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Term Project Paper on Design of Shallow and Deep Foundation for a cement plant in Columbia

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Rakibul Hasan,MEng,EIT
Rakibul Hasan,MEng,EIT

•Designed foundations for given loads and conditions using PLAXIS and L-Pile for the design-analysis. •Used Microsoft Excel for developing formulas and calculated capacity, lateral capacity, settlement, group pile settlement and lateral deflection of footing to yield best economical and sustainable design.

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1 Term Project Paper on Design of Shallow and Deep Foundation for a cement plant in Columbia Submitted by J M RAKIBUL HASAN (250821180) 24th April 2015 Graduate Program: Foundation Engineering Professor M. Hesham El Naggar The School of Civil and Environmental Engineering The University of Western Ontario London, Ontario, Canada An Assignment submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Civil and Environmental Engineering
2 Content 1. Project Background………………………………………………………………………….1 2. Project Description…………………………………………………………………………..1 3. Soil profile of Cement Plant…………………………………………………………………1 4. Design Conditions……………………………………………………………………………1 5. Design Expectations………………………………………………………………………….2 6. Scope of work………………………………………………………………………………...2 7. Design Criteria……………………………………………………………………………….2 Shallow Design 1………………………………………………………………………..3 Capacity Calculation…………………………………………………………...4 Settlement Calculation…………………………………………………………5 Plaxis Analysis…………………………………………………………………..7 Shallow design 2………………………………………………………………………...7 Capacity Calculation……………………………………………………………7 Settlement Calculation………………………………………………………….10 Plaxis Analysis…………………………………………………………………..11 Deep Design……………………………………………………………………………..13 Capacity Calculation and Pile parameters…………………………………....13 Single Pile Settlement Calculation……………………………………………..14 Group Pile Settlement Calculation…………………………………………….15 Lateral Capacity Calculation…………………………………………………..16 Lateral Deflection Calculation…………………………………………………17 8. Results of All Design Criteria……………………………………………………………….18 9. Recommended Design for Client…………………………………………………………....19 10. Appendix…………………………………………………………………………………….21 11. References…………………………………………………………………………………...27
3 1. Project Background My given Project work is to design shallow and deep foundation for a Cement Plant. A cement plant is a structure for grinding, mixing and processing Cement of various kinds for constructional purpose. From a foundation engineering point of view the loading pattern of a cement plant on existing foundation is not constant because after grinding and processing the cement materials are taken away from plant and the amounts are not always the same. So the live load on existing ground level may change rapidly but I have to design a foundation for the maximum live load from a cement plan. 2. Project Description My Project structure is Situated in Columbia, a country situated in the northwest of South America, The soil between depths of 8 and 25 inches, (20 to 64 cm) is moist in some or all parts from late October to late May or June and is dry in all parts the remainder of the year, unless irrigated. The 10 to 40 inches, (25 to 102 cm) particle-size control section is stratified fine sandy loam, very fine sandy loam, silt loam, loam, loamy sand, loamy fine sand, fine sand or sand and averages 10 to 18 percent clay, when mixed, and has greater than 15 percent fine sand or coarser. Up to 35 percent gravel may occur below a depth of 40 inches, (102 cm). Redoximorphic features occur between 10 and 48 inches, (25 to 122 cm). Content of organic matter decreases irregularly with depth. 3. Soil profile of Cement Plant A geotechnical investigation was conducted to determine the soil parameters required for the design, which 5 boreholes, BH‐5 to BH9 that extended to 60.0 m below ground surface. The site generally consists of around 1.5 m of fill, followed by natural (native) cohesive (sandy silt clay, sandy clay, lean clay, fat clay, silty clay, and clayey silt). Undisturbed soil samples were retrieved using thin walled Shelby tubes and were used to determine the undrained shear strength and deformation characteristics. In addition, geophysical study was conducted to determine the dynamic soil properties of the site soils. The results from the field and laboratory tests are provided in Tables 1‐4 of Appendix. 4. Design Conditions It is required to design a foundation system to support a cement mill. The total static (dead) load of the mill and associated equipment is 8,820 kN and the total operating load (dead + live loads) is 25,100 kN. The top of concrete of the proposed foundation will be at the existing ground elevation and the thickness of the foundation will be 5.0 m. To accommodate the mill and the associated equipment, the foundation (or pile cap) has to be square with minimum side length of
