FALL 2017

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

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Page 27 of 63

PROJECT Oakley C. Collins Memorial Bridge Design Development by Dr. Steven L. Stroh, AECOM The new Oakley C. Collins Memorial Bridge over the Ohio River between Ironton, Ohio, and Russell, Ky., replaces an aged bridge that opened in 1921. The original Ironton-Russell Bridge was a cantilever through truss bridge with a 725-ft main span. This bridge was at the end of its useful life and was rated both functionally and structurally obsolete. The bridge was restricted to vehicle widths of 7 ft 6 in. because of geometry restrictions, and was load-limited to 26 tons. Because of fatigue and fracture concerns, the bridge was continuously monitored. In 2003, the Federal Highway Administration issued a record of decision (ROD) for a replacement bridge on a new alignment. A design was developed for a new single-tower twospan cable-stayed bridge with a steel edge girder structural system and a 950- ft main span. This design was bid in 2006. The low bid was $109.8 million, whereas the state's budget estimate was $80 million. It was decided not to award the project and to implement a value-engineering process to try to get it within budget. Value Engineering The value-engineering process evaluated the current design and opportunities for optimization, assessed the project criteria driving the bridge type selection, and evaluated opportunities to refine the design solution within the requirements set by the ROD. The value-engineering team concluded that it was not possible to refine the original design solution, a single-tower cable-stayed bridge, to achieve the budget goals. A more comprehensive redesign would be required to achieve project goals. This included redesign as a balanced three-span two-tower cable-stayed bridge (which required reassessment of U.S. Coast Guard requirements on tower placement), change to a concrete superstructure, a reduction in typical section to the minimum required by the ROD, and improving the bridge alignment to facilitate the three-span bridge arrangement. As an outcome of this evaluation, the project was advertised for redesign in 2008. Reassessment of Navigation Requirements The original two-span cable-stayed bridge concept was driven by a navigation requirement that the pier (or tower) on the Ohio River bank could be no more than 50 ft from the bank. Because of the curving alignment as the bridge reaches the Ohio shore, a tangent alignment in the side span was precluded, which led to the decision for a two-span arrangement to keep the cable-stayed portion of the bridge out of a horizontal curve. As part of the value-engineering assessment, it was determined that with a slight realignment and, if the tower could be moved 100 ft off the Ohio-side bank, a tangent alignment for the side span for a three-span cable-stayed bridge could be accommodated. The U.S. Coast Guard was open to this reassessment and suggested navigation simulations to determine the acceptability of the tower location. Independent simulations were performed over a two-day period with three licensed river pilots piloting a 15-barge tow under a simulated bridge under a variety of navigation conditions. These included day and night, upstream and downstream, loaded and unloaded, and various river stage, flow, and wind conditions. The control simulations were run with the existing bridge; the new bridge was then inserted in the simulation with the tower at various distances from the Ohio-side bank and with varying skew angles for the tower. All simulations were run in the presence of U.S. Coast Guard personnel. The results of the simulation with the tower located 100 ft from the Ohio bank were favorable. Additional simulations were run with the tower 150 ft from the Ohio-side bank, which were also found to be acceptable from a river navigation viewpoint. As a result of the simulations, the U.S. Coast Guard approved the (cont. next page) PROFILE OAKLEY C. COLLINS MEMORIAL BRIDGE / IRONTON, OHIO BRIDGE DESIGN ENGINEER: AECOM, Cincinnati, Ohio NAVIGATION SIMULATIONS: Seaman's Church Institute, Paducah, Ky. PRIME CONTRACTOR: Brayman Construction Corporation Heavy Civil & Geotechnical Contractors, Saxonburg, Pa. CONTRACTOR CONSTRUCTION ENGINEER: Finley Engineering Group, Tallahassee, Fla. CONSTRUCTION ENGINEERING AND INSPECTION: FIGG, Tallahassee, Fla.

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