Geotechnical and Structural Engineering for Old Historical Buildings
Geotechnical and Structural Engineering for Old Historical Buildings
The preservation of historic buildings requires strengthening and underpinning of foundations whose geometry, condition, and geotechnical environment are only partially known. Successful rehabilitation needs an integrated geotechnical and structural engineering approach combined with practical construction experience. This paper presents two case studies involving the strengthening of historic masonry structures founded on problematic soils. The first case concerns Alexander Street in Helsinki, Finland, a building dating from approximately 1840. Investigations showed that part of the structure was founded on silty clay that continued to deform under loading despite more than 150 years service. The corridor foundations were successfully underpinned using as shoring drilled and grouted steel piles for new reinforced concrete piers. The second case, St. Johns Church in Tartu, Estonia, was constructed in the late thirteenth century. The church foundations consisted of masonry resting on timber rafts over loose sandy silt. Long-term settlement and groundwater lowering required extensive underpinning of the tower, walls, and columns using jacked piles, drilled spiral piles, and piled raft foundations. In addition, the destroyed Line B section of the church was reconstructed. A practical design method based on Lower Bound Theorem of Plasticity is presented for the design of floating piled strip foundations and for soil-foundation-pile-slab interaction. The method combines geotechnical requirements related to bearing capacity, settlement, and angular distortion with structural requirements by Upper Bound Theorem related to plastic rotations, bending moments, and crack control. The case studies demonstrate how soilfoundationstructure interaction principles can be applied in the rehabilitation of historic structures.
Keywords: Historic building foundations, plastic state of silty clay, jacked and spiral piles, upper and lower bound theorems of plasticity, spring coefficients of piles
Kari Christer Avellan; Kirsi Vaali; Erika Belopotocanova
4th International Symposium on the Preservation of Monuments and Historic Sites
Restoration Engineering and Structural Interventions
https://doi.org/10.53243/tc301-2026-29