4 20.0 m. The maximum (total) settlement allowed is 30 mm. The plant is located in a seismic zone characterized by peak ground acceleration of 0.2 g. 5. Design Expectations Different foundation options are considered for supporting the proposed mill, including: 1. Shallow Foundation 1) Shallow foundation resting on the native soil at depth 5.0 m below existing grade. In this option, the design soil parameters that should be used in the design are based on the measured properties presented in Tables 1‐4 and Figures 1‐4; 2) Shallow foundation option resting on improved soil (using the soil mixing technique) between depths5.0 and 25.0 m below grade. In this option, the cement‐soil mixing technique with result in minimum undrained shear strength of the improved soil, Su = 100 kPa. The soil improvement technique will also reduce the compression ratio by at least 50%, i.e., CR improved soil = CR native soil/2; 2. Deep foundation 1) The preferred deep foundation option is drilled cast in place piles. The available equipment allows the construction of piles 0.60, 0.90, 1.20 and 1.50m diameter. 6. Scope of work This is a practical problem for given loads and conditions. So different foundation system can be compared to find the best foundation option for a client. Engineering Recommendation and discussions on designed length, width, depth and other parameters of concrete foundation can really pave the way of an economical solution 7. Design Criteria Shallow Deep
5 Shallow Design 1 1) Shallow foundation resting on the native soil at depth 5.0 m below existing grade. In this option, the design soil parameters that should be used in the design are based on the measured properties presented in Tables 1‐4 and Figures 1‐4; Given Data Depth eO CR RR m Mr j OCR Pc 5.55 0.404 0.078 0.014 29 164 0 5 343 9.9 0.896 0.132 0.037 17 62 0 2 215 BH 5 20.9 1.889 0.252 0.02 9 115 0 2.7 239 23.8 0.603 0.081 0.012 28 191 0 1 215 28.15 1.356 0.212 0.025 11 92 0 0.8 216 52 0.733 0.115 0.011 20 209 0 0.8 392 BH 6 3.25 0.75 0.108 0.017 21 135 0 5.2 225 26.95 0.598 0.1 0.012 23 192 0 1.1 284 4.75 0.893 0.137 0.042 17 55 0 4.2 225 BH 7 22.25 1.168 0.156 0.036 15 64 0 1.7 343 26.75 2.235 0.247 0.021 9 109 0 1.3 353 5.35 1.278 0.162 0.03 14 77 0 2.7 176 8.75 0.521 0.078 0.013 29 177 0 2.3 216 BH 8 20.75 1.46 0.227 0.032 10 72 0 1.8 363 25.15 0.085 0.105 0.016 22 144 0 0.9 206 29.15 0.645 0.079 0.024 29 96 0 0.8 206 4.7 0.658 0.108 0.036 22 64 0 5 274 10.75 0.62 0.08 0.024 29 96 0 2 216 BH 9 20.25 1.523 0.186 0.07 12 32 0 1 186 28.75 0.665 0.102 0.024 23 96 0 0.9 235 43.45 0.7 0.082 0.023 28 100 0 0.5 196
6 Data Extracted from Graphs (attached in Appendix) Depth eo CR RR Cu OCR Gmax ϒ 5 0.8 0.12 0.03 55 4.3 52.946 18.2 10 0.7 0.095 0.035 70 2.9 162.464 19 15 1 0.14 0.02 90 2.9 193.4 19 20 1.6 0.2 0.03 50 1.2 159.626 17.8 25 0.6 0.1 0.025 100 2.5 142.79 17.4 30 0.7 0.09 0.024 150 2.5 208.258 19.5 35 0.7 0.085 0.024 175 2.5 242.66 19.5 40 0.6 0.08 0.022 175 1.3 249.226 19.5 45 0.7 0.08 0.023 175 1.3 166.786 19.5 50 0.7 0.11 0.011 175 1.3 261.78 19.5 55 0.6 0.12 0.01 175 1.3 263.668 19.5 Capacity Calculation DL 8820 LL 16280 V(DL+LL) 25100 V(concrete) 138720 V(given+Conc) 163820 H(.2x(Foundation load x DL)) 11364 M 56820 e 0.346844 D 5 B 34 L 34 B' 33.30631 L' 33.30631 x 1 m 1.5
7 ϒ 19 D 5 sq 1 dq 1.294118 iq 1 bq 1 gq 1 Nq 1 Nc 5.14 q(ult) for DL+LL 597.53 FOS 3 q(allow) 199.18 q(max) Given Vertical load 141.71 q(allow)>q(max) q(ult) for seismic 578.09 FOS2. 5 q(allow) 231.24 q(max) Given Seismic lateral Load 66.847 q(allow)>q(max) Result For Shallow Design 1 My design Satisfies Given Load for a Foundation of 34m X 34m X 5 square footing Settlement Calculation B 34 L 34 cu 73 sc 1.194553 dc 1.058824 ic 0.959047 bc 1 gc 1
