CoatingsPro Magazine

MAY 2018

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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Page 51 of 92

COATINGSPRO MAY 2018 51 suspension bridges are anchored to massive concrete or rock structures on either side of the waterway, in self-anchored suspension bridges, such as the ree Sisters, the cables or eyebar chains are fastened to both ends of the bridge's longi- tudinal girders. ese girders provide compressive support in addition to stiffening the roadway. e ree Sisters bridges represent an innovative response to the challenge faced by the designers to comply with the War Department's mandate, create an aesthetically pleasing trio of bridges, and accommodate for the lack of adequate anchorage points along the banks of the A llegheny River. Just the Right Clearance e original bridge designers were not the only ones who faced a significant challenge when it came to river clearance. According to Skaroulis, a great deal of the blasting and coating work was done below the bridge deck. A 58,000-square-foot (5,388.4 m²) Safespan platform was constructed under the bridge deck in order for the crew to safely and efficiently blast and coat these areas. However, there were some complications during the construction of the platform. "e installation of our Safespan The 7th Street Bridge, also called the Andy Warhol Bridge, has a tight vertical clearance above the Allegheny River near PNC Park. That meant the crew had to coordinate extensively with the Coast Guard. Proper personal protective equipment (PPE) was worn throughout the project, including when working on scaffolding and lifts above deck. The crew used harnesses with double lanyards and rope grabs for 100 percent tie-off. JOB AT A GLANCE PROJECT: Rehabilitate the 7th Street (aka Andy Warhol) Bridge in Pittsburgh, PA COATINGS CONTRACTOR: Southern Road & Bridge, LLC 715 Wesley Ave. Tarpon Springs, FL 34689 (727) 940-5395 SIZE OF CONTRACTOR: 75 employees SIZE OF CREW: 11-40 crew members PRIME CLIENT: Allegheny County 542 Forbes Ave., Room 102 Pittsburgh, PA 15219 (800) 581-9145 SUBSTRATE: Steel CONDITION OF SUBSTRATE: Needed repair and rehabilitation SIZE OF JOB: ~200,000 sq. ft. (18,580.6 m²) of structural steel ~30,000 sq. ft. (2,787.1 m²) of buckle plate ~2,000 linear ft. (609.6 m) of galvanized steel handrail DURATION: August 2016-November 2017 UNUSUAL FACTORS/CHALLENGES: » The project had tight vertical clearance above the waterway. » It was near downtown businesses, pedestrians, and traffic. » The project required two separate mobilizations. MATERIALS/PROCESSES: » Abrasive blasted to NACE No. 2/Society for Protective Coatings (SSPC) Surface Preparation (SP) 10: Near-White Blast Cleaning » Spray applied much of the steel with Zinc Clad III at ~3 mils (76.2 microns), Macropoxy 646 Fast Cure Epoxy at 6-8 mils (152.4-203.2 microns), and Acrolon 218 HS Acrylic Polyurethane at ~4 mils (101.6 microns) » Coated the cells on the inside of the stiffening girder with Zinc Clad III Organic Zinc-Rich Primer and two coats of Macropoxy 646 Fast Cure Epoxy; some areas also received a coat of Epoxy Mastic Aluminum II at 2-3 mils (50.8-76.2 microns) » Pressure washed handrails above deck; hand ground; brush and roller applied Epoxy Mastic Aluminum II; and spray applied Micropoxy 920 Pre-Prime and polyurethane finish coat » Applied Zinc Clad III Organic Zinc-Rich Primer to buckle plates at ~4 mils (101.6 microns) and a stripe coat prior to the new rebar and concrete deck SAFETY CONSIDERATIONS: » Had a 58,000-square-foot (5,388.4 m²) Safespan platform installed » Used harnesses and rope grabs on scaffolding or lifts » Wore supplied-air hoods when blasting, respirators when mixing/coating

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