When it was built in 1932, Cleveland's art deco-style Hope Memorial Bridge was hailed as one of the most beautiful bridges constructed that year. The historic landmark bridge spans the industrial Cuyahoga River Valley and is one of four major viaduct bridges that connect the east and west sides of Cleveland.
Since its last rehabilitation in the early 1980s, sections of the 3,285-ft-long bridge had deteriorated significantly. Its elegant arched steel trusses were rusted and damaged by an inadequate water drainage system, and the huge sandstone sculptures that stand sentry at the east and west entrances to the bridge were covered with years of dirt and beginning to spall.
While Cuyahoga County is responsible for the maintenance of the Hope Memorial Bridge, in 2000 the Ohio Department of Transportation (ODOT), District 12, stepped in to fund the $20.275 million, three-year rehabilitation project because of the project's scope and size. A key objective was to restore the bridge's appearance and preserve its beauty as an integral part of the cityscape--a project that would require stripping 1.8 million sq ft of steel to the bare metal and painting it with a three-coat system. A & L Painting LLC, Cleveland, was charged with this job.
Repairs to the structural steel and some of the concrete work were completed in 2001, while the focus of 2002 was on cleaning and painting the bridge's steel trusses. The final phase of the Hope Memorial Bridge project will be completed during the summer of 2003 when the concrete will be cleaned and painted and the bridge deck sealed with a crack sealer followed by a deck sealer, making the structure 100% watertight.
Art deco look
The Hope Memorial Bridge's high visibility prompted serious thinking about the colors to be used on the bridge's structural steel, parapet and pilasters. ODOT District 12 Design Engineer Natalie Conley, P.E., organized a team from a cross section of city and state planning commissions and from the Cuyahoga County Engineer's Office to select and approve the final bridge colors.
The team turned to The Sherwin-Williams Co. Color Marketing and Design Department for help. Color and Design Consultant Susan Wadden developed the color schemes from a palette of historic paint colors. As it happened, Sherwin-Williams is a Cleveland-based company, and Wadden's office overlooks the bridge. Using photo-imaging software, she superimposed different colors onto the bridge's steel trusses, parapet and pilasters.
"Plugging in the different colors gave the committee members a good feel for what each color scheme would look like," said Wadden. "We avoided the process of having to apply sample paint colors at the project site and then wait while the customer reviewed the colors, so we also saved valuable time."
The committee considered several color schemes and eventually selected a palette of green and tans. For the structural steel, Rookwood Dark Green, an olive-green shade, was selected and cross-referenced to the Federal Standard Color Number 595B-14097.
"Visually, it was a smart color choice as green appeals to 98% of the population," Wadden said. "The green color also complements the cityscape. Modular Tan was chosen for the railings, parapet and fascia, while Crewel Tan, which is several shades lighter, was chosen for the concrete piers."
The bare metal
Before the first coat of paint could be applied, a tremendous amount of surface preparation work was required to remove 70 years of accumulated paint. In February 2002, containment began at the first section of the Hope Memorial Bridge. To prevent airborne materials from escaping into the atmosphere and Cuyahoga River below, a containment tarp was custom made to fit the contours of the bridge. Schott International supplied the tarps for the bridge project and works exclusively with Sherwin-Williams in the sale and distribution of custom containment materials. Special cables and brackets were constructed to support the custom-made tarp, while a steel deck platform was installed below the steel trusses completing the containment system.
James Tuttle, P.E., vice president of operations for A & L Painting, explained, "As each section of the bridge is surface cleaned and painted, the containment cover and all of its support elements move together to the next section of the bridge to be painted."
In addition, the containment system was specifically designed to handle wind loads of 50 to 60 miles per hour as well as the weight of the contractor's materials stored at the project site. "Because of these preventive measures, there was no lost production time," Tuttle said.
A & L Painting crews started surface blasting with recyclable steel grit at the east end of the structure in April and worked their way to the west end by early October.