8 V 25100 H 11364 cs 0.95 q 21.71280277 B 34 v 0.5 Eu 52794.2 Si 0.009963076 Sc 0.01983263 Settlement 0.029795706 29 mm Plaxis Analysis D E eo CR RR OCR Cr Cc ϒ ϒ' h B+Δz σ'vo Δσ' σ'p log((σ'vo+Δσ')/σ'vo) Sc 5 15.04 0.8 0.120 0.030 4.3 0.054 0.216 18.2 8.4 5 36.5 21 18.84 90.3 0.2781 0.0232 10 45.49 0.7 0.095 0.035 2.9 0.060 0.162 19 9.2 5 41.5 65 14.57 188.5 0.0879 0.0090 15 54.15 1 0.140 0.020 2.9 0.040 0.280 19 9.2 5 46.5 111 11.61 321.9 0.0432 0.0022 20 44.54 1.6 0.200 0.030 1.2 0.078 0.520 17.8 8 5 51.5 154 9.46 184.8 0.0259 0.0015 25 39.70 0.6 0.100 0.025 2.5 0.040 0.160 17.4 7.6 5 56.5 193 7.86 482.5 0.0173 0.0014 30 57.90 0.7 0.090 0.024 2.5 0.041 0.153 19.5 9.7 5 61.5 236.25 6.64 590.6 0.0120 0.0008 35 66.97 0.7 0.085 0.024 2.5 0.041 0.145 19.5 9.7 5 66.5 284.75 5.68 711.9 0.0086 0.0006 40 69.39 0.6 0.080 0.022 1.3 0.035 0.128 19.5 9.7 5 71.5 333.25 4.91 433.2 0.0064 0.0004 45 45.70 0.7 0.080 0.023 1.3 0.039 0.136 19.5 9.7 5 76.5 381.75 4.29 496.3 0.0049 0.0003 50 70.68 0.7 0.110 0.011 1.3 0.019 0.187 19.5 9.7 5 81.5 430.25 3.78 559.3 0.0038 0.0001 55 71.19 0.6 0.120 0.010 1.3 0.016 0.192 19.5 9.7 5 86.5 478.75 3.35 622.4 0.0030 9E-05 Total Sc 0.0198
9 Data Used in Plaxis Depth ϒ Cu E 5 18.2 55 15.037 10 19 70 45.4894 15 19 90 54.1518 20 17.8 50 44.5374 25 17.4 100 39.6958 30 19.5 150 57.8954 35 19.5 175 66.973 40 19.5 175 69.3864 45 19.5 175 45.6996 50 19.5 175 70.6802 55 19.5 175 71.1902
10 Result For Shallow Design 1 My design of 34 X 34 X 5 m footing settles for 29 mm and from Plaxis the value is 29.1 mm Shallow design 2 Shallow foundation option resting on improved soil (using the soil mixing technique) between depths5.0 and 25.0 m below grade. In this option, the cement‐soil mixing technique with result in minimum undrained shear strength of the improved soil, Su = 100 kPa. The soil improvement technique will also reduce the compression ratio by at least 50%, i.e., CR improved soil = CR native soil/2 Capacity Calculation
11 D 5 B 24 L 24 B' 22.34557 L' 22.34557 x 1 m 1.5 Nq 1 Nc 5.14 DL 8820 LL 16280 V(DL+LL) 25100 V(concrete) 69120 V(given+Conc) 94220 H 15588 M 77940 e 0.827213 ϒ 19 D 5 sq 1 dq 1.416667 iq 1 bq 1 gq 1 cu 100 sc 1.194553 dc 1.083333 ic 0.908896 bc 1 gc 1
12 q(ult) for DL+LL 799.75 FOS 3 q(allow) 266.5833 q(max)Give n Vertical load 163.5764 q(allow) >q(max) q(ult) for seismic 739.1509 FOS2.5 q(allow) 295.6604 q(max)Give n Seismic lateral Load 129.9 q(allow) >q(max) Settlement Calculation cs 0.95 q 43.57639 B 24 v 0.5 Eu 52794.2 Si 0.014114 Sc 0.015416 Settlement 0.02953 29 mm Depth E eo CR RR OCR Cr Cc ϒ ϒ' h B+Δz σ'vo Δσ' σ'p log((σ'vo+Δσ')/σ'vo) Sc 5 15.037 0.8 0.06 0.015 4.3 0.027 0.108 18.2 8.4 5 26.5 21 35.74225703 90.3 0.431687312 0.017986971 10 45.4894 0.7 0.0475 0.0175 2.9 0.02975 0.08075 19 9.2 5 31.5 65 25.29604434 188.5 0.142755369 0.007347703 15 54.1518 1 0.07 0.01 2.9 0.02 0.14 19 9.2 5 36.5 111 18.84030775 321.9 0.068086557 0.001702164 20 44.5374 1.6 0.1 0.015 1.2 0.039 0.26 17.8 8 5 41.5 154 14.57395848 184.8 0.039269764 0.001132782 25 39.6958 0.6 0.05 0.0125 2.5 0.02 0.08 17.4 7.6 5 46.5 193 11.60827841 482.5 0.025365892 0.000990855 30 57.8954 0.7 0.045 0.012 2.5 0.0204 0.0765 19.5 9.7 5 51.5 236.25 9.463662928 590.625 0.017057489 0.000602029 35 66.973 0.7 0.0425 0.012 2.5 0.0204 0.07225 19.5 9.7 5 56.5 284.75 7.862792701 711.875 0.011829576 0.000417514 40 69.3864 0.6 0.04 0.011 1.3 0.0176 0.064 19.5 9.7 5 61.5 333.25 6.636261485 433.225 0.008563452 0.000294369 45 45.6996 0.7 0.04 0.0115 1.3 0.01955 0.068 19.5 9.7 5 66.5 381.75 5.675843745 496.275 0.006409542 0.000216793 50 70.6802 0.7 0.055 0.0055 1.3 0.00935 0.0935 19.5 9.7 5 71.5 430.25 4.909775539 559.325 0.004927865 7.97155E-05 55 71.1902 0.6 0.06 0.005 1.3 0.008 0.096 19.5 9.7 5 76.5 478.75 4.288948695 622.375 0.003873363 6.05213E-05 Total Sc 0.015415709
13 Plaxis Analysis Data Used Depth ϒ Cu E 5 18.2 100 15.037 10 19 100 45.4894 15 19 100 54.1518 20 17.8 100 44.5374 25 17.4 100 39.6958 30 19.5 150 57.8954 35 19.5 175 66.973 40 19.5 175 69.3864 45 19.5 175 45.6996 50 19.5 175 70.6802 55 19.5 175 71.1902
14 Result For Shallow Design 1 My design of 24 X 24 X 5 m footing settles for 29 mm and from Plaxis the value is 28 mm
15 Deep Design Capacity Calculation and Pile parameters Depth Cu Δz α Qs 2 15 2 1 141.372 7 55 5 0.9 1166.319 12 70 5 0.3 494.802 16 90 4 0.9 1526.818 21 50 5 0.25 294.525 27 100 6 0.25 706.86 32 150 5 0.25 883.575 40 175 8 0.3 1979.208 45 175 5 0.3 1237.005 50 175 5 0.3 1237.005 55 175 5 0.3 1237.005 V 25100 FS 3 Qu group 75300 G 0.7 n 23.90295 25 pcs Qgroup (design) 26252 Qu (design) 78755.99 L 25 d 0.6 Le 25 Ab 0.282744 Nc 6 Cub 100 Circumfurence 4.7124 Qb 169.6464 Qs 4330.696 Qult 4500.342 Qsingle 1500.114
