In a dirt field just west of downtown Fort Worth, a giant gantry crane is being used to hoist freshly cured concrete and steel arches into an upright position.Here, the pieces of what many believe will be a new signature feature of Fort Worth's skyline -- the new West Seventh Street bridge -- are being cast.The arches each weigh 300 tons and stand 24 feet tall. Seven arches are completed, and five more are soon to be poured. Then, beginning in a little more than two months from now, they will be slowly fitted together to form the signature feature of a new West Seventh Street bridge spanning the Clear Fork of the Trinity River, connecting downtown to the Cultural District.The new West Seventh Street bridge project is one of the most unusual endeavors ever undertaken by the Texas Department of Transportation's Fort Worth district, officials said. More than half the work on the $25.9 million job is being done off-site to minimize the impact on traffic.At the conclusion of the Stock Show in February, crews are scheduled to begin the complicated task of moving each 300-ton arch for the bridge from the dirt field to the river -- a length of about five football fields. They'll close West Seventh Street to traffic during the night, and use special, multi-axle vehicles to slowly roll the arches into place.Officials say that when it's completed the new West Seventh Street bridge, which features stainless steel webbing and recessed lighting inside the arches, will redefine the city's image with a bold display that is a hybrid of public works and public art."This community is going to be really proud of that bridge," said William "Bill" Meadows of Fort Worth, a Texas Transportation Commission member. "Not only are people going to be amazed by the aesthetic quality of it, but we're delivering this infrastructure within budget constraints and with minimal impact on traffic."Like a shipyardThe contractor, Sundt Construction Inc. of San Antonio, is casting each of the 12 giant arches in a dirt field leased from Chesapeake Energy. Their work on the vacant property just east of the Target store and Montgomery Plaza is visible to passersby in the fledgling West Seventh neighborhood.Activity at the work site resembles that of a shipyard. Seven of the arches are complete, and the concrete for the eighth piece is scheduled to be poured today.Once the concrete is poured, it takes about four days for each arch to dry and about 14 days to cure. Then each arch -- a giant bow-shaped structure with stainless steel webbing -- is lifted from a horizontal to a vertical position using a three-story-tall gantry crane, which creeks and groans as it slowly rotates 300-ton pieces upright.The work is purposefully slow, as workers take care not to place too much strain on the freshly dried cast."If we rotate them too quickly, they may crack," said Ricardo Gonzalez, Texas Department of Transportation area engineer.Traffic impactBusiness owners in the West Seventh neighborhood -- which has become a very popular dining, shopping and residential area -- weren't looking forward to the bridge project when they learned about it several years ago.They worried that closing the bridge, which is used by about 12,000 vehicles per day, for any length of time would obviously cut off access to their properties.But, merchants, professionals and residents of the area couldn't have asked for a better timetable than the one laid out by the city and state transportation department for the next year or so, said Phillip Poole, a West Side architect."It's a beautiful solution," said Poole, who is also a board member of the Cultural District Alliance, which represents businesses along the corridor. "It's an amazing way to build a bridge and phase it in."The crux of the traffic plan is to get all the lane closures out of the way after the Fort Worth Stock Show & Rodeo, which concludes Feb. 9, and before Thanksgiving and the beginning of the 2013 holiday shopping season.Between February and roughly July, the bridge will be reduced to one lane in each direction, as workers remove overhangs, erect columns and move the new arches into place. The arches will be moved on special multi-axle vehicles that will slowly roll down West Seventh Street, much like how a museum recently moved the space shuttle Endeavor through the streets of Los Angeles.Between July and mid-November, the West Seventh Street bridge will be shut down to all traffic. The contractor has agreed to cut off traffic for no more than 150 days, and during that time detours will be posted to West Lancaster Avenue, transportation department spokesman Val Lopez said. Some motorists may also be directed to White Settlement Road.The old bridge will be demolished, and new floor beams and panels will be set into place. A new bridge slab will be completed.The new bridge will be painted white, and will feature recessed lighting that will make its arches visible for miles. Pedestrians and cyclists will be able to use a path on the outside of the arches, without mingling with automobile traffic on the inside of the arches.The bridge will also feature specially designed supports that make it possible for railroad tracks to be added, if the city wishes to later extend streetcars or other rail-based transit between downtown and the cultural district.The new bridge is scheduled to open to traffic in mid-November, although final work underneath the bridge will continue through January 2014.The new bridge will replace a 100-year-old structure that is quickly decaying to the point that it could eventually be deemed unsafe for automobile travel. The concrete is flaking, its rebar is exposed, and state inspectors for several years have declared the bridge structurally deficient, a Star-Telegram review from earlier this year concluded.Gordon Dickson, 817-390-7796Twitter: @gdickson
Seventh Street Bridge
Estimated cost: $25.9 million
Details: 12 concrete arches, each 24 feet tall and 160 feet long will run the length of the bridge (six per side).
Completion: Before Thanksgiving 2013
Sources: City of Fort Worth, Sundt Construction