Versatile wall system adds ease, beauty to N.M. abutment project

By: Kevin Loe

The central New Mexico corridor contains about half the state’s population, with many commuting between Albuquerque and Santa Fe each day. The 4-lane interstate, which connects the two cities, was becoming increasingly congested, but expansion of the freeway was not feasible.

In 2003, New Mexico Gov. Bill Richardson was instrumental in making the new commuter train a reality. Prior to construction, NMDOT purchased the railway from BNSF, which gave the commuter trains priority over freight trains.

In several places, the rail line passed above or below roadways, which necessitated bridge construction. To flank the bridges, prevent erosion and provide an aesthetic finish, the bridges required abutments.

After reviewing some of the key elements of the project, engineers determined they needed a versatile wall system that could be used in several different applications requiring varying batters. Aesthetics and ease of installation also were important. Based on these factors, engineers agreed that Redi-Rock was the best choice for the walls along the railway.

Project engineers liked the versatility of the wall system, as they were able to design both gravity and reinforced walls for bridge abutments as well as retaining walls. In total, the project required six walls comprised of 2,164 blocks, or approximately 12,440 sq ft of retaining walls. Plus, two walls required a zero-degree batter to allow them to abut box culverts and three walls required custom blocks to accommodate drainage pipe.

On the Rail Runner project, engineers at MacCornack Engineering, HNTB and Materials Inc. worked together to design both gravity and reinforced walls in a limestone texture. The tallest wall stands approximately 20 ft tall.

To blend in with the native earth tones, several of the higher-visibility walls were stained to blend in the landscape after construction was completed.