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Capacity of steel h-pile and biased factor for different nominal capacities including finite element analysis

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Title:
Capacity of steel h-pile and biased factor for different nominal capacities including finite element analysis
Creator:
Taya, Marwah
Place of Publication:
Denver, CO
Publisher:
University of Colorado Denver
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Language:
English

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Degree:
Master's ( Master of science)
Degree Grantor:
University of Colorado Denver
Degree Divisions:
Department of Civil Engineering, CU Denver
Degree Disciplines:
Civil engineering
Committee Chair:
Chang, Nien-Yin

Notes

Abstract:
This thesis is based on a project that I participated in and was carried out in the Geotechnical/Structural Laboratory at the University of Colorado Denver. The objective of this thesis is to analyze the load transfer mechanism between piles and supporting soils in terms of the settlement versus vertical load relationship. The study includes a literature review of different methods to calculate the nominal capacity in cohesion and cohesionless soil including α Tomlinson, α API, λ-Method, Nordlund β-Method, and field testing. This research used to 5 W4x13 steel piles drive into a stiff Leyden clay in pile model vertical load tests in a stiff steel Tiger Cage (4’ x 6’x 12’). Four piles are considered production piles and one test pile, Pile #5. The #5 Test Pile is fully instrumented and it load transfer mechanism monitored with strain gauges. An in-house pneumatic pile driver was designed, fabricated, and successfully tested for the pile driving in T-cage with 6-ft of compacted stiff Leyden clay from Golden, Colorado. The following tasks were performed: determination of properties for the Leyden clay; strain gage installation for the measurement of end bearing capacity and the total capacity. Driving five piles spaced 2-ft on-center (one SLT test pile and four production piles as reaction piles). evaluating nominal capacity using various design methods. Finally, the measured static load test capacity was correlated with various nominal capacities via biased factors. And test the survivability of the instrument (strain gauges) whether it can be implemented in the field. This study used the Finite Element Analysis to analyze the response of a pile driven in a clay soil under the effect of static load testing, analyzed bearing capacity and settlement in the H-pile of W4X13 with SSI3D program, and comparing the result with static load test and the calculated bearing capacity using α- method.

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University of Colorado Denver
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Auraria Library
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Copyright Marwah Taya. Permission granted to University of Colorado Denver to digitize and display this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.

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CAPACITY OF STEEL H PILE AND BIASED FACTO R FOR DIFFERENT NOMINAL CAPACITIES INCLUDING FINITE ELEMENT ANALYSIS By MARWAH TAYA B.S. Civil Engineering, U niversity of Technology Iraq/Baghdad , 2010 A thesis submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of requirement s for the Civil Engineering 2018

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ii ACKNOWLEDGMENTS I am indebted, first and foremost, to my advisor Dr. Nien Yin Chang for providing me the support and guidance, and for the advices during my study and research for the thesis. And would like to thank also Dr. Hien Nghiem and for Dr. Trever Wang for serving on the final examination committee. I would like to express my special thanks to my husband for his sacrifice, assistance, and encouraged me to pursue my dreams and finish my research . I also thank my parents, my brother s and sisters for their support and all of my friends who helped me in many ways to accomplish this research.