16 Result For Given Calculation my Engineering calculation and recommends to have 25 pieces of 25 meter concretes bored piles of .6m diameter Single Pile Settlement Calculation L 25 d 0.6 Cs 0.058884 Cb 0.03 fb 2119 Qb 296.8812 Qs 4330.696 FOS 3 cub 175 Nc 9 σvb 544 Qba 98.9604 Qsa 1443.565 αs 0.67 Ap 0.282744 Ep 30000000
17 Sss 0.001605 Ssb 0.001335 Sp 0.003142 Ssingle 0.006082 6 mm Group Pile Settlement Calculation dc 4.4 L 25 n 25 Ap 0.2827 Ep 30000000 b' 9 l' 9 Es 198911.4 Qa 1004 Eeq 3319196 S 0.0300295 30 mm
18 n 25 w 0.5 Rs 5 SG 0.03041 30 mm Lateral Capacity Calculation Solving this two equation we get a quadric equation and from there I got my Pile capacity of 451.39 Kpa for single Pile and 11284.7kpa for group Pile. My Myeild was greater than Mmax so I used Long pile fixed head formula, though I have a short pile . I 0.00636 S 0.021 fy 30000 fr 0.6 M yield 378
19 P 293.112 x f f 1.54 P 451.39 PG 11284.75 Lateral Deflection Calculation yg = HfyF H 11364 L 25 d 0.6 fy 30000000 Ep 24647515.09 Es 1989114 K 12.39120286 fyh 6.92424E-07 fθH 9.89827E-07 fθM 3.40959E-06 fyF 4.0507E-07 yg 0.004603 4.6 mm
20 8. Results of All Design Criteria 1. Shallow Foundation Type 1 Design 34m X 34m X 5m concrete square footing. Capacity vertical load q allowable =199.1757 kpa q max =141.71 kpa Capacity for seismic load q allowable = 217.4114224 kpa q max = 173.5764706 kpa Settlement 29 mm 2. Shallow Foundation Type 2 Design 24m X 24m X 5m concrete square footing. Capacity for vertical load q allowable = 266.5833333 kpa q max = 163.5763889 kpa Capacity for seismic load q allowable = 295.660371 kpa q max = 129.9 kpa Settlement 29mm
21 3. Deep Foundation Type 1 Design: 25 meter deep, 0.6 meter diameter 25 pcs of concrete pile bored in a distance of 1.8 meter Capacity q single = 1542.5256 kpa q Group = 26994.198 kpa Settlement Ssingle =6 mm Sgroup =30 mm Lateral Capacity q single = 451.39 kpa q group = 11284.75 kpa Lateral Deflection 4.6 mm 9. Recommended Design for Client The transfer of loads from deep foundations to the soil is different from that of shallow foundations. Shallow foundations primarily transfer the load to the soil via bearing pressure. Deep foundations also transfer the load via friction along the length (or depth) of the foundation, called skin friction. The force that remains at the bottom of the deep foundation is transferred to the soil by bearing pressure. Shallow foundations, often called footings, are usually embedded about few meters into soil ( in this case 5 meters) One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the soil or bedrock. Another common type of shallow foundation is the slab-on- grade foundation where the weight of the building is transferred to the soil through a concrete slab placed at the surface. Slab-on-grade foundations can be reinforced mat slabs, which range from 30 cm to several meters thick, depending on the size of the building, or post-tensioned slabs, which are typically at least 20 cm for houses, and thicker for heavier structures. A deep foundation is used to transfer the load of a structure down through the upper weak layer of
22 topsoil to the stronger layer of subsoil below. There are different types of deep footings including impact driven piles, drilled shafts, caissons, helical piles, geo-piers and earth stabilized columns. The naming conventions for different types of footings vary between different engineers. Historically, piles were wood, later steel, reinforced concrete, and pre-tensioned concrete. In this case my engineering recommendation is Deep foundation Type 1.If I have a chance to install shallow foundation over a deep foundation I would definitely go for that always because deep foundations are complicated to install and it is expensive than shallow foundation. In my design I have 25 piles means I have to make 25 bore hole and I have to bore those until 25 meters of depth with 1.8 meters of spacing, so for avoiding complicated design and cost I would prefer Shallow foundation Now I have 2 options for shallow foundation. One is in improved soil and my designed footing is 24 X 24 X 5 which is much lesser than the designed footing of 34 X 34 X 5 in natural soil. So volume of concrete is more in shallow foundation design 1 but I would still go for design 1 because improving soil up to 25 meters would be so costly and the installation procedure would take much time because I have to excavate soil up to a fair amount of depth of 25 meters. So counting time and money as well design complicacy I would recommend my client to go for Shallow foundation design type 1.
