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/395356
PROJECT SPANNING the Wolf River Wetlands in Tennessee by Tim Huff, Tennessee Department of Transportation As part of the proposed transportation improvements in southwest Tennessee, the Tennessee Department of Transportation completed plans for a new highway between existing State Routes 193 and 196 in Fayette and Shelby counties. The SR 385 (also known as I-269) project originally consisted of nine bridges. Bridge No. 3, with a length of 720 ft, crossed the Wolf River. Bridge No. 4, with a length of 177 ft, crossed a Wolf River tributary. The original concept for these two Wolf River bridges used precast, prestressed concrete girders on cast-in-place concrete columns with pile caps. Given the extreme depth of the soil profile in this area of the Mississippi embayment, concrete friction piles would typically be used for such a concept. Environmental concerns, which identified the surrounding area as wetlands, necessitated a change in the plans for Bridge Nos. 3 and 4. It would not be possible to fill in the wetlands between the two bridges and the entire area would need to be bridged. The two structures were combined and lengthened to become dual, 3250-ft-long structures, each comprised of 33 spans in four continuous units with pile bent substructures. Double bents were provided at the adjacent ends of each unit. Approximately half of each structure lies in a horizontal curve having a 2865-ft radius with the other half in a tangent section. PROFILE STATE ROUTE 385 OVER THE WOLF RIVER / FAYETTE AND SHELBY COUNTIES, TENN. BRIDGE DESIGN ENGINEER: Tennessee Department of Transportation, Nashville, Tenn. CONSTRUCTION ENGINEERING INSPECTION: Allen and Hoshall, Memphis, Tenn. PRIME CONTRACTOR: Hill Brothers Construction Company, Memphis, Tenn. PRECASTERS: Prestress Services Industries of Tennessee, Memphis, Tenn.—a PCI-certified producer (girders) and Construction Products Inc. of Tennessee, Jackson, Tenn.—a PCI-certified producer (deck panels) BRIDGE DESCRIPTION: Dual, 33-span, 3250-ft long, precast, prestressed concrete bulb-tee girder bridges. STRUCTURAL COMPONENTS: Three hundred and thirty 54-in.-deep, bulb-tee girders (31,941 ft); 3384 3½-in.-thick, precast, prestressed concrete deck panels with 4.75-in.-thick cast-in-place concrete deck; and cast-in-place concrete pier caps, pipe-pile-bents, and integral abutments. BRIDGE CONSTRUCTION COST: $14,220,000 ($50/ft sq.)