Widening of SC Route 6/60 Over Lake Murray Dam
Lexington County, SC
The SCDOT identified the need to widen the existing 2-lane route. With Lexington County being the fastest growing county in the state and a rapid rise in the volume of daily traffic traversing this corridor, congested north and southbound traffic was mounting, as were the number of traffic accidents. At the center of these traffic and safety issues was the daunting 2-lane, 1.5 mile, 75 year old Lake Murray earthen dam, which was controlled by South Carolina Electric & Gas. Of major challenge was how to widen the corridor and expand capacity of dam traffic without any interruption in traffic flow while maintaining safe conditions for travelers and minimizing impact to the surrounding neighborhoods throughout a two and a half year construction period. Our innovative design solution included replacement of the original 2-lane bridge constructed atop the emergency spillway gates adjacent to the Lake Murray Dam. After detailed studies, the decision was made to design and construct an entirely new structure without affecting the function of the spillway gates. Located immediately upstream of the spillway structure, the bridge replacement required much coordination with South Carolina Electric and Gas and the Federal Energy Regulatory Commission (FERC). The bridge had to be evaluated for three different earthquake magnitudes to satisfy both SCDOT and FERC requirements.