23 10. Appendix Tables Table 1
24 Table 2 Table 3
25 Table 4
26 Table 5
27 Table 6 Graphs Graph 1
28 Graph 2 Graph 3
29 Graph 4 11. References 1. Lecture Notes of M. Hesham El Naggar, Ph.D., P. Eng., MASCE, FEIC,Professor and Research Director,Geotechnical Research Centre 2. soilseries.sc.egov.usda.gov/OSD_Docs/C/COLUMBIA.html
30 3. http://en.wikipedia.org/wiki/Deep_foundation 4. Simplified Design of Building Foundations, 2nd Edition by James Ambrose (Author) 5. Building Foundations of Scientific Understanding: A Science Curriculum for K-2 by Bernard J. Nebel (Author) 6. Foundation Engineering P. C. VARGHESE 7. Foundation Engineering Handbook by Robert Day McGraw Hill Professional, Dec 12, 2005

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Term Project Paper on Design of Shallow and Deep Foundation for a cement plant in Columbia

  • 1. 1 Term Project Paper on Design of Shallow and Deep Foundation for a cement plant in Columbia Submitted by J M RAKIBUL HASAN (250821180) 24th April 2015 Graduate Program: Foundation Engineering Professor M. Hesham El Naggar The School of Civil and Environmental Engineering The University of Western Ontario London, Ontario, Canada An Assignment submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Civil and Environmental Engineering
  • 2. 2 Content 1. Project Background………………………………………………………………………….1 2. Project Description…………………………………………………………………………..1 3. Soil profile of Cement Plant…………………………………………………………………1 4. Design Conditions……………………………………………………………………………1 5. Design Expectations………………………………………………………………………….2 6. Scope of work………………………………………………………………………………...2 7. Design Criteria……………………………………………………………………………….2 Shallow Design 1………………………………………………………………………..3 Capacity Calculation…………………………………………………………...4 Settlement Calculation…………………………………………………………5 Plaxis Analysis…………………………………………………………………..7 Shallow design 2………………………………………………………………………...7 Capacity Calculation……………………………………………………………7 Settlement Calculation………………………………………………………….10 Plaxis Analysis…………………………………………………………………..11 Deep Design……………………………………………………………………………..13 Capacity Calculation and Pile parameters…………………………………....13 Single Pile Settlement Calculation……………………………………………..14 Group Pile Settlement Calculation…………………………………………….15 Lateral Capacity Calculation…………………………………………………..16 Lateral Deflection Calculation…………………………………………………17 8. Results of All Design Criteria……………………………………………………………….18 9. Recommended Design for Client…………………………………………………………....19 10. Appendix…………………………………………………………………………………….21 11. References…………………………………………………………………………………...27
  • 3. 3 1. Project Background My given Project work is to design shallow and deep foundation for a Cement Plant. A cement plant is a structure for grinding, mixing and processing Cement of various kinds for constructional purpose. From a foundation engineering point of view the loading pattern of a cement plant on existing foundation is not constant because after grinding and processing the cement materials are taken away from plant and the amounts are not always the same. So the live load on existing ground level may change rapidly but I have to design a foundation for the maximum live load from a cement plan. 2. Project Description My Project structure is Situated in Columbia, a country situated in the northwest of South America, The soil between depths of 8 and 25 inches, (20 to 64 cm) is moist in some or all parts from late October to late May or June and is dry in all parts the remainder of the year, unless irrigated. The 10 to 40 inches, (25 to 102 cm) particle-size control section is stratified fine sandy loam, very fine sandy loam, silt loam, loam, loamy sand, loamy fine sand, fine sand or sand and averages 10 to 18 percent clay, when mixed, and has greater than 15 percent fine sand or coarser. Up to 35 percent gravel may occur below a depth of 40 inches, (102 cm). Redoximorphic features occur between 10 and 48 inches, (25 to 122 cm). Content of organic matter decreases irregularly with depth. 3. Soil profile of Cement Plant A geotechnical investigation was conducted to determine the soil parameters required for the design, which 5 boreholes, BH‐5 to BH9 that extended to 60.0 m below ground surface. The site generally consists of around 1.5 m of fill, followed by natural (native) cohesive (sandy silt clay, sandy clay, lean clay, fat clay, silty clay, and clayey silt). Undisturbed soil samples were retrieved using thin walled Shelby tubes and were used to determine the undrained shear strength and deformation characteristics. In addition, geophysical study was conducted to determine the dynamic soil properties of the site soils. The results from the field and laboratory tests are provided in Tables 1‐4 of Appendix. 4. Design Conditions It is required to design a foundation system to support a cement mill. The total static (dead) load of the mill and associated equipment is 8,820 kN and the total operating load (dead + live loads) is 25,100 kN. The top of concrete of the proposed foundation will be at the existing ground elevation and the thickness of the foundation will be 5.0 m. To accommodate the mill and the associated equipment, the foundation (or pile cap) has to be square with minimum side length of
