It is proposed to build an 8-story building with a footprint of 20 m x 30 m, resting on a mat foundation of the same dimensions, in a saturated clay with undrained shear strength of 60 kPa. Assume approximately 12.5 kPa per floor for dead and live loads. Unit weight of soil is 18kN/m3 . a) At what depth would you place the mat to make this a fully compensated foundation? b) What would be the depth of this mat foundation for the net factor of safety of 5? c) What is the gross factor of safety for the depth determined in the answer to question b)?

It is proposed to build an 8-story building with a footprint of 20 m x 30 m, resting on a mat foundation of the same dimensions, in a saturated clay with undrained shear strength of 60 kPa. Assume approximately 12.5 kPa per floor for dead and live loads. Unit weight of soil is 18kN/m3 . a) At what depth would you place the mat to make this a fully compensated foundation? b) What would be the depth of this mat foundation for the net factor of safety of 5? c) What is the gross factor of safety for the depth determined in the answer to question b)?

Principles of Foundation Engineering (MindTap Course List)

8th Edition

ISBN:9781305081550

Author:Braja M. Das

Publisher:Braja M. Das

Chapter8: Mat Foundations

Section: Chapter Questions

Problem 8.5P

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A load of 800 Kip will be distributed on a circular foundation with a diameter of 20 feet, this structure will be located on the existing ground. The soil at the site has a unit weight of 105 lb/ft^3. Prepare a situation diagram to determine the vertical effective stress (lb/ft^2 no decimals) after building and loading the foundation at a point located: a) 12 feet below its center. b) 12 feet below its edge.
An office building is to be supported on 150 ft : 300 ft mat foundation. The sum of the columnloads plus the weight of the mat will be 90,000 k. According to a settlement analysis conductedusing the techniques described in Chapter 8, the total settlement will be 1.8 in. The groundwatertable is at a depth of 10 ft below the bottom of the mat. Using the pseudo-coupled method,divide the mat into zones and composite each zone. Then indicate the high-end and low-endvalves of ks that should be used in the analysis.
It is proposed to build an eight- story building with a footprint of 15 m x 20 m, resting on a mat foundation of the same dimensions. Mat foundation is located in saturated clay with undrained shear strength of 60 kPa and unit weight of 20 kN/m3 . Assume approximately 15 kN/m2 per floorfor live and dead loads (together). a) At what depth would you place the mat to make this a fully compensated foundation?b) What is the gross factor of safety of the fully compensated foundation against the bearing capacity failure?
Q3. A mat foundation is shown in figure below. The design considerations are L 12 m, B -10 m, Df 2.2 m, Q = 30 MN, x1 =2 m, x2 2 m, x3 -5.2 m, and preconsolidation pressure oe = 180 kN/m?. Calculate the consolidation settlement: under the center of the mat. • Under the corner of the mat Size of mat = BXL Sand Dr y = 16.0 kN/m3 X1 Groundwater table Sand Yeat = 18.0 kN/m Clay = 17.5 kN/m3 EYsat e, = 0.88 C = 0.38 C; = 0.1
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o T ☺ ť Q2: A ring foundation having load equal to 400kPa is resting on a saturated clay soil layer, the groundwater level is at the natural ground surface. The outer diameter of the foundation ring is 8m. Find the inner radius of the ring foundation if the total stress at a point located 4m beneath the center of the ring foundation equal to 251kPa, knowing that the saturated unit weight of the clay is 16kN/m'. (Use the below formula) Solution:- Aoz = q مر ر ل لأعلى لاستعراض الفلاتر إضافة شرح.. . mum <
It is proposed to build an 8 story building with a footprint of 15 m X 20 m, resting on a mat foundation of the same dimensions, in a saturated clay where cu = 50 kN/m², y = 19.0 kN/m³. Assume approximately 15 kN/m² per floor for the live and dead loads. a. At what depth would you place the mat to make this a fully compensated foundation? b. What should be the factor of safety if the mat is placed at 3.0 m depth?
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绘图编辑 3.12 For a strip foundation, the width is 1.2m, buried depth is 1.2m, the standard value of the load applied on the foundation F=155KN/m, the soil layer is distributed as follows: from the ground to the depth of 1.2m is the land fill, =18KN/m³; the depth in the range of 1.2~1.8m is silty clay, fak=155kPa, E,=8.1Mpa, y=19KN/m³; below the depth of 1.8m is the mucky clay, fak=102kPa, E,=2.7Mpa. Try to check the base pressure and the bearing capacity of the weak sub-layer. Ground F=155KN/m OLand fill 18KN/m³ 1.2m O Silty clay La-155kPa;E-8.1Mpa;y-19KN/m³ -0, 1.0 O Mucky clay -0, H1.0 Sak-102kPa;E,-2.7Mpa 1.2m
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A foundation carries uniform loads as shown. Determine the value of w (in kN/m). 70 kNlm 111 4m 2m tuzt wat fwet it h twetwit