Bridge Approach Settlement Solutions in Alamogordo, New Mexico

Problem

In Alamogordo, New Mexico, a major series of bridges connecting to Holloman Air Force Base (AFB) was in dire need of stabilization and pavement leveling. Several of the bridge approaches and departures had settled up to 4”, causing massive drainage issues. The median along the entire stretch of bridges had also settled, further exacerbating the settlement and drainage. The bridges had to be safely stabilized to support the heavy military equipment transfer route and constant civilian traffic. The client was looking for a long-term solution to the settlement problem that would provide a smooth and safe ride for drivers with as little construction impact to the community as possible.

Analysis

URETEK arrived on location to inspect the situation and consult with the client about a proposed solution. The structures were built on gypsum and landfill, both of which are very unstable. Dynamic Cone Penetrometer (DCP) testing confirmed that the base and sub-base soils had lost compressive strength and that the soft gypsum could no longer bear the traffic load. URETEK Deep Injection® (UDI) was proposed for the project as a quick and effective way to stabilize the underlying materials while providing a lift to the settled area.

Solution

For the bridge settlement project in Alamogordo, UDI was the perfect solution to lift the roadway back to grade and stabilize the soils below. Crew members injected URETEK 486 Star® polymer into the gypsum at -4’, -8’, and -12’ beneath the pavement system according to a site-specific injection plan. Throughout the project, technicians employed laser monitoring to ensure proper controlled lift of the settled roadway.

Result

UDI stabilized the bridges, restored structural integrity to the soft foundation, and ensured a safe and comfortable ride for civilian and military drivers. The previously significant dips were brought to grade, and the soil was stabilized, resulting in a secure bridge system and access to and from Alamogordo and Holloman AFB. After years of dealing with unstable foundation materials, the client was pleased to finally have a long-term repair in place without having to deal with the steep costs and long project timelines associated with traditional methods.

URETEK Deep Injection® (UDI)

Widely referenced throughout our industry, UDI involves the injection of the structural polymer into base and subgrade soils to increase the load-bearing capacity. This is achieved by injecting the polymer through small holes drilled directly through the pavement structure to depths determined by site-specific analysis. Our URETEK 486 Star® material flows easily into voids and weak zones within the soil mass below. Through a controlled chemical reaction, the expanding polymer compacts surrounding soils and applies controlled pressure on targeted areas of the affected pavement above. If needed, a multi-injection design plan is utilized to gently return the pavement to its original grade. The composite material quickly cures into a strong, dimensionally stable, and water-resistant geo-material, providing years of reliable service.

URETEK 486 Star®

URETEK 486 Star® polymer is a two-component, high-density, expanding thermoset polyurethane system. It was developed to be the ideal solution for under-sealing, void filling, lifting of settled pavement, stabilization and stiffening of weak soils, and for encapsulating and sealing buried infrastructure. URETEK 486 Star® is environmentally inert, non-toxic, and resists underground water erosion or weakening due to its industry-leading hydrophobic properties.