Tutorial - Pile Foundations 1 - Canvas PDF

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9/7/20

Geotechnical Engineering 3, CIVE1159 TOPIC 1 Pile Foundations Tutorial Part 1 A/Prof Abbas Mohajerani (PhD) Reference: Chapter 13, Soil Mechanics and Foundations Third Edition Muni Budhu

The materials used in these 10 slides are copyright and are based on the textbook “Soil Mechanics and Foundations”, by Muni Budhu, 3rd edition, with copyright John Wiley & Sons, Inc. (as outlined in the book).

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Pile load test: In most large projects, a specific number of load tests must be conducted on piles. The primary reason is the unreliability of prediction methods. The vertical and lateral loadbearing capacity of a pile can be tested in the field.

Problem 13.2

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Solution 13.2 • Guideline: • Results from a pile load-displacement is given and the load corresponding to a displacement (settlement or serviceability limit) of 12 mm is required. We need to plot the results in scale and find the Load at 12 mm settlement from the figure, as show in the next slide.

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Solution 13.2 Part c • Discussion: Regarding the answer in part (b), the ultimate load is not always clear. • For example, another method to find the ultimate load from the above figure is to find the intersection of the tangents of the 2 parts of the curve. The load corresponding to this intersection point can be selected as the ultimate bearing capacity. Please try to find this ultimate load and compare it with the maximum load

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Solution 13.2

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Bearing Capacity of a Pile Problem 13.4

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Problem 13.4 (Fig 13.4)

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Solution 13.4

Guideline: Please read and understand the contents in lecture slides 39 to 42 and example 13.4 in slides before doing this problem. If you have any questions, feel free to send me an email or ask me in our tutorial class. In this problem, we have to assume a length for the pile and calculate the ultimate bearing capacity and then the Factor of Safety for the applied load (275kN). For this problem FS should be greater than 2.

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Solution 13.4

Layer 1 is the length of of pile in the soil above the water level and Layer 2 is the length of soil below the water level. We have to calculate effective stress in the middle of each layer and find the skin friction for each layer and then the total skin friction. RMIT University©

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Solution 13.4

We should remember that Factor of safety = Qult / vertical applied load on the pile which is 275 kN.

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Solution 13.4

I will discuss this solution further in our tutorial class.

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Solution 13.4

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