One of Minneapolis’ most iconic landmarks, the James J. Hill Stone Arch Bridge, is being restored using several products from TCC Materials. American Masonry Restoration of Fridley, Minn., is repointing, repairing, and replacing limestone on the 2,100-foot-long bridge, which temporarily closed in April and is expected to reopen in 2025.  

AMR repointed and stabilized the bridge prior to starting the repair and replacement of limestone. The team used Spec Mix Type S and N White Mortar; each has variable amounts of white Portland cement, lime, and sand to reach desired strengths needed. The Type S mortar was used to repoint the “Skyview” joints along the top of the bridge, and Type N is used for the joints running along the side and arches within the first 4 inches of depth. 

“We typically use Spec Mix Type O on historic preservation projects, but because this is a structural project, we needed a tougher product,” said Dustin Sly, project manager for AMR. “We tested several products but went back to the Spec Mix Type N that we tested first.”  

The company engineered a custom rigging system to place the stones — sourced from quarries in Minnesota and Iowa just like the original build — and has replaced 438 stones in the first phase of the project. Tenon Construction Grout is used as a flowable mixture that is pumped behind the replacement stones and around steel anchor bolts. 

Next spring, AMR will replace about the same number of stones in phase two, which will focus on the west end curve that approaches downtown Minneapolis.   

American Masonry Restoration is an award-winning masonry restoration firm in the Upper Midwest that has provided its expertise and craftsmanship for some of region’s most iconic historical structures. Kraemer North America is the general contractor for the $38.5 million project, which improves the structural condition of the bridge while preserving the bridge for future generations.   Built between 1881 and 1883, the bridge last carried rail passengers in 1978. Today it offers unparalleled views of the Mississippi River, St. Anthony Falls, and the Minneapolis skyline. Named a National Historic Engineering Landmark in 1974, the Stone Arch Bridge has served as a pedestrian and bike trail since the early 1990s and is part of the Minneapolis Parks District’s St. Anthony Falls Heritage Trail. It is the only arched bridge made of stone on the Mississippi River.