Question

You must determine the number of aggregate piers you need to reduce the settlement under a rectangular foundation of a column of a 6-story parking structure. The aggregate piers should be 3 ft in diameter. The maximum post-treatment settlement is 1.5 inches. After you have determined the number of aggregate piers that is required, determine the post-treatment settlement in the soil. Use the 2:1 approximation method to estimate the vertical stress under the center of the rectanqular shallow foundation. Site Conditions: A 6m thick layer of fine-grained material underlaid by a thick ,dense, strong soil layer. Pressure from foundation: p = 600 kPa Footing size: 3m x 3m Mne-gained soil- 12 MPa (constrained modulus)= M.100 =MPa (constrained modulus)= Settlement reduction ratios and corresponding area improvement ratios are listed below. Use linear interpolation to approximate n values in between the listed values.

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