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i Marwah Taya (Masters, Civil Engineering) Capacity o f Steel H Pile and Biased Factor s from using Different Nominal Capacit ies using Different Nominal Capacity Evaluation Methods, Including Finite Element Analysis Thesis directed by Professor Nien Yin Chang Abstract This thesis is based on a project that I participated in and was carried out in the Geotechnical/Structural Laboratory at the University of Colorado Denver. The objective of this thesis is to analyze the load transfer mechanism between piles and supporting soils in terms of the settlement versus vertical load relationship. The study i ncludes a literature review of different methods to calculate Method, Nordlund Method, and field testing. This research used to 5 W4x13 steel piles driv e in to a stiff Leyden clay in pile m odel vertical load tests in a stiff steel . Four piles are considered production piles and one test pile, Pile #5. The #5 Test Pil e is fully instrumented and it load transfer mechanism monitored with s train gauges. An in house pneumatic pile driver was designed, fabricated, and successfully tested for the pile driving in T cage with 6 ft of compacted stiff Leyden clay from Golden, Co lorado. The following tasks were performed: determination of properties for the Leyden clay; strain gage installation for the measurement of end bearing capacity and the total capacity. Driving five piles spaced 2 ft on center (one SLT test pile and four p roduction piles as reaction piles). evaluating nominal capacity using various design methods. Finally, the measured static load test capacity was correlated with various nominal capacities via biased factors. And test the survivability of the instrument (s train gauges) whether it can be implemented in the field. This study used the Finite Element Analysis to analyze the response of a pile driven in a clay soil under the effect of static load testing, analyzed bearing capacity and settlement in the H pile of W4X13 with method. The form and content of this abstract are approved. I recommend its publication. Approved: Nien Yin Chang

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ii TABLE OF CONTENT FIGURES ................................ ................................ ................................ ................................ .................... iv TABLES ................................ ................................ ................................ ................................ ..................... vii 1. Introduction ................................ ................................ ................................ ................................ ............... 1 1.1 Foundation types ................................ ................................ ................................ ................................ . 1 1.2 Pile types and H piles and Pipe piles are used in Colorado ................................ ................................ 3 1.2.1 Pile types ................................ ................................ ................................ ................................ ...... 3 1.2.2 H pile and pipe piles Colorado uses ................................ ................................ ............................. 7 1.2.3 Driven H piles advantages and disadvantages ................................ ................................ ............. 8 1.3 Load and Resistance factor designs ................................ ................................ ................................ ..... 9 1.3.1 History and reasons for Load and Resistance Factor Design (LRFD) ................................ ......... 9 1.3.2 Advantages and Disadvantages of using (LRFD) ................................ ................................ ...... 10 1.4 M odel test of driven H pile tests ................................ ................................ ................................ ....... 11 1.5 Study Objective ................................ ................................ ................................ ................................ . 11 2. Literature review on nominal capacity calculation for H piles in sand and clay ................................ .... 12 2.1 Pile capacity theories ................................ ................................ ................................ ......................... 12 2.2 Side resistance in cohesive soil ................................ ................................ ................................ ......... 14 Tomlinson Method ................................ ................................ ................................ ................. 14 API Method ................................ ................................ ................................ ............................ 16 Method Burland (1973) ................................ ................................ ................................ ........... 17 Method (US Army Corps of Engineers, 1992): Vijayvergiya and Focht (1972) .................... 18 2.3 End bearing capacity in cohesive soil ................................ ................................ ............................... 19 2.4 Side Shear Resistance in Cohesionless soil ................................ ................................ ....................... 20 method by Bushan (1982) ................................ ................................ ................................ ....... 20 2.4.2 Nordlund Method (1979) ................................ ................................ ................................ ............ 20 2.5 End bearing capacity in Cohesionless soil (Thurman Method) ................................ ......................... 24 2.6 Methods Based on Filed Testing of Piles ................................ ................................ .......................... 26 2.6.1 SPT (Meyerhof Method) ................................ ................................ ................................ ............ 26 2.6.2 CPT method by Nottingham and Schmertmann ................................ ................................ ......... 26

