Retexturing a Busy Bridge

Blastrac Global's largest shot blasting system, the Blastrac 2-4800 DH, recently played an integral role in resurfacing the Bernard F. Dickman Bridge, more commonly known as the Poplar Street Bridge. The bridge crosses the Mississippi River linking St. Louis (Missouri), with East St. Louis (Illinois). More than 120,000 cars drive across the bridge daily, so the project's success relied on completing it in a time-sensitive manner.

The job called for the removal of 1/4- to 3/8-inch thick T-48 low modulas polysulfide epoxy overlay with a broadcast aggregate. Over time, the epoxy and broadcast mix deteriorated, wore and flaked away, and a new overlay of epoxy slurry and broadcast aggregate was needed to make the bridge safe for the many cars that travel across it daily. The preparation of the steel girder bridge for a new overlay consisted of five steps: milling, sweeping, heating and scraping, sweeping again and shot blasting. The shot blasting portion of the retexturing job was performed by four 2-4800 DH - one owned by Tittarelli Inc., one machine owned by Venture and two machines owned by Surface Preparation Inc.

The project, which covered 280,000 square feet, began June 6 and was completed August 10. The project deadline was September 1. Crews worked six days a week for about eight to 10 hours daily on the project. Not only did the 2-4800s remove the existing coating from the steel bridge, its profiling capability increased the surface area and created an anchor profile in the steel for maximum bond strength and durability of the new coating.

"All parties involved in the Dickman Bridge in St. Louis were extremely pleased with the project's results," said Matt Shorrock, Blastrac Wheel Blast Product Manager. "It certainly proves that the 4800 is one of the most versatile and powerful shot blasters in the world. Shot blasting is necessary to profile a surface before it is resurfaced. The highlight of this machine is that it's highly mobile and compact. There are very few machines of this size that can do this type of work."

Dino Tittarelli, president of Tittarelli Inc., has owned a 2-4800 for five years and used the machine on various projects throughout the United States, from bridge and tunnels to airport runways. He said the 2-4800 was crucial in completing the Dickman Bridge project on time. Without the 2-4800, Tittarelli said the project most likely could not have been completed. He said one of the main benefits of the 2-4800 is the machine's versatility to work on large and small jobs.

"Right now I've got a 5,000-square-foot job and a 10,000-square-foot job to do with the 2-4800. The machine can handle these small jobs just as it can handle large projects like airport runways and the Dickman Bridge," Tittarelli said.

"It's good for every purpose, big or small whereas some equipment is so large that it can only do runway work. These other large machines won't get the job done on bridges," Tittarelli added.

The Blastrac 2-4800DH Shot Blasting System is designed for preparation of large concrete and steel surfaces such as highways, airport runways, bridge decks and ship decks. With a travel speed of 0-350 feet per minute and a 48-inch blast pattern, this machine strips, cleans and profiles up to 30,000 square feet of concrete, 40,000 square feet of asphalt or 7,500 square feet of steel, per hour. The machine's blast head adjusts side-to-side to allow blasting close to obstructions on either side of the machine giving the operator flexibility in tight areas and single lane closures. The 2-4800DH is powered by a 350 horsepower diesel engine, and uses twin centrifugal blast wheels to propel blast media in a controlled pattern and direction. Media is recycled for reuse, while an onboard 3,500 CFM dust collector gathers dust and debris.

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