Keller conducted the structural and geotechnical remediation program using limited access equipment with no major distress to the historic property and its structures.
The St. Vrain Mill is a historical building located on Highway 434 in the Mora Valley originally established in 1864 by Ceran St. Vrain to supply flour to Fort Union. The mill is being renovated to serve as a cultural center for the community. Medium dense sands and gravels were encountered to a depth of 20 feet. Groundwater was encountered at five feet below grade.
Differential settlement across the building footprint resulted in significant structural damage, including cracks up to eight inches wide. Structural and subsurface remediation was required to restore the building to serviceability. Because the original building needed to remain in place, any repair and remediation program would need to be conducted in limited access conditions while avoiding any additional structural distress on the historic building.
Keller performed permeation grouting to stabilize rubble foundation materials and the immediate soil to within four feet of the surface. Afterward, compaction grouting was conducted to increase the density of existing soils to 20 feet below grade. Specialty drilling equipment was used to safely install grouting locations near the canal that once powered the mill.