Pueblo’s northern gateway is getting a $20-million facelift. And what a facelift it will be — a stunning urban interchange designed to look like a steel bridge from afar with sunshine motifs and extensive landscaping. It’s a far cry from what’s being dismantled and hauled away.
The construction project, overseen by the Colorado Department of Transportation (CDOT) and designed by engineering firm CH2Mhill, Denver, CO, is replacing the outdated and dangerous intersection at I-25, U.S. 50 and Colorado 47. It’s a busy intersection with restaurants, hotels and retail stores on both sides.
Monuments at both ends of the new bridge stand 26.25 ft. (8 m) above the pavement and are 6.56 ft. (2 m) wide. “It looks like a sunburst,” said David Miller, resident engineer of CDOT. Miller added that the concrete girders will be scored to look like a steel bridge from a distance. “We’re trying to make it pedestrian friendly. It will have walks underneath since there are a lot of businesses on both sides and restaurants and motels on one side. We want to make people feel safe to walk from one side of the interstate to the other. With the current bridge, you couldn’t do that. This one is real open, real airy and more pedestrian friendly.”
The new interchange is the last of four construction phases at the location. The first three focused on alleviating traffic woes on the state highways running east and west under the interstate. The frontage road was realigned away from the I-25 interchange, a couple of roads were dead-ended with cul-de-sacs and retention ponds were added to help with 100-year floods.
Construction on the new interchange began in mid-March and is expected to be completed by November 2001. The single-span urban interchange will be 367.45 ft. (112 m) long and supported by two outside spans. PCL Constructors, Denver, CO, is the contractor for the job and has a continually growing list that includes 33 subcontractors and suppliers. PCL, the U.S. subsidiary of Edmonton, Canada-based PCL Constructors Inc., also was the contractor for the Colorado 47 phase of the project.
The interstate is being raised 16.4 ft. (5 m) to satisfy drainage, sight distance requirements and the bridge, which accommodates two lanes of traffic on each side at the moment, and will ultimately accommodate three lanes of traffic in each direction. “We just don’t want to build a bridge and then have to build a bigger one,” said Miller.
The bridge is being built in two parts. A temporary bridge for northbound traffic was constructed with southbound traffic moved to the original northbound lanes. Norsar, Denver, CO, demolished the southbound portion of the bridge in two nights. All of the concrete was taken down on the first night and the remaining steel girders were removed the following night. All four traffic lanes will move to the new southbound lanes to allow removal of the temporary bridge and northbound lanes.
“Any time you build a big span, it creates its own challenges. We’ve done this type of construction, but not in this area,” Miller said. Though construction of the new bridge is interesting in and of itself, it’s what’s happening north of the interchange that is drawing the most attention. Grimm Construction of Louviers, just south of Denver, CO, is boring a tunnel under I-25 to make room for 72-in (182.88 cm) Hobas pipe. Hobas pipe is made of silica sand and resin and coated inside and out with fiberglass. It’s the first time Hobas pipe has been used in Colorado.
Grimm Construction leased a 10-ton (9 t) tunnel-boring machine (TBM) from Akkerman Tunneling Equipment, Minneapolis, MN. They will drill three bores 15-ft. (4.57 m) deep for the jack frame, which will hold the boring machine and the “muck car.”
Steve Johnson, project manager of Grimm, said the job should take two to three months, depending on soil conditions. “We could put in 30 or 40 ft. (9.14 or 12.19 m) of pipe a day,” said Johnson.
The front of the boring machine is a rotating cutter, with red carbide teeth to make a bore about an inch larger than the pipe. An operator sits inside the TBM and steers it with the help of a remote laser that targets the line and grade for the bore. Excavated dirt goes by conveyor over the TBM and into the muck car behind it. The muck car, driven by an operator, rides out on temporary rails. A 65-ft. (19.81 m) crane empties the skip, which can hold 3 to 3.5 yds. (2.74 to 3.2 m) of dirt. The pipe is then rammed into position and the cycle is repeated.
The 70.86 in. (180 cm) Hobas pipe accounts for half of all of the pipe that will be laid as part of the project. Other pipe will range in size with the smallest measuring 14.76 in. (37.5 cm). The project calls for 196,850 sq. ft. (60,000 sq m) of concrete pavement; 5,500 tons (5,000 t) of asphalt; 542 tons (487.8 t) of regular and epoxy-coated steel; and requires 410,104 cu. ft. (125,000 cu m) of fill dirt. The original plan was to haul the fill dirt in from another site, but it turned out that dirt from the new retention pond/park south of 29th Street more than met requirements and 291,994 cu. ft. (89,000 cu m) was excavated. It will be replaced with the same amount of less desirable dirt.
Miller said that instead of putting up a noise wall, it was deemed a wiser use of funds to purchase 35 homes south of 29th Street and turn the area into the retention pond and park. Basement flooding was a recurring nightmare for homeowners in the area, he added. Now rainwater will fill the basin and empty within six to eight hours through existing 24- to 48-in. (60.96 to 121.92 cm) pipes under the interstate and Pueblo residents and travelers have a new place to enjoy picnics and time outdoors.
Miller said, “We could have built the noise wall, but we still would have had a drainage problem. Now we’re beautifying the area. And we’re solving a safety problem because it didn’t have a guard rail.”
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