  • 4. 4 20.0 m. The maximum (total) settlement allowed is 30 mm. The plant is located in a seismic zone characterized by peak ground acceleration of 0.2 g. 5. Design Expectations Different foundation options are considered for supporting the proposed mill, including: 1. Shallow Foundation 1) Shallow foundation resting on the native soil at depth 5.0 m below existing grade. In this option, the design soil parameters that should be used in the design are based on the measured properties presented in Tables 1‐4 and Figures 1‐4; 2) Shallow foundation option resting on improved soil (using the soil mixing technique) between depths5.0 and 25.0 m below grade. In this option, the cement‐soil mixing technique with result in minimum undrained shear strength of the improved soil, Su = 100 kPa. The soil improvement technique will also reduce the compression ratio by at least 50%, i.e., CR improved soil = CR native soil/2; 2. Deep foundation 1) The preferred deep foundation option is drilled cast in place piles. The available equipment allows the construction of piles 0.60, 0.90, 1.20 and 1.50m diameter. 6. Scope of work This is a practical problem for given loads and conditions. So different foundation system can be compared to find the best foundation option for a client. Engineering Recommendation and discussions on designed length, width, depth and other parameters of concrete foundation can really pave the way of an economical solution 7. Design Criteria Shallow Deep
  • 5. 5 Shallow Design 1 1) Shallow foundation resting on the native soil at depth 5.0 m below existing grade. In this option, the design soil parameters that should be used in the design are based on the measured properties presented in Tables 1‐4 and Figures 1‐4; Given Data Depth eO CR RR m Mr j OCR Pc 5.55 0.404 0.078 0.014 29 164 0 5 343 9.9 0.896 0.132 0.037 17 62 0 2 215 BH 5 20.9 1.889 0.252 0.02 9 115 0 2.7 239 23.8 0.603 0.081 0.012 28 191 0 1 215 28.15 1.356 0.212 0.025 11 92 0 0.8 216 52 0.733 0.115 0.011 20 209 0 0.8 392 BH 6 3.25 0.75 0.108 0.017 21 135 0 5.2 225 26.95 0.598 0.1 0.012 23 192 0 1.1 284 4.75 0.893 0.137 0.042 17 55 0 4.2 225 BH 7 22.25 1.168 0.156 0.036 15 64 0 1.7 343 26.75 2.235 0.247 0.021 9 109 0 1.3 353 5.35 1.278 0.162 0.03 14 77 0 2.7 176 8.75 0.521 0.078 0.013 29 177 0 2.3 216 BH 8 20.75 1.46 0.227 0.032 10 72 0 1.8 363 25.15 0.085 0.105 0.016 22 144 0 0.9 206 29.15 0.645 0.079 0.024 29 96 0 0.8 206 4.7 0.658 0.108 0.036 22 64 0 5 274 10.75 0.62 0.08 0.024 29 96 0 2 216 BH 9 20.25 1.523 0.186 0.07 12 32 0 1 186 28.75 0.665 0.102 0.024 23 96 0 0.9 235 43.45 0.7 0.082 0.023 28 100 0 0.5 196
  • 6. 6 Data Extracted from Graphs (attached in Appendix) Depth eo CR RR Cu OCR Gmax ϒ 5 0.8 0.12 0.03 55 4.3 52.946 18.2 10 0.7 0.095 0.035 70 2.9 162.464 19 15 1 0.14 0.02 90 2.9 193.4 19 20 1.6 0.2 0.03 50 1.2 159.626 17.8 25 0.6 0.1 0.025 100 2.5 142.79 17.4 30 0.7 0.09 0.024 150 2.5 208.258 19.5 35 0.7 0.085 0.024 175 2.5 242.66 19.5 40 0.6 0.08 0.022 175 1.3 249.226 19.5 45 0.7 0.08 0.023 175 1.3 166.786 19.5 50 0.7 0.11 0.011 175 1.3 261.78 19.5 55 0.6 0.12 0.01 175 1.3 263.668 19.5 Capacity Calculation DL 8820 LL 16280 V(DL+LL) 25100 V(concrete) 138720 V(given+Conc) 163820 H(.2x(Foundation load x DL)) 11364 M 56820 e 0.346844 D 5 B 34 L 34 B' 33.30631 L' 33.30631 x 1 m 1.5
  • 7. 7 ϒ 19 D 5 sq 1 dq 1.294118 iq 1 bq 1 gq 1 Nq 1 Nc 5.14 q(ult) for DL+LL 597.53 FOS 3 q(allow) 199.18 q(max) Given Vertical load 141.71 q(allow)>q(max) q(ult) for seismic 578.09 FOS2. 5 q(allow) 231.24 q(max) Given Seismic lateral Load 66.847 q(allow)>q(max) Result For Shallow Design 1 My design Satisfies Given Load for a Foundation of 34m X 34m X 5 square footing Settlement Calculation B 34 L 34 cu 73 sc 1.194553 dc 1.058824 ic 0.959047 bc 1 gc 1
