshine and seascapes of West Florida.
History of the Bridge
The history of the Sunshine Skyway Bridge begins with its predecessor, a steel cantilever bridge of the same name. The old bridge guarded over Tampa Bay for almost 30 years until May 9, 1980, when a terrible thunderstorm smashed the freighter Summit Venture into the bridge. Over 1,000 feet of the bridge collapsed into the water, killing 35 people.
The 1980 disaster was a major tragedy, and the state realized that a new bridge was needed. Demolition crews were brought in to safely destroy what remained of the bridge. The supports were later turned into fishing piers. A new bridge was designed primarily by Figg and Muller Engineers, with lower-level sections created by several other firms.
However, this new bridge would not look like the old one. In fact, it would be a different kind of bridge entirely. The original bridge was a cantilever bridge, in which steel trusses supported the weight of the load-bearing deck. The new Sunshine Skyway Bridge, on the other hand, would be a cable-stayed bridge.
A cable-stayed bridge is one in which cables extend directly from towers or pylons along the bridge and connect to and support the load-bearing deck. This makes them different from other cable-based bridges (like suspension bridges, in which the deck is suspended from cables attached between multiple towers).
Construction of the new Sunshine Skyway Bridge began in 1982. Over 300 precast concrete segments were transported to the site and quickly linked together with the cables anchored to massive towers. Twenty-one steel cables extend from each direction of the towers, supporting the weight of the concrete slabs. Each cable is encased in nine-inch-diameter steel pipes. In fact, the entire bridge is almost completely composed of just concrete and steel, making it the longest cable-stayed concrete bridge in the world.
At a cost of $244 million, the bridge opened in 1987, making it a very rapid construction project considering the size of the structure. Since then, the bridge has been lauded for its design, which includes some very unique elements, most focused on the central span of the bridge. The cables descending from the two towers of this span are set in the middle of the bridge, with 40-foot roadways on each side. By placing the cables here, instead of on the edges of the bridge, the designers ensured that motorists would always have an unimpeded view of the bay. As a final touch, the cable cases were all painted bright yellow, representing rays of sunshine in the Sunshine State.
Sunshine Skyway Bridge Design
The design of the Sunshine Skyway Bridge is well worthy of praise, but that pales in comparison to the efforts taken to make this bridge as safe as possible. Considering what happened to the old bridge, the obsession with safety is understandable. The designers started by raising the bridge 50% higher, building it 190 feet above the water so that ships could safely pass underneath.
But what if a ship hits one of the main supports? To prevent a disaster like the one in 1980, concrete islands, called ''dolphins,'' were installed around each of the six piers that keep the bridge upright. These dolphins were designed to withstand the force of an 87,000-ton ship, thus preventing anything from actually hitting the bridge itself. For reference, the Summit Venture only hit the old bridge with a force of roughly 20,000 tons.
With these safety measures in place, the Sunshine Skyway Bridge opened to the public, and remains a source of pride and fascination to this day. Roughly 52,000 vehicles cross it every day. Corrosion of the concrete and steel have been a problem (as is common in saltwater), but regular maintenance keeps the bridge exactly as Florida wants it: bright, shiny, and above all, safe.
Lesson Summary
All right, let's take a moment or two to review. The Sunshine Skyway Bridge is a four-mile-long cable-stayed bridge stretching across the mouth of Tampa Bay, Florida. Composed almost entirely of steel and concrete, it's the longest cable-stayed concrete bridge in the world, with a cable-stayed bridge being one in which cables extend directly from towers or pylons along the bridge and connect to and support the load-bearing deck. The bridge was created to replace a former bridge that was hit by a freighter in 1980.
Made largely of prefabricated parts and completed in 1987 at a cost of $244 million, both design and safety were major priorities. The massive cables that support the deck tether to the middle of the bridge, allowing for unobstructed views of the bay, and are painted bright yellow to represent rays of sunshine. The bridge is taller than its predecessor, and each pier is surrounded by concrete ''dolphins'' that can withstand 87,000 tons of force.
