Restoring Settled Bridge Transition Slabs in Utah
Problem
Antelope Drive in Clearfield, Utah, had two bridges (F-581 and F-582) whose approach and departure slabs needed rehabilitation. The slabs on both structures had settled as much as two inches from years of heavy traffic. As the settlement increased, the impact energy imparted to the slabs and bridge also increased, creating a positive feedback loop of more slab settlement. The settlement and resulting dips in the roadway needed to be repaired to restore safe traffic flow.
Analysis
URETEK made a site visit to evaluate the extent of slab settlement on the bridge to roadway transitions, and to approximate a cost for the repairs. URETEK performed six rounds of Dynamic Cone Penetrometer (DCP) testing to fully analyze both the approach and departure sides of the F-581 and F-582 bridges. The results of these tests revealed several weak soil zones beneath the slabs that would benefit from polymer stabilization.
Solution
URETEK targeted the weak soil layers with URETEK Deep Injection® (UDI) to lift and stabilize the slabs and to prevent future settlement issues. URETEK worked in conjunction with ProTech who was restoring the concrete bridge deck. URETEK coordinated with ProTech to minimize lane closures during the repairs.
Result
All four of the approach/departure slabs for bridges F-581 and F-582 were lifted between one and two inches. This repair smoothed out the roadway to restore safe driving conditions to the busy thoroughfare. URETEK successfully restored the bridge to roadway transitions on schedule and prevented future slab settlement by addressing the underlying weak soil zones.
URETEK Deep Injection® (UDI)
Widely referenced throughout our industry, UDI involves the injection of 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 a 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.
