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 PITTSBURGH, June 15 /PRNewswire/ -- Despite the $150+ billion that the 1991 Federal Transportation Act will inject into the nation's transportation system, bridges in the United States will continue to deteriorate in this decade, according to a new national survey of bridge designers and managers.
 About half of the bridge professionals said there would be an increase in the number of structurally or functionally deficient bridges in the country by the end of the decade. The U.S. Federal Highway Administration's 1991 report placed the number of spans now in this unsound category at 40 percent.
 Findings of the survey, sponsored by Miles Inc., of Pittsburgh, are being reported in conjunction with the 1992 International Bridge Conference and Exhibition being held June 15-17 at the Pittsburgh Hilton Hotel. The survey was conducted by Industrial Research Center, of Homestead, Pa., an independent polling organization.
 To combat rising bridge deterioration, to avoid field-related environmental problems and to improve speed, safety and quality control, the respondents said they would employ various measures. Included would be off-site fabrication and coating of steel components, concrete bridge construction, use of high-performance, long-lasting polyurethane coatings and other corrosion-resisting paints, and special materials to resist premature decay of concrete bridge decks.
 These are the opinions expressed in reply to questions, on broad- based technical, material and procedural changes expected in bridge design and maintenance protection, mailed to 1,240 bridge professionals selected at random. About 350 replied, and 202 questionnaires were received in time to be tabulated. This group included 145 (74 percent) professionals at highway departments, bridge authorities and other government agencies, and about 50 (25 percent) at bridge design and consulting firms.
 The survey findings are being announced by Jack J. Bracco, market development manager, maintenance and construction coatings for Miles. The company supplies the paint and coatings industry with raw materials to formulate high-performance polyurethane coating systems for bridges and other structures.
 Nearly half (47.5 percent) of the bridge professionals surveyed predicted a rise in the number of structurally or functionally deficient bridges nationwide by the year 2000. Bridges will continue to deteriorate at a high rate, they said, because of past neglect, still- inadequate funding for bridge maintenance, and maturation of bridges built during peak years of construction.
 Polyurethane Topcoats Widely Cited for Corrosion Resistance.
 To help protect bridges against damaging environmental attack, corrosion-resisting paints were called the most effective deterrents by the largest number of bridge professionals (43.6 percent). Replacing salt as a deicing medium (31.2 percent), and penetrating sealers to stop the spread of corrosion (14.4 percent), followed in that order.
 Among the corrosion-resistant paints, about 60 percent of the bridge authorities ranked three coating systems, each utilizing a polyurethane topcoat, as the most effective in maintaining protection performance, in resisting acid rain, and in retaining color and gloss.
 The highest rated coating system was the one with an inorganic zinc primer, epoxy intermediate and an aliphatic polyurethane topcoat. This system received a "most effective" ranking from 37.1 percent of the respondents. Polyurethane zinc/polyurethane/aliphatic polyurethane systems were the second most favored, and epoxy mastic/epoxy mastic/aliphatic polyurethane systems were third. A three-coat epoxy was close behind, followed by inorganic zinc/vinyl/vinyl, a three-coat alkyd and a three-coat acrylic emulsion.
 Coating Life Cycle Critical.
 "The survey clearly reflects the importance of high-performance coatings in helping both to preserve the bridges we have," said Bracco, "and to extend the life of the next generation of bridges. More than 90 percent of those surveyed indicated that coating life cycle was most (56.4 percent) or moderately important (35.6 percent) in choosing a coating system."
 Epoxy coatings and galvanizing bars were seen as the most effective system for resisting premature deterioration of concrete bridge decks (72.8 percent). Other most-mentioned protective methods included "increasing bar cover thickness" (46 percent), "reducing water/cement ratios" (42.1 percent), "increasing densities" (40.1 percent), and cathodic protection (29.7 percent).
 Concrete Bridges Will Dominate New Construction.
 Most of the new bridges built in the 1990s that will carry cars, trucks and other vehicles into the 21st century will be made of concrete, the survey finds. When asked which types of bridges will dominate construction in the current decade, 83.2 percent named concrete bridges, dwarfing the other types: cantilever spans (24.3 percent), cable-stayed bridges (23.8 percent), steel-truss spans (19.8 percent) and steel suspension bridges (3.5 percent).
 Currently, 203,400 of the nation's 471,000 bridges (20 ft. or longer) are made of steel, or 43 percent of the total. Some (5.2 percent) of these bridges date back to the 1800s, testifying to the longevity of steel construction.
