Isleta Boulevard in the Albuquerque South Valley extends from Isleta Pueblo north to Bridge Boulevard, near downtown. This old, historic roadway was originally part of the Camino Real, or King's Highway, from the Spanish territorial days. In the 20th century, the route was designated as US-85 and was the primary north-south route through New Mexico prior to Interstate 25. Isleta Boulevard has served as a primary arterial for residents of the South Valley and as far south as Belen for decades and is bordered by fairly high-density population.
Wear and tear on the roadway over the years has led to various rehabilitation and maintenance projects. Because some of these projects were performed in emergency situations, there were few as-built drawings to document what was in place at the start of this major reconstruction.
On July 26, 2005, the Bernalillo County government received bids for reconstruction of Isleta Boulevard between Rio Bravo Boulevard on the south to Arenal Road on the north. While Bernalillo County was officially the owner, the project was a joint effort involving the city of Albuquerque, New Mexico Department of Transportation, Middle Rio Grande Conservancy District, and Albuquerque Metropolitan Flood Control Authority. Given the mixture of agency involvement and interaction, NMDOT standard specifications were used in combination with other agency specifications for certain project features such as underground utilities.
The $23,062,576.98 contract was awarded to Twin Mountain Construction (TMC) on Aug. 25, 2005, but the notice to proceed was delayed until Oct. 26 to allow for the relocation of existing utilities, primarily telephone and power lines. The original contract divided the project into three phases, with the first phase to be completed in 220 calendar days and phases two and three in 200 calendar days each.
The project's close proximity to the Rio Grande means very sandy soil and an underground water table very close to the surface. The area has been prone to flooding and had virtually no storm drainage facilities in place. It was quickly learned that groundwater elevations were extremely variable and unpredictable throughout the project limits. The groundwater presence was a recognized potential difficulty when the project was designed and bid specifications were written. Dewatering was necessary to place approximately 30,000 linear feet of gasket-sealed reinforced concrete pipe for storm drainage. The typical excavation for this pipe was an 8-foot depth. The dewatering was accomplished using both well points as well as dewatering wells.
These storm drainage pipes were designed to discharge into existing Middle Rio Grande Conservancy District irrigation supply ditches at five different locations. The elevations of the storm drainage discharge were lower than the ditches at three locations, however, necessitating the use of detention ponds to collect the water and pump stations to get the water into the ditches. All of these locations were west of Isleta Boulevard. The storm drainpipes were run down several side streets, resulting in additional street construction off of the Isleta Boulevard right of way.
Under the roadway was an existing 36-inch sanitary sewer interceptor line carrying sewage to the wastewater treatment plant south of Rio Bravo Boulevard and east of the river. This pipeline was deteriorated in several areas, so as part of this project, crews inserted an epoxy lining to help prevent further deterioration. Subcontractor Insituform performed this work. During the course of this work, numerous local services not shown on existing drawings were found to be connected to this pipe. Because the epoxy liner would close off these services, design plans called for the installation of approximately 6,600 linear feet of 8-inch sewer line to maintain services.
The right of way was generally narrow, with no curb and gutter or sidewalks. Project scope provided for the construction of these features along with bus lanes, bicycle lanes, wheelchair ramps, and two lighted crosswalks.
The biggest challenge on the project, according to David McClendon, project manager for Twin Mountain Construction, was unknown utility locations. Much of the project involved workmen using hand shovels digging around unknown obstacles and utilities. "The difficulties we encountered on Barcelona Road were the worst, but typical of unplanned utility challenges throughout the project. We had to be flexible every day."
The original project approach divided the job into three areas, with work to be completed in one area before continuing to the next area. To keep the project on schedule, when problems were identified in one area, it was necessary to move crews and equipment into other areas and continue working. As the challenges began to mount and the potential of falling behind schedule arose, Twin Mountain, Bernalillo County and the other agencies involved worked out a new plan that led to a more timely decision-making process and the eventual abandonment of the original three-phase schedule. Through these collaborative efforts and successful agency partnering, the project achieved substantial completion 50 days ahead of schedule.
The length of the project on Isleta Boulevard is only 1.85 miles of roadway, but the additional work required on 10 cross streets encompassed 2.47 miles, for a total of 4.32 miles of roadway rehabilitation. Storm drainage pipes were installed nearly the entire roadway length of the project. These lines, all reinforced concrete pipe, include 2,100 linear feet of 36-inch, 5,500 linear feet of 30-inch, 2,800 linear feet of 24-inch, and 3,400 linear feet of 12-inch to 18-inch. In addition, the project included precast concrete box culverts, laid in singles or doubles. The CBCs included 650 linear feet of 4-foot by 2-foot, 199 linear feet of 6-foot by 2-foot, 850 linear feet of 4-foot by 3-foot, and 1,590 linear feet of 5-foot by 3-foot.
The storm drainage upgrades were a major component of the project. The storm drains feed into five detention ponds, which required 52,900 cubic yards of excavation. Pump stations and 3,000 linear feet of force main piping were installed at three of the ponds where the elevation of the discharge pipes was lower than that of the pond.
The utility reconstruction required 3,200 linear feet of 6-inch water line realignment, 7,100 linear feet of 10-inch water line realignment, and 156 residential water connections. The sanitary sewer rehabilitation primarily consisted of 6,750 linear feet of 36-inch line, including cleaning, installation of epoxy liner and rehabilitation of 17 large diameter manholes. As mentioned above, there was approximately 6,600 linear feet of 8-inch line run parallel to the 36-inch interceptor to collect the 136 residential connections that would be blocked by the epoxy lining.
Roadway work for widening Isleta Boulevard from two lanes to three lanes with an auxiliary/turn lane was demanding under traffic. Work building curb and gutter, sidewalks, drive pads, etc., was extensive, as none were previously in place. In addition, the right of way was rather close to the existing buildings. Major quantities included 40,300 cubic yards of unclassified excavation; 96,700 square yards of subgrade preparation; 31,000 tons of 6-inch base course; 47,000 square yards of temporary detour paving; 47,000 linear feet of concrete curb and gutter; 4,000 square yards of drive pads; 7,400 square yards of sidewalk and wheelchair ramps; 19 bus stops; 3,000 square yards of colored or decoratively stamped concrete; and 250 square yards of concrete median paving.
The asphalt paving was in three categories: Side streets were paved in two lifts of 2 inches each for a total of 9,100 tons. The arterial pavement, mostly on Isleta Boulevard, required two lifts of 3-inch thickness for a total of 16,000 tons. In addition, there were 56,300 square yards of 5/8-inch-thick open-graded friction course.
The project also included signal rehabilitation of two intersections and installation of new signalization at four intersections.
The project was a team effort involving six major subcontractors, five of them based in the Albuquerque area:
- Insituform was the subcontractor for the rehabilitation of the existing 36-inch sanitary sewer interceptor.
- Valliant Construction installed curb, gutter and sidewalks.
- McDade-Woodcock was the electrical subcontractor, primarily involved with signalization.
- Heads-Up Landscaping was the landscape and irrigation subcontractor.
- J & D Contracting was the subcontractor for water and sewer connections.
- Valley Fence Co. was the fencing subcontractor.
The Isleta Boulevard rehabilitation project was not easy when compared to new construction through an undeveloped area. There was constant traffic flow, many utilities and other obstacles not shown on the plans. The dewatering was, as always, anything but predictable. Utilities had to be kept in service for homes and businesses. Twin Mountain Construction recognizes the efforts of all subcontractors, material suppliers, Public Service Co. of New Mexico (Gas and Electric divisions), Qwest, and Comcast for their part in successfully completing the project on schedule. It was truly a team effort.