Retaining walls help reinforce busy New Mexico interstate
The Paseo Del Norte/Interstate 25 interchange is one of the busiest corridors in New Mexico, and there was a major issue with traffic congestion during the morning and afternoon rush hours. This road is one of the main access points to Albuquerque, and the city needed a solution that would make it easier and safer to travel on the highways.
The daily freeze/thaw cycles of New Mexico’s climate, as well as a narrow workspace along a highly active interchange, created unique challenges for the Paseo Del Norte/I-25 interchange Department of Transportation project.
The retaining wall texture was chosen to complement New Mexico's aesthetic.
Reducing traffic congestion due to right-of-way limitations, creating an Americans with Disabilities Act (ADA) accessible pedestrian walkway and bike trail system, and improving air quality and safety were priorities, and several retaining walls were required to make the project possible.
Given only 18 months from design to build, the construction process was on a time crunch. It was necessary to choose a product that could be installed quickly.
“We needed something that was quick, easy, maintenance-free ... and something that the contractor could come in and place periodically because there were also some utilities that were back and behind [the wall],” said Sean Melville, P.E., design engineer for Bohannan Huston.
Construction also was taking place along a private property line that limited construction space and access to the utilities, so using a modular product that could be installed in phases as the project progressed was key.
“We had a lot to build, and had a very short time frame to build it. And we had to have solutions that were flexible and cost-effective on a design-build project. And Redi-Rock was one of those products,” Melville said.
An ADA-accessible walkway and bike path help manage the flow of the Albuquerque trail system.
Redi-Rock has been used in highway, bridge and erosion control projects around the world. The gravity or reinforced options, along with several setback options, make it possible to design walls to solve almost any challenge.
“It allows some flexibility to our designs. It really gives you the opportunity to utilize a system that is quicker to install so the phase of construction is easier,” Melville said.
The 1-ton blocks used in the gravity wall system can build tall retaining walls without reinforcement in many applications. This makes it easier to build close to property lines while minimizing excavation and installation costs and allowing for projects to be finished at an accelerated rate.
For the taller walls on the I-25 project, geogrid reinforcement was included in the engineering designs for added stabilization. Where reinforcement is necessary, reinforced walls can be integrated with gravity walls to keep a consistent look on the face of the walls throughout the project.
“What I like about [this gravity wall system] is that it gives me the ability to bury the wall as much as I need to, and really provides an aesthetically pleasing wall without having to worry about form liners. It’s durable and cost-effective,” Melville said.
The Ledgestone and limestone textures blended in with the urban environment and made the pedestrian amenities look more inviting, as well as fulfilling their functional purposes.
The knob-and-groove interlocking system allows the blocks to be stacked like giant Lego blocks, which simplifies installation. The blocks also are stacked with heavy machinery, which cuts back on labor and cost for a large crew.
The project team managed to keep construction within tight property lines.
Building the Walls
The retaining walls allowed designers to create multiple structures with two coordinating looks. These solutions contributed to the project’s success by providing solutions to build a lot in a short time frame.
According to the city of Albuquerque, the $93 million project was completed on time and on budget with joint effort from local, state and federal governments.
A mix of gravity and reinforced walls were put in place, ranging from 12 to 15 ft in height, and totaling 8,050 sq ft. This helped create ADA-accessible walkways and bike trails that connect to the existing regional trail system and the pedestrian I-25 bridge, as well as create a better overall system for a heavily used urban roadway.
A second wall was used on this project to create a deceleration ramp for better access to the adjacent private property, which will be home to a new Cabela’s store, according to New Mexico Redi-Rock manufacturer Materials Inc.