  • 8. 8 V 25100 H 11364 cs 0.95 q 21.71280277 B 34 v 0.5 Eu 52794.2 Si 0.009963076 Sc 0.01983263 Settlement 0.029795706 29 mm Plaxis Analysis D E eo CR RR OCR Cr Cc ϒ ϒ' h B+Δz σ'vo Δσ' σ'p log((σ'vo+Δσ')/σ'vo) Sc 5 15.04 0.8 0.120 0.030 4.3 0.054 0.216 18.2 8.4 5 36.5 21 18.84 90.3 0.2781 0.0232 10 45.49 0.7 0.095 0.035 2.9 0.060 0.162 19 9.2 5 41.5 65 14.57 188.5 0.0879 0.0090 15 54.15 1 0.140 0.020 2.9 0.040 0.280 19 9.2 5 46.5 111 11.61 321.9 0.0432 0.0022 20 44.54 1.6 0.200 0.030 1.2 0.078 0.520 17.8 8 5 51.5 154 9.46 184.8 0.0259 0.0015 25 39.70 0.6 0.100 0.025 2.5 0.040 0.160 17.4 7.6 5 56.5 193 7.86 482.5 0.0173 0.0014 30 57.90 0.7 0.090 0.024 2.5 0.041 0.153 19.5 9.7 5 61.5 236.25 6.64 590.6 0.0120 0.0008 35 66.97 0.7 0.085 0.024 2.5 0.041 0.145 19.5 9.7 5 66.5 284.75 5.68 711.9 0.0086 0.0006 40 69.39 0.6 0.080 0.022 1.3 0.035 0.128 19.5 9.7 5 71.5 333.25 4.91 433.2 0.0064 0.0004 45 45.70 0.7 0.080 0.023 1.3 0.039 0.136 19.5 9.7 5 76.5 381.75 4.29 496.3 0.0049 0.0003 50 70.68 0.7 0.110 0.011 1.3 0.019 0.187 19.5 9.7 5 81.5 430.25 3.78 559.3 0.0038 0.0001 55 71.19 0.6 0.120 0.010 1.3 0.016 0.192 19.5 9.7 5 86.5 478.75 3.35 622.4 0.0030 9E-05 Total Sc 0.0198
  • 9. 9 Data Used in Plaxis Depth ϒ Cu E 5 18.2 55 15.037 10 19 70 45.4894 15 19 90 54.1518 20 17.8 50 44.5374 25 17.4 100 39.6958 30 19.5 150 57.8954 35 19.5 175 66.973 40 19.5 175 69.3864 45 19.5 175 45.6996 50 19.5 175 70.6802 55 19.5 175 71.1902
  • 10. 10 Result For Shallow Design 1 My design of 34 X 34 X 5 m footing settles for 29 mm and from Plaxis the value is 29.1 mm Shallow design 2 Shallow foundation option resting on improved soil (using the soil mixing technique) between depths5.0 and 25.0 m below grade. In this option, the cement‐soil mixing technique with result in minimum undrained shear strength of the improved soil, Su = 100 kPa. The soil improvement technique will also reduce the compression ratio by at least 50%, i.e., CR improved soil = CR native soil/2 Capacity Calculation
  • 11. 11 D 5 B 24 L 24 B' 22.34557 L' 22.34557 x 1 m 1.5 Nq 1 Nc 5.14 DL 8820 LL 16280 V(DL+LL) 25100 V(concrete) 69120 V(given+Conc) 94220 H 15588 M 77940 e 0.827213 ϒ 19 D 5 sq 1 dq 1.416667 iq 1 bq 1 gq 1 cu 100 sc 1.194553 dc 1.083333 ic 0.908896 bc 1 gc 1
  • 12. 12 q(ult) for DL+LL 799.75 FOS 3 q(allow) 266.5833 q(max)Give n Vertical load 163.5764 q(allow) >q(max) q(ult) for seismic 739.1509 FOS2.5 q(allow) 295.6604 q(max)Give n Seismic lateral Load 129.9 q(allow) >q(max) Settlement Calculation cs 0.95 q 43.57639 B 24 v 0.5 Eu 52794.2 Si 0.014114 Sc 0.015416 Settlement 0.02953 29 mm Depth E eo CR RR OCR Cr Cc ϒ ϒ' h B+Δz σ'vo Δσ' σ'p log((σ'vo+Δσ')/σ'vo) Sc 5 15.037 0.8 0.06 0.015 4.3 0.027 0.108 18.2 8.4 5 26.5 21 35.74225703 90.3 0.431687312 0.017986971 10 45.4894 0.7 0.0475 0.0175 2.9 0.02975 0.08075 19 9.2 5 31.5 65 25.29604434 188.5 0.142755369 0.007347703 15 54.1518 1 0.07 0.01 2.9 0.02 0.14 19 9.2 5 36.5 111 18.84030775 321.9 0.068086557 0.001702164 20 44.5374 1.6 0.1 0.015 1.2 0.039 0.26 17.8 8 5 41.5 154 14.57395848 184.8 0.039269764 0.001132782 25 39.6958 0.6 0.05 0.0125 2.5 0.02 0.08 17.4 7.6 5 46.5 193 11.60827841 482.5 0.025365892 0.000990855 30 57.8954 0.7 0.045 0.012 2.5 0.0204 0.0765 19.5 9.7 5 51.5 236.25 9.463662928 590.625 0.017057489 0.000602029 35 66.973 0.7 0.0425 0.012 2.5 0.0204 0.07225 19.5 9.7 5 56.5 284.75 7.862792701 711.875 0.011829576 0.000417514 40 69.3864 0.6 0.04 0.011 1.3 0.0176 0.064 19.5 9.7 5 61.5 333.25 6.636261485 433.225 0.008563452 0.000294369 45 45.6996 0.7 0.04 0.0115 1.3 0.01955 0.068 19.5 9.7 5 66.5 381.75 5.675843745 496.275 0.006409542 0.000216793 50 70.6802 0.7 0.055 0.0055 1.3 0.00935 0.0935 19.5 9.7 5 71.5 430.25 4.909775539 559.325 0.004927865 7.97155E-05 55 71.1902 0.6 0.06 0.005 1.3 0.008 0.096 19.5 9.7 5 76.5 478.75 4.288948695 622.375 0.003873363 6.05213E-05 Total Sc 0.015415709
  • 13. 13 Plaxis Analysis Data Used Depth ϒ Cu E 5 18.2 100 15.037 10 19 100 45.4894 15 19 100 54.1518 20 17.8 100 44.5374 25 17.4 100 39.6958 30 19.5 150 57.8954 35 19.5 175 66.973 40 19.5 175 69.3864 45 19.5 175 45.6996 50 19.5 175 70.6802 55 19.5 175 71.1902
  • 14. 14 Result For Shallow Design 1 My design of 24 X 24 X 5 m footing settles for 29 mm and from Plaxis the value is 28 mm
  • 15. 15 Deep Design Capacity Calculation and Pile parameters Depth Cu Δz α Qs 2 15 2 1 141.372 7 55 5 0.9 1166.319 12 70 5 0.3 494.802 16 90 4 0.9 1526.818 21 50 5 0.25 294.525 27 100 6 0.25 706.86 32 150 5 0.25 883.575 40 175 8 0.3 1979.208 45 175 5 0.3 1237.005 50 175 5 0.3 1237.005 55 175 5 0.3 1237.005 V 25100 FS 3 Qu group 75300 G 0.7 n 23.90295 25 pcs Qgroup (design) 26252 Qu (design) 78755.99 L 25 d 0.6 Le 25 Ab 0.282744 Nc 6 Cub 100 Circumfurence 4.7124 Qb 169.6464 Qs 4330.696 Qult 4500.342 Qsingle 1500.114
  • 16. 16 Result For Given Calculation my Engineering calculation and recommends to have 25 pieces of 25 meter concretes bored piles of .6m diameter Single Pile Settlement Calculation L 25 d 0.6 Cs 0.058884 Cb 0.03 fb 2119 Qb 296.8812 Qs 4330.696 FOS 3 cub 175 Nc 9 σvb 544 Qba 98.9604 Qsa 1443.565 αs 0.67 Ap 0.282744 Ep 30000000
  • 17. 17 Sss 0.001605 Ssb 0.001335 Sp 0.003142 Ssingle 0.006082 6 mm Group Pile Settlement Calculation dc 4.4 L 25 n 25 Ap 0.2827 Ep 30000000 b' 9 l' 9 Es 198911.4 Qa 1004 Eeq 3319196 S 0.0300295 30 mm
