A Caterpillar skid steer paired with a set of attachments, a trailer and a truck allowed the operator to efficiently travel around the jobsite and prepare the trench for the guide wires with minimal labor required.
This trench runs under the light rail tracks and contains the wiring between the stations.
The jobsite was very crowded and traffic had to be maintained while the work was being completed.
The finished light rail project required that everything between the storefront on one side of the street to the storefront on the other side of the street be reconstructed.
A side tip bucket on the wheel loaders made it possible to place bedding in trenches while operating in very confined spaces.
The light rail system in downtown Phoenix, AZ, includes a 20-mile starter line that will feature electric-powered light rail cars traveling at the posted speed limit for the road. The rail, overhead power lines and stations will all be carved out of the existing infrastructure.
This initial 20-mile line is broken up into five segments. Archer Western Contractors was awarded and completed Line Section 3.
Archer Western Contractors is a subsidiary of The Walsh Group, a firm currently ranked among the nation?s top 20 contractors. The company takes pride in the fact that, since it was established in 1983, it has never failed to complete a contract. The company has invested over $300 million in capital equipment and regularly employs over 1,000 engineers and skilled tradesmen.
Although it was no stranger to projects of this magnitude, this was the largest project ever handled by Archer Western?s Phoenix office, which had traditionally worked on waste water facilities.
?Our notice to proceed was May 16, 2005,? says Bob Fouty, project manager. ?The original bid contract was a little south of $95 million. With change orders, I think we are now at $102 million. We set a goal at the outset of the project to have all of the track down by November of 2007, and all of the station foundations complete.? This goal was accomplished.
Sizing up the site
The project presented a number of unique challenges.
?Although this is essentially a light rail project, we had to reconstruct virtually all of the underground utilities,? Fouty notes. ?[This included] sanitary, water, storm and electrical, new traffic signal features, new street lights, a lot of third-party utility relocations - Southwest gas, fiber-optic companies. Probably 60% of this job you don?t even see. It is all underground. We do all of the utility work ourselves, except for the third-party utilities.?
The shear size and uncertainties proved daunting. ?The as-built information, especially in the older parts of town, was virtually nonexistent,? Fouty recalls. ?If it ever did exist, it is long since gone. We found basements of buildings that had been torn down 40 or 50 years ago. They only tore down everything from the street level up; all of the subterranean features were still there. We found old coal chutes, tunnels, all kinds of things.?
Bidding a job with this many variables is difficult. ?That?s what experience is about,? says Fouty. ?It has been a very good partnership between ourselves, Valley Metro Rail and the City of Phoenix. The owner has been very good about recognizing those as unforeseen conditions. We have dealt with that fairly and equitably. You find an underground tunnel where you didn?t expect one and everything you have to construct over it now has to change.?
Archer Western also had to contend with crowded conditions. ?A lot of the work is intricate,? says Fouty. ?It is tight quarters and working around a lot of features, working up against existing buildings or canopies and overhanging traffic signal features.?
Fortunately, the contractor has plenty of equipment to choose from. ?We are an equipment intensive company,? says Fouty. ?We had a pretty big fleet of equipment here. We probably had 20 rubber-tired [backhoes] and four wheeled excavators. At peak, we had three track excavators.
?Because we are working in a lot of vehicle and pedestrian traffic, the equipment is a little smaller than normal,? he continues. ?We have to be able to get around the city streets. Virtually everything we have is on rubber tires. We have nine miles of city right-of-way. Just getting equipment from one location to another - if it?s not on rubber - is problematic.?
The multi-faceted project required crews to simultaneously perform several different tasks. ?At one point, we had every part of the right-of-way open,? says Fouty. ?Some of it was under utility relocation, some of it was under-track installation and some of it was paving curb and
gutter and sidewalk.
?We did a lot of shift work,? he adds. ?We also did a lot of weekend work. Our peak was about 48,000 man hours a month.?
Skid steers earn their keep
Anything that could help reduce manual labor and increase efficiency proved a benefit on the project. This is where the company?s Caterpillar skid-steer loaders came into play.
Archer Western had to go in and raise each of the manholes in the nine-mile right-of-way. This task was greatly simplified by mounting a drum coring attachment on the skid steers. ?We had the drums made for the skid steers to deal with the manholes,? notes Erik Holtz at Archer Western.
The drum is wider than a conventional model. ?With the wider drum, you can come back in and lay concrete around the manhole ring itself,? says Fouty. ?It is a lot better than jackhammering it out. It is cleaner and faster, and you are using your equipment instead of having it sit there and doing manual labor.?
The contractor also purchased a ?pecker? attachment, which was used in place of a jack hammer and hand labor for removing concrete.
Then there was the installation of the communication, traffic and electrification system backbone, which runs under roughly every foot of track. By putting together a skid-steer system complete with a trailer, truck and the necessary attachments, milling the pavement and digging the necessary trench practically became a one-man operation.
The key was to find the most efficient system. ?We decided what we wanted to do and we looked around,? says Fouty. ?We looked at three types [of skid-steer systems], then chose the Caterpillar. The thing I liked the best about them was all of the components were actually built by Caterpillar, as well. Some of the other makes, they provided pieces from somebody else. It is all great when everything works. But when it doesn?t, you want to be able to go to one place and get it fixed.?
Getting around in tight quarters
Besides the skid steers and attachments, Archer Western used other solutions to increase productivity on the crowded jobsite. One was the use of quick couplers on its Volvo wheel loaders. ?All of our loaders have the quick change for the tools,? says Fouty.
An L45 Volvo loader was equipped with a side tip bucket, as well as a front tip bucket. ?The side tip bucket allows you to work in tight areas,? says Fouty. ?You can come along parallel to the ditch and dump material into it because the bucket actually tips sideways. You don?t have to get perpendicular to the ditch.?
Two National Crane boom trucks also proved valuable on the congested jobsite. ?We used them for running materials around - manhole sections, pieces of pipe,? says Fouty. ?They have been real workhorses. We had them working both shifts. There are 12-ton cranes on them and the trucks are set up with both front and rear stabilizers. We had traffic control devices. We were moving steel plates for road crossings - hundreds and hundreds of steel plates.?
Finally, Archer Western custom fabricated people bridges to provide access across the guideway or the excavations for the guideway. These accommodations were necessary due to the volume of pedestrian traffic in the area.
?We had an area down here in front of U.S. Air Arena and Chase Field, [where] we had baseball games and basketball games on the same night,? Fouty notes. ?We had upwards of 70,000 people walking through our work zone. We worked pretty cooperatively with the City of Phoenix police department and traffic control systems to try to make sure our traffic control devices were where they were supposed to be and maintained.?
Through the use of the right tools and attachments, a partnership with the project designers and owners and the use of innovative approaches, Archer Western achieved successful on-time completion of the project.