Abstract:
In restoration and upgrades of historical structures, underpinning is often required to stabilize or improve bearing of shallow foundations. Design solutions often require manual excavation beneath the structure or drilling through the foundations to install new supports. Where historic brick and masonry are too fragile to permit these processes, alternative approaches are required. This paper presents an approach for jet grout underpinning of historic masonry bridge without requiring drilling through, or excavation beneath existing foundations. The jet grout columns are intended to improve the bearing capacity of the foundations and contain soil and rubble underneath the foundations. The design methodology includes increasing bearing capacity and foundation stiffness and can be adjusted to the requirements for individual foundation elements. The flexibility of jet grouting allows development of complex orientations that effectively support the foundation. This paper presents the methodology for analysis and design for these jet grout underpinning elements where no excavation is required. Keywords: jet grouting, historical structures, underpinning, bearing capacity