 Of the steel bridges now in use as listed in the 1991 Federal Highway Administration report, 125,091 (61.5 percent) were built 30 or more years ago, Bracco pointed out. "Obviously, these structures need careful, regular inspection, periodic rehabilitation, and continuing maintenance paint protection to enable them to resist corrosion and atmospheric attack," he said.
 Coating Performance Judged Most Important.
 Respondents to the survey predicted that VOC (volatile organic compound) emission levels for paints used in new construction will become more stringent and will be lowered to an average of 2.5 lbs./gal. by 1995. Bridge professionals also said that the primary requirement for bridge coating systems will remain strong performance properties.
 Overall, 50 percent ranked performance as the most important factor in selecting a coating system and 37.6 percent ranked VOC levels and performance equally.
 A significant number of the bridge professionals (42 percent) plan a moderate increase in the performance of the coating systems they use, while 16.3 percent plan an extensive increase.
 "It is interesting," noted Bracco, "that the same survey that predicts increased reliance on high-performance corrosion-resistant coatings, and lowering VOC levels, also expects improvement in paint systems. The respondents demonstrate a faith in the continued development of high-performance, low-VOC coatings."
 Reactions to Waterborne Systems.
 The relative newness of waterborne paint systems, developed to replace solventborne systems, was reflected in the replies to a question about the prospects for their use in coating bridges. The greatest number, 45 (22 percent) suggested that the products showed promise and are open to development.
 Twenty-six (13 percent) said they had no knowledge of the systems and that test data were needed; 23 (11 percent) said that they thought that the waterborne systems will increase to the point of domination, and 20 (10 percent) identified themselves as users of waterbornes. The others surveyed did not reply to the question.
 Preferred Methods for Repainting Corroded Bridges.
 When repainting a bridge that has been coated originally with lead paint, the preferred repair method depends on how much of the bridge was corroded, the group stated. When corrosion exceeds 25 percent of surface area, respondents (48 percent) favored complete removal, containment and safe disposal of the old paint and blast particles. With Number 1 being specified as the first preference for comparative purposes, this complete removal technique was rated 1.6 out of a possible four. When the damage is more limited (25 percent or less), the preference (46 percent) is for cleaning, spot repair and overcoating the entire span. Here the preference ranking was 1.5 out of four.
 In the field, the use of brushes and rollers to avoid overspray problems is favored by approximately 45 percent of respondents for painting 25 percent of a bridge's surface area or less. When the amount of surface area to be covered rises above 25 percent, the use of brushes and rollers drops dramatically, down to between 5.4 and 10.4 percent, depending on the percentage of surface area which requires painting and the application methods used.
 In-Shop Fabrication and Coating is Increasing.
 Another trend indicated by the survey is increasing use of off-site or in-shop fabrication to cut costs in new bridge construction projects, improve speed, safety and quality control and to avoid field-related environmental problems.
 About 50 percent of the bridge professionals said that 51 to 100 percent of their new work involves off-site or shop prefabrication. "Significantly, 48.5 percent of the respondents report that more than 75 percent of steel painting is taking place in-shop," Bracco added.
 1991 Transportation Act Creates New Business for Bridge Crews.
 Of the 1991 Federal Transportation Act's $150+ billion to be spent on revitalizing American transportation facilities, respondents said that they expected to receive a total of about $2.8 billion from an average of 30 rehabilitation projects each.
 Respondents also expect to participate in an average of 37 new bridge projects each, for which they will receive federal funding totaling about $2.5 billion.
 "How this money is spent will have an enormous impact on the future of this country," said the Miles market development manager. "This survey indicates a strong awareness of performance, environmental and safety issues among industry professional, and that key criteria such as reduction of atmospheric pollution and VOC levels, as well as the increase of coatings' life-span and corrosion resistance are being addressed in a serious, straightforward manner.
 "If the federal funds are allocated wisely," Bracco continued, "to help provide protection of new structures, to establish continuing maintenance programs, and to promote the sensible, environmentally sound cleaning and repair of deficient bridges, we should never have to see a time in which more than 40 percent of our bridges are considered structurally or functionally deteriorated again."
 Miles Inc. is a Fortune 100, research-based company with major businesses in chemicals, health care and imaging technologies. Headquartered in Pittsburgh, Miles employs some 30,000 people at its operations throughout the United States and Canada. In 1991, the company's sales were $6.2 billion.
 -0- 06/15/92
 CONTACT: Carol Stein of Miles, 412-777-2496; or Norman Schorr, 212-935-5555, for Miles CO: MILES INC. IN: CHM ST: PA -- NY008 -- X454 06/15/92
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Date:Jun 15, 1992

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