Special Construction and Geotechnical Considerations in Deep Foundation of Vaudreuil-Soulanges Hospital Center in Greater Montreal Area-Paper

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The Vaudreuil-Soulanges Hospital Center in Greater Montreal required a large deep-foundation system built under demanding geological and schedule constraints. The site has thick Champlain silty clay over till and highly abrasive, strong sandstone bedrock. Because shallow foundations could not meet settlement and structural requirements, the project used 519 reinforced-concrete drilled shafts, generally 1.2 or 1.5 m in diameter, with an average 15 m of overburden and 4.5 m rock sockets.<br /><br />Close collaboration between the designers and contractor enabled design and construction optimization. Full-scale axial and static and cyclic lateral pile tests showed greater lateral capacity than predicted by conventional empirical methods and supported reductions in pile quantities and optimized socket lengths. Site-specific seismic analysis also informed structural design. The foundation works were completed in nine months using up to seven rigs operating two shifts, seven days a week. Cluster drilling was selected for the hard, abrasive sandstone, although it required substantial equipment maintenance and contributed to higher-than-expected concrete consumption.<br /><br />Durability was a major concern because the piles would be in direct contact with chemically aggressive soil and groundwater and had a 75-year design life. A project-specific tremie concrete mix was developed to provide low permeability, sulfate resistance, and up to six hours of workability. Testing and quality controls addressed durability, thermal behavior, placement, and concrete stability.<br /><br />The project also required extensive groundwater management and coordination around rock-socket inspections. Overall, the paper demonstrates how field testing, tailored concrete design, effective quality assurance, and strong designer–contractor cooperation helped deliver a complex foundation system safely and efficiently.

Keywords

Vaudreuil-Soulanges Hospital Center

deep foundation

drilled shafts

Champlain silty clay

rock sockets

sandstone bedrock

pile load testing

tremie concrete

groundwater management

foundation optimization