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iii 2.6.3 Static Load Testing ................................ ................................ ................................ ..................... 28 2. 6.4 PDA (Pile Driver Analyzer) ................................ ................................ ................................ ....... 30 3. Leyden clay, engineering properties of Leyden clay ................................ ................................ ............... 31 3.1 Placement and compaction of the Clay in Tiger Cage for large scale model test of Driven Pile. ..... 34 3.2 Undrained shear strengths of Leyden clay, evaluation methods, and undisturbed sampling ............ 37 3.2.1 Unconfined compression test ................................ ................................ ................................ ...... 39 3.2.2 Unconsolidated Undrained Triaxial Tests Method (UU Test) ................................ ................... 40 3.2.3 Discussion of the test results ................................ ................................ ................................ ...... 41 4. M odel test of driven H pile ................................ ................................ ................................ ..................... 44 4.1 Pile performance monitoring instrumentation program ................................ ................................ .... 44 4.2 Pneumatic pile driver, and driving load frame. ................................ ................................ ................. 46 4.3 M odel test of steel H pile installation and performance ................................ ................................ .... 46 4.4 Performance of static load test for H pile ................................ ................................ .......................... 52 4.5 Pile examination after test ................................ ................................ ................................ ................. 56 5. Nominal capacity of H Pile in Leyden Clay ................................ ................................ ........................... 67 ................................ ............................... 68 5.2 Comparison between the nominal capacity and STL result ................................ .............................. 74 5.3 Discussion of the result ................................ ................................ ................................ ..................... 74 6. Finite Element Analysis ................................ ................................ ................................ .......................... 75 6.1 Pile analysis with SSI3D Program ................................ ................................ ................................ .... 75 6.2 Results and conclusion ................................ ................................ ................................ ...................... 79 7. Bias Factor ................................ ................................ ................................ ................................ ............... 97 8. Summary, Conclusions, and future studies ................................ ................................ ............................. 98 References ................................ ................................ ................................ ................................ ................. 102

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iv F IGURES Figure 1.1 Conditions that require the use of pile foundations. Das, B. (2010) ................................ ............ 2 Figure 1.2 Different Types of Piles ................................ ................................ ................................ ............... 3 Figure 1.3 Type of steel piles H pile and pipe pile Das, B. (2010) ................................ ............................... 4 Figure 1.4 Precast concrete piles with ordinary reinforcement Das, B. (2010) ................................ ............. 5 Figure 1.5 Timber Pile (FHWA 2016) ................................ ................................ ................................ .......... 6 Figure 1.6 composite pile (timber concrete pile) ................................ ................................ .......................... 7 Figure 2.1a factors; Tomlinson method (Tomlinson, 1995) (After FHWA 1993) ................................ ... 15 Figure 2.1b Adhesion values for piles in cohesive soils (after Tomlinson, 1979) ................................ ...... 16 Figure 2.2 factors (AASHTO 2007) ................................ ................................ ................................ ......... 18 Figure 2.3: Coefficient for driven pile piles after (Vijayvergiya and Focht 1972) ................................ ...... 19 Figure 2.4: Design curve for evaluating ................................ ..... 21 Figure 2.5: Design curve for evaluating ................................ ..... 22 Figure 2.6: Design curve for evaluating ................................ ..... 22 Figure 2.7: Design curve for evaluating ................................ ..... 23 Figure 2.8: Correction factor (C F ) for (after Nordlund, 1979) ................................ .............................. 23 Figure 2.9: coefficient (FHWA 1998 ) ................................ ................................ ................................ .... 24 1998 ) ................................ ................................ ............ 25 Figure 2.11: Relationship between Maximum Unit Pile Toe Resistance q L (kPa) and Friction Angle for Cohesionless Soils (Meyerhof, 1976/1981). ................................ ................................ ............................... 25 Figure 2.12: Tip resistance computation procedure (Nottingham 1975) ................................ ..................... 27 Figure 2.13: Typical static load test arrangement FHWA 2006 ................................ ................................ .. 29 Figure 2.14: Pile Driver Analyzer (Chang et. al, 2018) ................................ ................................ .............. 30 Figure 3.1: Shows the Leyden Clay (Chang et. al, 2018) ................................ ................................ ............ 31 Figure 3.2: Leyden clay compaction test result (Chang et. al, 2018) ................................ .......................... 33 ................................ ................................ ..... 35 Figure 3.4: Tiger cage with compacted Leyden clay (Chang et. al, 2018) ................................ .................. 35 Figure 3.5: Location of the soil blocks (Chang et. al, 2018) ................................ ................................ ....... 38 Figure 3.6: Hand operated sample (Chang et. al, 2018) ................................ ................................ .............. 39 Figure: 3.7 Unconfined compression test (QU) (Chang et. al, 2018) ................................ .......................... 40

