<p><p><figure id='attachment_3474' style='max-width:432px' class='caption aligncenter'><img class="wp-image-3474 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photograph of project on the Glenn Jackson Bridge wherein injected lightweight foam fill was used to fill a void in an end panel of the bridge." width="432" height="287" /><figcaption class='caption-text'> Photo from Bruce Ely/The Oregonian</figcaption></figure></p><p><div><h2>Project Summary/Scope:</h2>A void developed at the end panel of the southbound Interstate 205 Glenn Jackson Bridge and the adjacent slab of the exit ramp. The void was apparently caused by water eroding the subgrades. Injected lightweight foam fill was used to fill the voids and lift the concrete slabs.</p><p>Based on initial profiles along the two sides and the center of the exit ramp, 90 to 100 mm (3.5 to 4 inches) of pavement lift was designated.</p><p>Six 16-mm (5/8 in) diameter holes were drilled to a depth of 500 mm (20 inches) in multiple locations and then injected with polyurethane fill. Injection started from one side of the ramp moving across to the other side of ramp. Injection through six holes was repeated several times until the desired profile was obtained. After the lift process was completed, additional holes were drilled with a center space of 1.2 meters (4 feet) to fill any preexisting voids or voids formed by the injection process. All the holes were then sealed with a cementitious grout.<br><h2>Performance Monitoring:</h2>String lines were used to monitor elevation of the pavement. The roadway settled at all 12 test positions with a maximum decrease in elevation of 10.5 mm (0.4 inches) two years after injection. The decrease in elevation of the roadway in the first three months averaged 4.0 mm (0.16 inches). New cracks appeared in the end-panel four days after injection.<br><h2>Cost Information:</h2>The total cost of the project was $42,260. 2,130 kg (4,700 lb) of polyurethane was used at a unit price of $20/kg ($9/lb).<br><h2>Project Technical Paper:<strong> </strong></h2>Soltesz, S. (2002). Injected Polyurethane Slab Jacking, Report FHWA-OR-RD-02-19, Oregon Department of Transportation and FHWA, 34p.<br><h2>Date Case History Prepared:</h2>November 2012</p><p></div></p></p>