  • 18. 18 n 25 w 0.5 Rs 5 SG 0.03041 30 mm Lateral Capacity Calculation Solving this two equation we get a quadric equation and from there I got my Pile capacity of 451.39 Kpa for single Pile and 11284.7kpa for group Pile. My Myeild was greater than Mmax so I used Long pile fixed head formula, though I have a short pile . I 0.00636 S 0.021 fy 30000 fr 0.6 M yield 378
  • 19. 19 P 293.112 x f f 1.54 P 451.39 PG 11284.75 Lateral Deflection Calculation yg = HfyF H 11364 L 25 d 0.6 fy 30000000 Ep 24647515.09 Es 1989114 K 12.39120286 fyh 6.92424E-07 fθH 9.89827E-07 fθM 3.40959E-06 fyF 4.0507E-07 yg 0.004603 4.6 mm
  • 20. 20 8. Results of All Design Criteria 1. Shallow Foundation Type 1 Design 34m X 34m X 5m concrete square footing. Capacity vertical load q allowable =199.1757 kpa q max =141.71 kpa Capacity for seismic load q allowable = 217.4114224 kpa q max = 173.5764706 kpa Settlement 29 mm 2. Shallow Foundation Type 2 Design 24m X 24m X 5m concrete square footing. Capacity for vertical load q allowable = 266.5833333 kpa q max = 163.5763889 kpa Capacity for seismic load q allowable = 295.660371 kpa q max = 129.9 kpa Settlement 29mm
  • 21. 21 3. Deep Foundation Type 1 Design: 25 meter deep, 0.6 meter diameter 25 pcs of concrete pile bored in a distance of 1.8 meter Capacity q single = 1542.5256 kpa q Group = 26994.198 kpa Settlement Ssingle =6 mm Sgroup =30 mm Lateral Capacity q single = 451.39 kpa q group = 11284.75 kpa Lateral Deflection 4.6 mm 9. Recommended Design for Client The transfer of loads from deep foundations to the soil is different from that of shallow foundations. Shallow foundations primarily transfer the load to the soil via bearing pressure. Deep foundations also transfer the load via friction along the length (or depth) of the foundation, called skin friction. The force that remains at the bottom of the deep foundation is transferred to the soil by bearing pressure. Shallow foundations, often called footings, are usually embedded about few meters into soil ( in this case 5 meters) One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the soil or bedrock. Another common type of shallow foundation is the slab-on- grade foundation where the weight of the building is transferred to the soil through a concrete slab placed at the surface. Slab-on-grade foundations can be reinforced mat slabs, which range from 30 cm to several meters thick, depending on the size of the building, or post-tensioned slabs, which are typically at least 20 cm for houses, and thicker for heavier structures. A deep foundation is used to transfer the load of a structure down through the upper weak layer of
  • 22. 22 topsoil to the stronger layer of subsoil below. There are different types of deep footings including impact driven piles, drilled shafts, caissons, helical piles, geo-piers and earth stabilized columns. The naming conventions for different types of footings vary between different engineers. Historically, piles were wood, later steel, reinforced concrete, and pre-tensioned concrete. In this case my engineering recommendation is Deep foundation Type 1.If I have a chance to install shallow foundation over a deep foundation I would definitely go for that always because deep foundations are complicated to install and it is expensive than shallow foundation. In my design I have 25 piles means I have to make 25 bore hole and I have to bore those until 25 meters of depth with 1.8 meters of spacing, so for avoiding complicated design and cost I would prefer Shallow foundation Now I have 2 options for shallow foundation. One is in improved soil and my designed footing is 24 X 24 X 5 which is much lesser than the designed footing of 34 X 34 X 5 in natural soil. So volume of concrete is more in shallow foundation design 1 but I would still go for design 1 because improving soil up to 25 meters would be so costly and the installation procedure would take much time because I have to excavate soil up to a fair amount of depth of 25 meters. So counting time and money as well design complicacy I would recommend my client to go for Shallow foundation design type 1.
  • 29. 29 Graph 4 11. References 1. Lecture Notes of M. Hesham El Naggar, Ph.D., P. Eng., MASCE, FEIC,Professor and Research Director,Geotechnical Research Centre 2. soilseries.sc.egov.usda.gov/OSD_Docs/C/COLUMBIA.html
  • 30. 30 3. http://en.wikipedia.org/wiki/Deep_foundation 4. Simplified Design of Building Foundations, 2nd Edition by James Ambrose (Author) 5. Building Foundations of Scientific Understanding: A Science Curriculum for K-2 by Bernard J. Nebel (Author) 6. Foundation Engineering P. C. VARGHESE 7. Foundation Engineering Handbook by Robert Day McGraw Hill Professional, Dec 12, 2005