Blythe Construction was contracted to build a twin arch structure over U.S. 52 along the Salem Creek Connector to create a gateway to the southern area of downtown Winston-Salem. The contractor asked KCI to provide the structural engineering needed to build the arches. Due to the arch’s large size, components had to be transported in 11 pieces that were then bolted together at splice locations. Our team was responsible for designing the rigging details and ensuring there was a system in place to adjust the pieces during the lift if needed. Engineers used a visual analysis software to create a 3-D model to analyze the stresses in the arch, estimate deflections, ensure stability and check all crane lifts.
Our experience with setting steel bridge girders on other similar projects was key to giving us a comfort level to take on this project.
Andrew M. Craig, PEPractice Leader
One of the biggest challenges associated with the design was the rigging required for the legs. If the nylon slings were not exactly the right length or if the weight distribution was not exactly as calculated, the leg would not sit in the correct orientation. In order to ensure that the pieces could be adjusted during the lift, a system was devised to use a secondary auxiliary line of the crane to adjust the component, if needed. The system worked flawlessly and all pieces fit together without complications. Thanks to proper planning and communication, Blythe completed the project smoothly and without complications.