Main Street Bridge

Main Street Bridge

The Main Street Bridge carries Main Street over the Scioto River in Columbus, Ohio. It is the first single inclined arch suspension bridge in North America and the fifth in the world to use an inclined arch superstructure.


History

The original Main Street Bridge, a multiple-span, open-spandrel concrete deck arch bridge, was constructed in 1937. 3 It was designed by Edward A. Ramsey and built by J.H. Prior.

The crossing was closed to traffic in 2000 after it had substantially deteriorated and was demolished starting on August 25, 2006. 7

Replacement

After the Main Street Bridge had been closed to traffic, it was decided to replace the crossing rather than rehabilitate it due to cost considerations. The design criteria for the proposed new bridge was established by state and federal transportation officials, city leaders, the state historic preservation office, the Franklin County engineer, area residential and commercial developers that were near the bridge, the Greater Columbus Arts Council and the downtown association, among others. 3

After much public debate and discussion, the city of Columbus contracted with Dr. Spiro Pollalis, professor of design technology and management at the Harvard University Graduate School of Design to design a new crossing. 3 The city also hired DLZ Ohio, a Columbus-based architectural, engineering and environmental services company, for project management. DLZ was in charge of designing the substructure and railing, conducting geotechnical engineering, and designing the approach roadway. DLZ selected HNTB as a partner for the lead structural design work.

The original concept called for an inclined steel arch with a very shallow 10:1 span-to-rise ratio for the main arch, although it would have created significant axial and bending forces. 4 To accommodate those forces, high strength steel and concrete would be required. Because of the projected high cost, the crossing was revised to a 6.6:1 span-to-rise ratio with a 10° incline, which shortened the arch from 480 feet to 400 feet and saved 60,000 pounds of steel. The revised design also called for 13 I-struts to attach the arch to the bridge deck, while the initial design featured tapering geometries that would change depending on the strut, which would create 13 distinct structs that would need to be designed and tested separately.

The bridge proposal also featured two V-piers that were formed by the convergence of the main arch and secondary arches, but it was found to not be structurally feasible. 4 A crescent pier was instead added and the two flanking arches were removed.

The initial project cost in 2002 was $19.5 million for an inclined steel arch, although the estimate was derived from a firm that had wanted its particular company chosen for the contract. 5 By 2004, the cost estimate had risen to $29.2 million and $42 million by 2005. Financing for the new bridge would be derived from $15 million from the state’s Infrastructure Bank and $8.3 million in city bonds for the bridge design. 6

When construction bids were let in 2006, the lowest bid was $44.1 million. 5 The contract for construction was let shortly after. 1 By May 2009, the Main Street Bridge project had $2 million in construction cost overruns, which did not include $3 million in overruns for design costs and $4.5 million in inspection costs.

The new Main Street Bridge was completed at the cost of $60.1 million 2 on July 30, 2010. 1 It was the first single inclined arch suspension bridge in North America and the fifth in the world to use an inclined arch superstructure. 1


Gallery


Information

  • State: Ohio
  • Route: Main Street
  • Type: Inclined Arch Suspension
  • Status: Active - Automobile
  • Total Length: 638 feet (1937); 700 feet (2010)
  • Main Span Length: 109 feet (1937); 400 feet (2010)
  • Deck Width: 40 feet (1937); 53 feet (2010)

Sources

  1. “Main Street Bridge.” Downtown News Network. N.p., 2011. Web. 13 Mar. 2012. Article.
  2. “Main Street bridge opened to traffic.” Columbus Dispatch 30 July 2010: n. pag. Web. 13 Mar. 2012. Article.
  3. “Main Street Bridge.” Franklin County. N.p., n.d. Web. 13 Mar. 2012. Article.
  4. “The Main Street Replacement Bridge.” Rogowski, DeMond and O’Rork. Web. 13 Mar. 2012. Article.
  5. “NBC 4 Digs Into Over-Budget Main Street Bridge.” NBC4I. N.p., 20 May 2009. Web. 13 Mar. 2012. Article.
  6. “Landmark Opening.” Columbus Dispatch 30 July 2010: n. pag. Web. 13 Mar. 2012. Article.
  7. “Washington Blvd. closing for bridge demolition.” Columbus Dispatch 24 Aug. 2006: n. pag. Web. 13 Mar. 2012.

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