Preserving Arlington Memorial Bridge

Two Bridge Spans Become One on Interstate 65 Over Alabama River

Fri March 02, 2007 - Southeast Edition
CEG



The state of Alabama has been experiencing strong statewide employment, new industry announcements and expansions as well as an overall healthy business investment climate.

As industry continues to expand in Alabama and as new residents arrive, the department of transportation has turned its attention to the quality of the transportation network throughout the state. The quality of a state’s roads, highways and bridges is an important factor in continuing economic growth and Alabama Department of Transportation (ALDOT) has allocated approximately $2 billion for road and bridge projects throughout the state. Interstate 65 has received some long neglected attention due to this state transportation renovation effort.

Interstate 65 not only provides interstate connections for Alabama residents but it is a main connector for the South with the Midwest, from the ports of the Gulf of Mexico to the ports of the Great Lakes. Commonly called Alabama’s main street, it begins in Mobile, Ala., and ends in Gary, Ind., serving many major cities along the way, including Montgomery, the capital of Alabama, with a population of more than 200,000 people.

Just north of Montgomery, Interstate 65 crosses the Alabama River. As traffic moves toward the river, the interstate becomes two bridges, one northbound and one southbound with three lanes in each direction. This portion of I-65 has been a site of heavy traffic congestion and as part of the state transportation renovation plan, ALDOT decided it needed to be upgraded. By closing the gap between these two bridges to make one wider bridge with multiple lanes on each side, traffic flow could increase and provide easier travel for people between Montgomery and Prattville.

The Alabama River bridge widening project was awarded to general contractor R.R. Dawson Bridge Co. of Bessemer, Ala. This project involves the removal of the existing bridge rails from the northbound and southbound lanes. As the bridge rails are completely removed, a new bridge deck is being constructed between the two existing ones to provide one wide and seamless bridge with northbound and southbound lanes.

The general contractor and ALDOT knew they needed a company with experience working with space constraints, limited access and the ability to reduce noise, dust and debris. In May 2006, ABC Cutting Contractors of Montgomery, Ala., won the bid for the removal of the existing 9-in. thick (23 cm) concrete bridge rails using diamond-cutting technology.

Operators began pre-cutting the bridge deck with a Core Cut, 61-hp (82.35 kW), Deutz turbo diesel flat saw, leaving 10 ft. (3 m) of bridge deck uncut every 50 ft. (15 m). The next step would be to cut the rails off the portions of the bridge over land. Cutting the rails off bridge sections over the river will be done later. When it originally bid the job, ABC believed that flat sawing would be the better cutting method for the bridge rails.

Company officials soon found out that the slab saws would not work because there was only 4 ft. (1.2 m) of space between the temporary barrier rails and the face of the curb. The decision was made to switch to wire sawing, but the crew had to devise a system to move the water, the core drill equipment and the wire saw along the bridge. By mounting a 50-gal. (189 L) water tank to the front of a lift jockey, it was able to attach a core drill rig to the side of the water tank. The lift jockey was then fitted with a hitch to pull the wire saw unit behind it like a mini-train as operators moved across the bridge.

Once the rails were pre-cut, ABC operators core drilled holes to run the wire. With the SB Hydrostress wire saw hooked onto the mini-train, they began cutting to divide the bridge rails into 50-ft. (15 m) long sections. Operators wire cut the rails, which were 4 ft. (1.2 m) high and approximately 9 in. (22.8 cm) thick. Ten ft. (3 m) of bridge deck was left uncut on each section to hold the bridge rails in place. When the cranes were in place, ABC operators went back with the flat saw to finish cutting the 10-ft. sections. As each section was cut, each 50-ft. long bridge rail section was released from the bridge. The crane holding it would then lower it to the ground.

There were numerous constraints that ABC operators had to contend with while on the job. With the limited amount of space they had to work in, ABC operators had to work close to the wire saw unit. It was necessary to put up a 4- by 8-ft. (1.2 by 2.4 m) protective wire screen between the operator and the wire saw unit. This would help to protect the workers from any potential flying hazards or if the diamond wire broke during cutting.

Getting water to this equipment also was an issue for ABC Cutting, but it found a creative solution by modifying the equipment so all equipment could be mounted on a mini-trailer system to be pulled along in the confined space between the bridge rail and the temporary traffic barriers.

ABC operators wore the necessary personal protective equipment during sawing and drilling and were tied off at all required times for fall protection. Heat also was a major issue for workers as temperatures soared into the 100s with high humidity and no shade. Workers were supplied with plenty of water and sports drinks to keep hydrated and took breaks when needed.

The Alabama River Bridge project is still underway for ABC Cutting Contractors. The total amount for the project is 4,908 lineal ft. (1,500 m).

“Despite the challenges this project brought, by working with the R. R. Dawson Bridge Co., we were able to overcome the obstacles,” said Ricky Drinkard, area manager.

Jason Hines was the senior operator for this project and helped with the coordination of the cutting on site. Dawson will be completing the new lanes before ABC returns to groove the new bridge deck at the end of this project.

ABC Cutting Contractors have been in business for 20 years. The company offers services in core drilling, slab sawing, hand sawing, wall sawing, wire sawing, slab grinding, concrete bursting, concrete crushing, diamond chain sawing, bridge and safety grooving and road and bridge grinding.

Reprinted courtesy of the Concrete Sawing & Drilling Association, “Concrete Openings” magazine, December 2006.