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v Figure: 3.8 Unconsolidated Undrain ed test (UU) (Chang et. al, 2018) ................................ ....................... 41 The Figure: 3.9 shows the variation of the undrained shear strength with depth from QU test, UU tests. (Chang et. al, 2018) ................................ ................................ ................................ ................................ ..... 43 Figure 4.1: Load transfer in an axially loaded pile (FHWA HRT 04 043) ................................ ................ 44 Figure 4.2: Selected strain gage for SLT (Chang et. al, 2018) ................................ ................................ .... 45 Figure 4.3: Loading frame and driving system (Chang et. al, 2018) ................................ ........................... 47 Figure 4.4: Strain Gages Location (Chang et. al, 2018) ................................ ................................ .............. 47 Figure 4.5: Pile surface preparation (Chang et. al, 2018) ................................ ................................ ............ 48 Figure 4.6: Machining at gage location (Chang et. al, 2018) ................................ ................................ ...... 48 Figure 4.7: SG installation and protection from step 1 to step 5 (Chang et. al, 2018) ................................ 49 Figure 4.8: Test pile instrumentation system (Chang et. al, 2018) ................................ .............................. 50 Figure 4.9: Calibration of test pile instrumentation (Chang et. al, 2018) ................................ .................... 51 Figure 4.10: Pile name and its location (Chang et. al, 2018) ................................ ................................ ....... 52 Fi gure 4.11: LVDT installation (Chang et. al, 2018) ................................ ................................ .................. 53 Figure 4.12: SLT setup for test pile (Chang et. al, 2018) ................................ ................................ ............ 53 Figure 4.13: SLT of all piles (Chang et. al, 2018) ................................ ................................ ....................... 55 Figure 4.14: Test pile after being extracted out of soil (Before removing the U shaped protector and strip protector, the electrical shorts are checked by e ach SG.) (Chang et. al, 2018) ................................ ........... 56 Figure 4.15: Measured Load from SG by Position 1 ................................ ................................ ................... 58 Figure 4.16: Measured Load from SG by Position 2 ................................ ................................ ................... 59 Figure 4.17: Measured Load from SG by Position 3 ................................ ................................ ................... 60 Figure 4.18: Measured Pile Capacity by Position 3 ................................ ................................ .................... 61 Figure 4.19: Measured load from SG by Position 4 ................................ ................................ .................... 62 Figure 4.20: Measured Pile capacity by Position 4 ................................ ................................ ..................... 63 Figure 4.21: Measured load from SG by Position 5 ................................ ................................ .................... 64 Figure 4.22: Measured Pile capacity by Position 5 ................................ ................................ ..................... 65 Figure 4.23: Measured load from SG by Position 6 ................................ ................................ .................... 66 Figure: 5.1. Axial Loading (side shear resistance and end bearing) of pile ................................ ................ 67 Figure 5.2: Relationship between adhesion factor and undrained shear strength (essentials of soil mechanics and foundation McCarthy) ................................ ................................ ................................ ......... 70

