Because of the high traffic volumes, work was performed at night during the hours of 7 p.m. to 6 a.m. to minimize the impact on the traveling public. One of the challenges was the lack of adequate bid quantities to do all the necessary repairs. The full-depth slab replacement quantities were increased by 65 percent to allow the repair of all intersecting concrete streets, utility cuts and proper patch length between joints. Some of the joint widths were in excess of 5 inches, due to longitudinal shifting of the concrete slabs over time. It was decided to use a hot pour sealant rather than a silicone sealant, as originally proposed. This triggered a change order to reflect the new material and price difference for the project.
Another major challenge was the location of utilities within the pavement system. The contractor uncovered leaking water valves and sewer lines and cut through unmarked utility conduits. At some point in time, 16 conduits (multiple utilities including three each of fiber optic, copper and 1800 lines) were placed in the concrete slab over a culvert, which were discovered when the contractor made sawcuts for a slab repair.
One of the most surprising events to occur was the overnight settlement of a sawcut section due to a void underneath. It was discovered during a routine morning inspection and the DOT maintenance department was immediately called to divert traffic. An investigation found that a broken sewer pipe had caused a washout. After the street flooded night after night, the problem was discovered — old equipment. Just as the road itself was old, the utilities buried beneath it were aging. The old water valve was replaced and construction continued.
The broken pipe was not the only water issue the crews faced. Being so close to the Cooper River, tidal influences made an impact. At extreme high tides, the water table rose, affecting the work area, and facilitating the need for pumps. The contractor kept temporary stone fill on site to use when base levelling was needed. More than once, the patch being worked on had to be left open — and blocked off to traffic — while the base was allowed to dry.
Despite all the challenges along the way, the result was a successfully rehabilitated roadway. With a smooth, pothole-free surface, the higher traffic volumes can now be easily accommodated. According to Sarah Hamrick, project manager, SCDOT, the most unique aspect of this project was the age of the existing concrete, which had not been rehabilitated since the placement of the original PCC in 1936. “The final product was a relatively smooth ride with satisfactory results. It was an enormous improvement from previous conditions,” Hamrick says.
The repairs may have only been on two miles, but the work involved extensive challenges along the way. If subsequent maintenance is timely on the roadway and utilities, future repairs will be quicker and easier. All in all, it is a substantial feat for a road to last 75 years without significant repairs. “Now, instead of a rough road that wears out drivers’ patience and their tires, Rivers Avenue sets the standard for other facilities of its kind. In an era where the reuse of existing resources is a smarter and greener choice than building something new, this project proves that quality rehabilitation work can stand the test of time,” Hamrick says.
With a total project value of $2,393,788, the project was completed in December 2010.