Brownville Missouri Bridge Work Resumes for 2010
Work on the Missouri River Bridge at Brownville began last September, with Cramer & Associates, Inc., of Grimes, Iowa, hired as the project contractor. Money for the project has been funded through the American Recovery and Reinvestment Act. The project is expected to cost $8,113,822.82.
Planned project improvements on the bridge are to include a new deck, new railing, repair of the sub-structure and new paint. The project is to take two years to complete.
Update of Last Year’s Work
The contractor began the strengthening of the steel girders that support the roadway. This stage of operation had to be completed after the old concrete deck was removed above the steel, and once there was no traffic on the bridge.
The strengthening was performed during the weekend closures and included removal of the existing outer plates, cleaning the rust from the remaining plate, painting to prevent future rust, mounting the new steel plate.
Holes had to be drilled in the new plate on the project and were bolted to the new plates once drilling was complete. Work was performed 24 hours per day during the weekend closures.
Last year, the contractor scheduled two weekend closures of the bridge to work on the strengthening operations while no traffic was on the bridge. At the end of 2009, the contractor reported that 43 percent of the strengthening operations were completed.
According to the contractor’s schedule, the next anticipated weekend closure is for late April. Three more closures will be necessary in July and August to complete the strengthening operations. Work will be performed on the first two bridge sections on the Nebraska side in April.
Early 2010 Work
Work shut down on the bridge in the middle of December due to winter weather and resumed in early February. Work is currently being performed on the following:
• Forming the bridge deck on the east spans. The new concrete deck is anticipated to be poured in March or April on the units east of the truss.
• Removal of the old concrete deck on the truss and west approaches.
• Completing steel repairs below the bridge deck from under the bridge.
The current schedule shows completing the north side construction in July and switching traffic to the north side soon after. All necessary materials have been purchased, so there should be no need to wait for materials.
Traffic Signal Timing
The traffic signals on the project work by detecting vehicles over loop detectors in the pavement. The loops detect a vehicle above them and change the light to green when the opposing traffic has passed over the bridge. If there is no detection within five seconds, the light then cycles to yellow and red. Traffic is allowed approximately two minutes to clear the bridge. This is equivalent to a vehicle traveling just over 15 miles per hour. The timing is set for slower moving trucks to be able to cross before the light turns green in the other direction. A vehicle traveling 30 mph will clear the bridge in half the time, or one minute.