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vi Figure 6.1: Soil and Pile Model using SSI3D ................................ ................................ ............................. 76 Figure 6.2: Soil and Pile Geometry using SSI3D ................................ ................................ ........................ 77 Figure 6.3: Side shear Distribution along the pile (Pile#1) ................................ ................................ ......... 80 Figure 6.4: Total Side Shear and load transfer f rom pile to soil (Pile#1) ................................ .................... 80 Figure 6.5: Side shear Distribution along the pile (Pile#2 and pile#5) ................................ ....................... 81 Figure 6.6: Total Side Shear and load transfer from pile to soil (Pile#2 and pile #5) ................................ . 81 Figure 6.7: Side shear Distribution along the pile (Pile#3 and pile #4) ................................ ...................... 82 Figure 6.8: Total Side Shear and load transfer from pile to soil (Pile#3 and pile #4) ................................ . 82 Figure 6.1 0: End bearing Capacity Curve On the tip of the pile (Pile#1) ................................ ................... 84 Figure 6.11: End bearing Capacity Curve On the tip of the pile ( Pile#3 and pile #4) ................................ . 84 Figure 6.12: End bearing Capacity Curve On the tip of the pile (Pile#2 and pile #5) ................................ . 85 Figure 6.13: Load Experienced in the pile (Pile#1) ................................ ................................ ..................... 86 Figure 6.14: Load Experienced in the pile (Pile#2 and pile #5) ................................ ................................ .. 86 Figure 6.15: Load Experienced in the pile (Pile#3 and pile #4) ................................ ................................ .. 87 Figure 6.16: Load Experienced in the pile (Pile#5) from analysis and test ................................ ................. 88 Figure 6.17: Load and Settlement Curve (Pile#1) ................................ ................................ ....................... 89 Figure 6.18: Load and Settlement Curve (Pile#3 and pile #4) ................................ ................................ .... 89 Figure 6.19: Load and Settlement Curve (Pile#2 and pile #5 Instrumented pile) ................................ ....... 90 Figure 6.20: Load and Displacement Curve (Pile#1) ................................ ................................ .................. 91 Figure 6.21: Load and Displacement Curve (Pile#3 and 4) ................................ ................................ ........ 91 Figure 6.22: Load and Displacement Curve (Pile#2 and #5) ................................ ................................ ...... 92 Figure 6.23: Load and Displacement Curve (Pile#1) ................................ ................................ .................. 93 Figure 6.24: Load and Displacement Curve (Pile #2 and #5) ................................ ................................ ...... 94 Figure 6.25: Load and Displacement Curve (Pile#3 and 4) ................................ ................................ ........ 94 Figure 8.1: New design for pile instrumentation (Chang et. al, 2018) ................................ ...................... 101

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vii TABLES Table 1 : Summary of static analysis methods for piles in cohesive soils. (Reese, 2006) ........................... 13 Table 2: Proctor Compaction Result (Chang et. al, 2018) ................................ ................................ ........... 33 Table 3: Water added for each layer (Chang et. al, 2018) ................................ ................................ ........... 36 Table 4: Summary of QU and UU test results (Chang et. al, 2018) ................................ ............................ 42 Table 5: Penetration depth before SLT (Chang et. al, 2018) ................................ ................................ ....... 53 Table 6: Total bearing capacity and settlement of all piles (Chang et. al, 2018) ................................ ........ 55 Table 7: Measured force from SG and comments (Chang et. al, 2018) ................................ ...................... 57 Table 8: The undrained shear strengths of the Leyden clay (Chang et. al, 2018) ................................ ....... 68 Table 9: Properties and units used in calculation ................................ ................................ ........................ 69 Table 10: Comparison of nominal capacity and SLT (Chang et. al, 2018) ................................ ................. 74 Table 11: Properties and units used in Finite Element Analysis ................................ ................................ . 79 Table 12: side shear, end bearing and total capacity from FEA ................................ ................................ .. 85 Table 12: Nc Value for each pile ................................ ................................ ................................ ................ 96 Table 13: Comparison between SLT and nominal capacity (Chang et. al, 2018) ................................ ....... 97 Table 14: Comparision between the Capacities from calculations, test and Analysis .............................. 100

