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.
Issue link: http://www.aspiremagazinebyengineers.com/i/306186
The Stewart St. Bridge over the Great Miami River in the city of Dayton, Ohio, is adjacent to the University of Dayton. The original structure was constructed in 1911 by Gephart and Kline. It was designed by the Concrete- Steel Engineering Company of New York, N.Y., and the concrete-encased s t e e l j o i s t s u p p o r t e d f o r m w o r k system is often referred to as a Melan Arch System. It was a seven-span, 660-ft-long, four-lane closed spandrel, earth-filled arch bridge with a roadway width of 42 ft and a 6.5-ft-wide sidewalk on both sides. It had become functionally and structurally deficient. Since Woolpert opened its business in Dayton the same year the original bridge was constructed, it seemed appropriate that Woolpert be involved in this bridge replacement 100 years later. The Replacement Bridge The new bridge is a 72-ft-wide, six- lane structure with two 10.5-ft–wide sidewalks (including rail system) for a total deck width of 93 ft. The bridge is set on a 6.7 degree skew with a tangent alignment. It is flanked by 30-ft-long approach slabs. There are constant grades over the first two and a half spans at each end and a short vertical crest curve over the middle 120 ft. T h e re p l a c e m e n t b r i d g e i n c l u d e s five 110-ft-long spans, measured from the centerline of piers, and two 55-ft-long spans at each end for a total bridge length of 660 ft. The longest superstructure elements consist of 42-in.- deep by 48-in.-wide adjacent precast concrete box beams, which span 84.5 ft between centers of bearings, with a 6-in.-thick cast-in-place concrete composite deck. End span box beams are 41.3 ft long. Architectural precast concrete fascia panels are supported from the exterior box beams by steel tube extensions from the backs of the panels to plates embedded in the top of the beams or in the deck. The panels are 6 ft 8 in. tall and 2 ft 7 in. wide. The locations of embedded plates were closely coordinated with barrier rail post locations and light pole supports, eliminating conflicts during construction. The choice of concrete as a design material resulted from the study to evaluate the final structure options, and is anticipated to match the durability of the 100-year-old concrete structure that was replaced. Over 1.5 million pounds of epoxy-coated reinforcement were used. To minimize future maintenance costs, semi-integral abutments were utilized and limited superstructure jointing was also incorporated. Community Involvement The project began with four technical group meetings where interested parties were invited to discuss the aesthetics, maintenance of traffic, and future traffic flow options. Several alternatives were presented, and in the end, the enhanced bridge replacement on the existing alignment option was chosen. E a c h o p t i o n p re s e n t e d i n c l u d e d preliminary drawings, renderings, and detailed descriptions of the upgrades, along with anticipated costs for each. The project's architect gave significant consideration to the complex setting and integral nature of the bridge's profile STEWART STREET BRIDGE / DAyTON, OHIO BRIDGE DESIGN ENGINEER: Woolpert Inc., Dayton, Ohio PuBLIC INvoLvEMENT CoNSuLTANT AND CoNCEPTuAL DESIGNER: T.y. Lin International, San Francisco, Calif. PRIME CoNTRACToR: Ahern and Associates Inc., Springfield, Ohio BoX BEAM PRECASTER: Prestress Services Industries LLC, Decatur, Ind., a PCI-certified producer SPANDREL PANEL PRECASTER: High Concrete Group LLC, Springboro, Ohio, a PCI-certified producer S oLID TIE BEAM PRECASTER: Ahern and Associates Inc., Springfield, Ohio by Mike Avellano, Woolpert Inc. Major Infrastructure Improvement in City of Dayton The schedule was accelerated to just 18 months. by Mike Avellano, Woolpert Inc. Replacement of the 14 | ASPIRE , Summer 2011 P R O J E C T Book_Sum11.indb 14 7/1/11 9:59 AM