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SSI Modeling Challenge

Original Post - 15 Jul 2020 - Michael H. Scott

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I know enough soil-structure interaction (SSI) to be dangerous. This means I’m no expert in the subject, only someone who is capable of describing an SSI modeling challenge.

The subject of this challenge is the soil-bridge model shown below. The model is based on research by a former M.S. student and a couple colleagues in Eastchester on earthquake-tsunami multi-hazard effects on transportation structures. The colleagues are still here, but the student went on to do a Ph.D. and post-doc in another US west coast college town that also has a Woodstock’s Pizza restaurant.

Column-pile system for SSI modeling challenge

The column/shaft is a 1.1 m diameter reinforced concrete section and the soil is a dense sand with relative density Dr=90%. You can find more details on the soil-bridge model here, but for this challenge, I’d like to keep the model simple. I don’t want variance in the results to be attributed to approximations of concrete stiffness.

So, let’s say the column/shaft is linear-elastic with modulus E=25 GPa. Also, let’s assume free field conditions in formulating the soil resistance and a pinned condition at the base of the shaft.

What is the horizontal displacement (units=mm) at the top of the column?

E-mail me your answer by August 31. You don’t have to use OpenSees, but please let me know how you modeled the soil.

I look forward to your responses. I will share anonymized results in another post after the deadline.



RESULTS