BC Bridge project spans past and the future
The Cow Bayou Swing Bridge will soon be receiving a makeover. The bridge was opened in 1941 and will be totally refurbished, according to Paul Smith, a Texas Department of Transportation environmental specialist. Refurbishing the bridge will cost $2 million dollars versus spending $15 million to build a new bridge.
Smith said the bridge rehabilitation project has been in the works for several years, especially since it received some damage from Hurricane Ike. He added they are in the second part of a twofold project.
“Phase I has already been done, pre-Ike in 2007. We replaced the armor joints on the south side of the bridge so it could swing freely because it was binding at the joint,” Smith said. “Phase II will rehabilitate the remainder of the structure.
“After Ike came in, there was a survey of the damages completed. It will be completely refurbished. It will essentially be a brand new bridge.”
Basically, Smith said the mechanics are in good condition and the bridge will open much more efficiently.
“You’ll be able to flip a switch, the crossing arms go down, the traffic stops and the bridge swings open,” he said.
Construction is scheduled to begin in May 2013 and may last a year or two.
Southbound traffic on the taller bridge adjacent to the swing bridge will be converted into a two-way traffic pattern in both direction, southbound and northbound. Portable traffic barriers will separate traffic lanes.
The lanes will be narrow with no room for shoulders, though both lanes will be 11-feet wide.
“It will be an inconvenience to some folks who aren’t used to this. It’s now a four-land road and we want to keep the capacity as is. Drivers need to be careful and pay attention. We’re concerned for not only the safety of the traveling public, but also for the safety of the construction workers. This is temporary,” Smith said.
He added maybe some of the work could be done during non peak traffic hours and the last thing wanted is to create a big detour for drivers.
Smith said the one year delayed start will give TxDOT additional time to obtain the required permits from the U.S. Army Corps of Engineers and the U.S. Coast Guard. No clearance heights will be changing during the project. TxDOT coordinates with the coast guard to keep them informed.
After completion, boats will be able to move more easily on the bayou because the bridge will open fairly quickly. Environmental issues should not be a huge concern for the project. A more important issue is the fact that the Cow Bayou Swing Bridge is designated a historical bridge.
“We have to be careful with it. We had to go through the historical commission (Bridge City Citizens for Historic Preservation). We had to buy them off on the project. It’s non issues on the environment,” Smith said.
The scope of work according to TxDOT will include:
The federally assisted project will rehabilitate swing bridge over Cow Bayou in Bridge City. This project will be undertaken without the purchase of additional right-of-way.
Although its machinery and electrical components were partially submerged during Hurricane Ike in 2008, the bridge continues to carry northbound traffic along the state highway. While emergency repairs were undertaken after the hurricane, the bridge’s swing span, which is still operable, does not function on a regular basis.
As one of two center-bearing swing bridges in Texas, the National Register nomination completed in 2010 also found the structure to be significant under criterion c, engineering at the state level of significance. The bridge maintains integrity of design, material, location, feeling and association. Its integrity of setting is compromised due to the 1972 construction of the adjacent high-rise concrete bridge that carries southbound traffic on SH 87.
Proposed Scope of Work
The proposed project involves the rehabilitation of the swing bridge structure and its associated approaches, pedestrian walkway, embankments, boat fender system and bridge control house. Also included is the repair, replacement, or restoration of electrical and mechanical components, as well as the installation of traffic safety systems.
Replacement of the swing span concrete deck is the preferred option to patching, as large-scale concrete repairs tend to fail, even when performed with excellent craftsmanship.
Replacement is also better for the structure’s long term preservation, as deck removal will provide access to undertake substantive cleaning and repairs of the corroded steel structure below. As opposed to the existing deck with joints that allow for the seepage of water, the new deck will be continuous, making it stiffer and less susceptible to cracking and water penetration and stronger to carry larger loads.
The new concrete deck will include a new structurally integrated curb of the same height and dimensions.
Concrete abutments will be partially removed, rebuilt, cracks repaired and stoned rip rap laid at their base. Along the approach slabs and northbound lanes beyond the bridge, a four to six foot wide concrete sidewalk will be built.
A T 221 rail will border the slabs and a metal beam guard fence will provide safety along the lanes beyond. Spalling at the bents will be repaired. Steel I-beam approach span concrete deck will also be replaced.
Removal of the existing concrete deck will allow for appropriate interventions to address structural steel corrosion. New plates will be added to ensure added strength and durability of the structure. Riveted steel connections will be required within-kind replacements.
The original, custom-designed traffic rail will be replace din-kind with the concrete posts recast and the historic steel horizontal channels reused. In order to meet current crash test standards and to protect the outer rail, a new low-profile steel safety rail will be incorporated flush along the edge of the new concrete curb.
The 1972 non-ADA compliant walkway will be removed and replaced in similar materials and configuration.
Compliant steel grating and a wire-mesh rail that is similar to one from the same time period will be installed. Existing steel supports will be reused and the walkway will be bolted to the steel structure.
The lead-based paint will be removed. As there is no documented original paint color, a semi-gloss version of the current color will be specified in light gray.
The control house will be rebuilt to the same height and dimensions as the historic to better withstand hurricane force winds. In the exterior, asbestos panels will be replaced with hardie-plank panels replicating the same joint pattern and dimensions. New door and windows replicating the existing will be installed with hurricane wind resistant glass. The current exterior rail and metal grating will be reused. Inside, the original control desk will be rebuilt.
The currently rusted channel fenders installed in 1972 to protect the concrete piers will be replaced with similar ones in metal.
Mostly hidden form public view, the machinery controlling the swing mechanism will be degreased, cleaned, lubricated and calibrated to specified tolerances.
New components will be installed, such as link arms, bearing house assembly and actuator.
In general, electrical work includes replacement of conduit, safety switches, junction boxes and new submarine cable, which supplies power to the swing mechanism from the land side.
The proposed repairs and replacement materials will complement, as opposed to visually intrude upon the bridge. They will strengthen its structural and operational integrity, insure its future durability, and enhance the safety of vehicular traffic.
As a result, it is determined the proposed rehabilitation work will have no adverse effect to the historic bridge.
Smith said this project is very important because the swing bridge is how the name of the city changed from Prairie View to Bridge City.
“Local folks are very interested that it be done. We want to be sensitive to the local community’s interests. After this refurbishing, this bridge may last another 100 years. It’s a very sound structure,” he said.
Leslie Barras, a consulting party with Bridge City Citizens for Historic Preservation and an attorney who specializes in historic preservation law, said though the bridge is not structurally unsound, the rehab will give the bridge a new lease on life.
“It was the first bridge in Prairie View to cross a navigable waterway. There’s only one older in the area to survive (the Deweyville Swing Bridge opened in 1936). They’re rare in Texas. I love that bridge (the Cow Bayou Swing Bridge),” Barras said.
She also credited fellow consulting party, Mark Dunn, with saving the bridge.
“He had the vision and the passion. If it wasn’t for him, the bridge would be in the river now. He did all the heavy lifting. May part was minor,” she said.