(Demo) Road and Bridges May 2010 : Page 27

expected to start the first week of May. When the 400-ft arch span is ready to be connected, it will probably be transported by a couple of barges. The end floor beams of the arch will be used as part of the lifting apparatus. The tied arch is a basket handle, and the rims will incline toward the center of the deck. The arch rib is actually “eye-shaped,” and a criss-crossing network hanger arrangement will be used. The deck will contain cables—a total of 64, 32 on each side—and floor beams at a 12-ft spacing. “The cables generally cross more than once,” said Zoli. “They should cross twice in most circumstances.” Three of the water piers will use float- ed-in coffer dam-type construction, with the remaining three using conventional coffer dam sheeting, tremie seal-type construction. One spread footing will be on the shoreline and two abutments will be on micro piles to minimize envi- ronmental impacts. All of the piers—a total of seven—will be constructed with conventionally reinforced concrete, and drilled shafts 6 ft in diameter will be inserted as deep as 100 ft into rock. A total of six drilled shafts will be used for the main piers and four will be used for the approach piers. A couple of safeguarding measures— granite and inclined facing—have been designed to protect the piers and foun- dations from the lake’s punishing ice. No longer worth the gamble The Cline Avenue Bridge (S.R. 912) in East Chicago, Ind., became permanently disabled on Nov. 13. That is when the Indiana Department of Transportation (INDOT) closed the structure due to an ongoing case of severe and rapid cor- rosion. INDOT revealed the following about the extent of the disease: • Several steel rods holding together the individual bridge sections had failed completely due to corrosion, and other tension rods were deteriorating rapidly due to accelerated corrosion; • Corrosion was occurring inside the walls of the concrete girders below the bridge deck, and those girders were cracking; • New cracks were developing on an Nevada span gets the attention of Congress The Galena Creek Bridge in Reno, Nev., consists of a supporting cathedral arch, and at 1,700 ft long will be the largest structure of its kind in the world. In late March, it received the attention like no other bridge in the U.S. when Rep. Jim Oberstar (D-Minn.), chairman of the House Transportation & Infrastructure Committee, and Rep. Peter DeFazio (D-Ore.), chairman of the Subcommittee on Highways and Transit, told the inspector general to go in for a closer look. Calvin Scovel III was supposed to give some attention to a 30-ft crack in one of the concrete box girders supporting the concrete deck. According to Nevada DOT spokesperson Scott Magruder, the crack occurred when crews were performing high-pressure air testing in the ducts, which were used for post-tensioning and will later be filled with grout. “They actually heard it when they were doing testing,” Magruder told ROADS & BRIDGES. “They knew right when it happened that it was not a good situation.” Magruder said a number of steel plates will be bolted onto the damaged sec- tion at a cost of about $900,000. The Galena Creek Bridge is part of the $400 million I-580 freeway extension, which is an 8.5-mile road project that includes the construction of nine bridges. The structure, which consists of two spans, is expected to be complete in late 2011. The Congressional attention actually was the result of a claim from a former worker with prime contractor C.C. Myers following work on the Galena Forest Bridge. There, the worker claimed he was told to apply substandard material. Ac- cording to Magruder, the worker was using a patching material to fill in voids in the concrete after forms were removed. “It was purely cosmetic,” he said. “We welcome the inspection. We want to make sure we are doing the right kind of fix, so to get another opinion would be good.” accelerated basis. Over 300 new cracks were discovered during the bridge’s last inspection; and • Cracks were developing along canti- levered sections of the bridge and on the bridge columns. As recently as spring 2009, pier 7 of the Cline Avenue Bridge required emer- gency repairs and temporary structural steel support. More extensive rehab was conducted a few months earlier, in December 2008, after the upper portions of concrete piers supporting the elevated roadway, which carries six lanes of traffic and two shoulders, had suffered significant cor- rosion, and INDOT engineers concluded that the top 10 ft of the damaged piers would have to be removed and replaced. Removing the tops of the piers required temporary support for the three concrete box girders carrying the roadway. Contractor JCI Bridge Group erected a dozen temporary steel piers in clusters of four, braced and tied together, under each of the three box girders. “The piers were fabricated from ⁄8 30-in.-diam., 7 -in.-wall steel pipe, filled with sand” said Carl Tungate, P.E., of JCI. “The 54-ft-tall piers sat on sill beams on the old footers.” ROADSBRIDGES.com 27

Campbell Scientific Inc.

 

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