August 12, 2020 ITS Money: Riad Diab, Ph.D., P.Eng., P.E.

Riad Diab, Ph.D., P.Eng., P.E. | SNC Lavalin

Design of Large Diameter Single Drilled Shafts Supporting the 650-Span Structure for the REM Project in Montreal using Axial and Lateral Static Load Tests

In 2018 a $6.3 Billion Design-Build contract was awarded for the design and construction of the Réseau Express Metropolitain in Montreal, Canada. About 1/3 of this project will be constructed on an elevated structure founded on large diameter rock-socketed drilled shafts. To optimize the design, two full-scale, bidirectional static load tests and two fully-instrumented lateral load tests were performed. These tests resulted in shorter shafts, reducing the project costs and mitigating construction issues associated with long shafts.

Findings

• The cost to install the sacrificial drilled shafts was $105,000 and with the cost added to perform the tests themselves, the total cost of the test program was approximately $300,000.
• The information gained from the test program resulted in a savings of approximately $45,000 for each shaft.
• With a total of 650 shafts in this project, the total project savings were more than 29 million dollars.