Sunshine Skyway Bridge | St Petersburg, Florida
Check out this great historic TriLock Block project! This job was done about 26 years ago. This is a scour protection project at the base of the Skyway Bridge in St. Petersburg, Florida.
The slopes and abutments of the new Sunshine Skyway Bridge will resemble backyard patios after new high-tech erosion control blocks are installed.
The blocks, called Tri-Lock, are one of the latest tools the State Department of Transportation (DOT) is using to curb erosion, and the Skyway is one of the first and largest projects where the concrete blocks will be installed.
The interlocking blocks proved their worth on the Skyway during Hurricane Elena, officials say. Some of the devices were already installed on part of the south approach to the new bridge when Elena battered Pinellas County on Labor Day weekend. A detour road and adjacent approach areas were washed out, but the slope protected by Tri-Lock was not damaged.
Manufactured by Gator Culvert Co. in Sanford, the blocks cost about $42 per square yard, Holly Waggoner, DOT Skyway project spokeswoman, estimates that the 11,710 square yards of stone – $491,000 worth – will be used on the new bridge. “The Skyway is the first time our eight-inch thick blocks have been used in Florida,” says Joe McCloskey, Gator Vice President. “The eight-inch blocks provide significantly more wave protection.”
For anchoring purposes, the blocks interlock and resemble a gigantic jigsaw puzzle. McCloskey says the blocks are one of the first erosion control devices to use an interlocking rather than a cable anchoring system.
The blocks which are shaped like three-leaf clovers and weigh about 60 pounds per square foot, are cheaper than erosion control methods originally specified for the $220-million bridge. However, after testing Tri-Lock the DOT decided to allow Ballenger Corp., the firm building the bridge’s approaches and trestles, to install the new blocks on the Skyway.
Tri-Lock is installed over a plastic filter blanket, which is a woven sheet that holds earth in place and permits water to drain in and out of the blocks. The connecting blocks form to the contour of a slope or abutment. Gaps in the blocks can be filled with dirt to permit vegetation to grow or with gravel.
-By JANE MEINHARDT