"They had to achieve bare metal-SPPC SP-10 near white blast--with a profile of existing steel between 1.5 and 3.5 mils," Tuttle said. "To meet the SPPC SP-10 standard, the steel had to be free of all visible oil, grease, dirt, dust, mill scale, rust, paint, oxides, corrosion products and other foreign matter, except for staining."
The interwoven design of the steel trusses, and the round rivets and bolts, presented a challenge for the crews who were forced to blast from several different angles to strip away the old paint.
"This work was more intensive, compared with blasting a rolled beam bridge that is one continuous piece of steel with flat surfaces and no rivets," Tuttle explained.
Layer upon layer
As soon as the steel was cleaned, the first coat of primer was applied within two hours to provide a protective barrier against future rust or other corrosion-related problems. The coatings used for the structural steel were supplied by Sherwin-Williams and manufactured to ODOT's Organic Zinc, Epoxy and Urethane System specifications. Paint batches were tested and certified by Sherwin-Williams quality control labs at the plant and tracked using ODOT's TE-24 (batch tracking) system. As a result, all paint supplies were registered with the state prior to arriving at the jobsite.
Kelly Tokish, a customer service representative with Sherwin-Williams, coordinated all the product orders and drop trailer shipments to the jobsite to ensure that adequate inventories of various materials were on hand at all times.
Selected for its corrosion-resistant properties, Zinc Clad IV Organic Zinc-Rich Epoxy Primer was used on the structural steel supports. It is a two-component, polyamide epoxy zinc-rich coating that features a low VOC level and 85% zinc content in the dry film.
"The Zinc Clad IV primer provides cathodic protection to the substrate of the steel," explained Mark Perrings, an industrial and marine sales manager with Sherwin-Williams. "If the coating system is damaged and bare metal exposed, instead of rust developing, a fine film of white powder (zinc oxide) forms and continues to protect the steel's substrate from corrosion."
Zinc Clad IV can be applied 5 to 8 mils wet (3 to 5 mils dry) and will be dry to the touch in about 30 to 45 minutes, depending on the temperature, humidity and film thickness. The organic zinc-rich epoxy primer can be top coated in only four to six hours.
Approximately 10,000 gal of Zinc Clad IV primer were applied to the structural steel of the Hope Memorial Bridge. About 36 miles of caulking was applied to channels and angles, plates, lattice bars, rivets and bolts.
The painting crews then proceeded with applying about 16,000 gal of heavy-duty epoxy intermediate coat. "The purpose of the intermediate coat is to seal the surface of the zinc, add 5 to 7 mils of barrier coat protection and provide a suitable surface for adherence of the topcoat," Perrings said.
Another 11,000 gal of paint were required for the finish coat--Hi-Solids Polyurethane Gloss--a two-component, low-VOC, aliphatic, acrylic polyurethane resin coating.
"Given the structure's high profile and visibility to motorists and downtown office building tenants, it was very important to select a coating that offered outstanding color and gloss retention," Perrings said.
The polyurethane offers chemical resistant properties that will protect the substrate from industrial and vehicular pollution for years. The recommended application is 4.5 to 6 wet mils and 3 to 4 dry mils. The coating dries to the touch in two to four hours and can be recoated within 18 to 24 hours.
The quality test
After each phase of surface cleaning and coating application, ODOT inspectors checked key criteria to ensure specifications were met.
"There are nine quality control points that ODOT inspectors monitor, and they cover every phase of the job from blasting to applying the finish coat," said Patrick J. McCafferty, transportation engineer, III, ODOT.
"For example, quality control point No. 4 is about abrasive blasting," he explained. "Inspectors measure temperature and humidity and calculate the dew point. In addition, they measure the surface profile of the steel to determine if it is within the 1.5 to 3.5 mils specified."
If spots are missed during the blasting phase, those areas are cleaned again and retested in order to pass a particular quality control point. Adhering to the nine control points helps ensure that quality work is performed at every step of the entire project.
The structural steel of the Hope Memorial Bridge was cleaned and painted by Oct. 31, 2002, meeting the project deadline. Final approval of all aspects of the three-year project, including the painting, will take place in the summer of 2003.
