The Dublin Link
Project of the Year Finalist and Best Project
Owner: City of Dublin
Construction Manager/General Contractor: Kokosing
Lead Design Firm: T.Y. Lin International
Civil Engineer: EMH&T
Civil Engineer (approaches): Resource International
The Dublin Link, a span connecting the Columbus Ohio suburb’s downtown with the Dublin Riverside Park development across the Scioto River, is the longest single-pylon, S-shaped bridge in the world with a 760-ft-long S-curve alignment. The superstructure passes through a focal tower element—a needle-hole concrete pylon—and the main suspension bridge span is 500 ft long with four 65-ft approach spans. The steel box girder is an asymmetric V, which appears to change shape when crossing the bridge and yet still maintains a 14-ft clear deck width from end to end. The tower is 176 ft tall and stretches 110 ft from the walking surface to the top of the pylon.
Dan Fitzwilliam, senior bridge engineer in the San Diego office of T.Y. Lin International, leads a group that designs bridges for pedestrians and cyclists. His team used LARSA, the Grasshopper plug-in for Rhino 3D and some proprietary T.Y. Lin International design tools to make the geometric shape of architect Endrestudio’s architectural splines, helping Dublin fulfill its aim of having a bridge that would be a signature crossing and represent connectivity and inclusivity.
“Grasshopper sometimes requires you to program as you design, but we like it because it has the parameters to deliver the kind of shapes they wanted,” Fitzwilliam says. “It allowed us to create iterations that divined the best design solution, in this case, the steel box girder.”
The bridge features one main suspension cable with a single plane of hanger cables attached along only the inside edge of the curved bridge deck. Dynamic programmable lighting allows the city to change the look and color scheme of the bridge at night to match desired themes.
Recognizing the challenging nature of many of the critical design features of the bridge, Dublin adopted a construction manager-general contractor delivery method, similar to CM at-risk, a first in the state of Ohio. The design team worked to develop the project schedule. GC/CM Kokosing was able to deliver the project despite delays from suppliers in Europe. Close collaboration among the team was required for the main suspension cable and hanger cables. The cables were tested after fabrication in Italy, delivered to the site and installed in the bridge in time to satisfy the schedule.
“I've never seen one with that triangular shape. There was a project 10 years ago we did that was more trapezoidal, a wedge-shaped box, but with a pure triangle shape with varying width of the top plan, that was very unique,” says Kyle Stalder, project engineer for contractor Kokosing