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1 1. Introduction 1.1 Foundation types The foundation is the part of a structure that transmits the weight of the structure onto the natural ground. If a stratum of soil suitable for sustaining a structure is located at a relatively shallow depth, the structure may be supported directly on it b y a spread foundation However, if the upper strata are too weak, the loads are transferred to more suitable material at greater depth by means of piles or piers. Based on that, the foundation can be divided into two categories: Shallow foundations : defined as a foundation that bears to a depth less than about two times its width. A shallow foundation can be used in such cases (1) the soil close to the ground surface has sufficient bearing capacity, and (2) underlying weaker strata do not result in an undue settlement. The shallow foundations are usually used most inexpensive foundation systems. Deep foundations : Deep foundations: deep foundations transfer loads to a stronger layer, which can be located at a significant depth below the ground surfac e. The load is transferred by skin friction and end bearing (Figure below). Piles are structural members made of steel, concrete, or timber. Deep foundations pricing is more than shallow foundations because of the way of construction. Despite the cost, the use of piles often is necessary to guarantee structural safety. a list to identifies the conditions that require pile foundations . (Das, B. (2010)) 1. Piles are used to transfer the structural load to the soil gradually. When bedrock is not found at a re asonable depth below the ground surface. if there is more than one soil layer is very compressible and too weak to carry the load transferred from the superstructure, piles are used to transfer the load to a stronger soil layer such as a bedrock layer. The resistance to the applied structural load is determined mainly from the frictional resistance developed at the soil pile Interface. (Figure 1 .1a) and ( See Figure 1 .1b). 2. Pile foundations resist by bending when still supporting the vertical load transferred by the superstructure and it's counted in the construction and design for foundations of high rise buildings that subjected to Dynamic forces such as earthquake forces or wind. ( See Figure 1 .1c)

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2 3. In many c ases, expansive and collapsible soils may be present at the site of a proposed structure. These soils may extend to a great depth below the ground surface. In Expansive soils swell and shrink when the moisture content changes and the pressure of the swelli ng can be considerable. If the shallow foundations used in these conditions, the structure may suffer serious damages. Pile foundations can be as an option when piles reached the active zone, swelling and shrinking occur in this zone. In these cases, pile foundations may be used in which the piles are reached into steady stable soil layers where moisture will change. (See Figure 1 .1d.) 4. Foundations of structures like mat basement under the water table level, offshore platform, and towers, subjected to uplift forces. The use of piles resists that force. (See Figure 1 .1e.) 5. Normally structures as piers and bridge abutments built over piles to avoi d the loss of the bearing capacity that might be experienced in shallow foundations because of the erosion of soil at the ground surface. (See Figure 1 .1f.). Figure 1.1 Conditions that require the use of pile foundations. Das, B. (2010)

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3 1.2 Pile types and H piles and Pipe piles are used in Colorado 1.2.1 Pile types In construction work, different types of piles used and it depends on the load carried, location of table water level and the soil condition. in general conditions, piles can be categorized in to (a) steel piles (b) concrete piles (c) timber piles, and (d) composite piles Figure 1.2 Different Types of Piles (a) Steel Piles Steel piles are pipe piles or H piles. Pipe piles are even open end or closed end, and in many cases, they are filled with concrete after they have been driven. I section beams can be used as piles also but H piles are preferred because of the thickness of the flange and web are equal (The I secti on beams, their web thicknesses are smaller than the flange thicknesses).

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4 Figure 1.3 Type of steel piles H pile and pipe pile Das, B. (2010) (b) Concrete Piles Concrete piles can be divided into two categories: (a) precast piles and (b) cast in place piles. Precast piles can be prepared by using regular reinforcement, and they can be shaped as square or octagonal in cross section. The use of Reinforcement is to enable th e pile to resist the bending moment that may be generated by picking up the pile and transport it to the site. And to resist the bending moment generated by a lateral load. The piles are cast to desired lengths and cured before it transported to the site.

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5 Advantages: a. It Resist hard driving . b. Resist corrosion. c. It is easy to combine with a concrete superstructure . Disadvantages: a. Hard to manage a proper cutoff. b. Hard to transport to the site. Cast in place piles is constructed of concrete filled in a hole in the ground. Several types of cast in place concrete piles are used in construction. These piles may be divided into two categories: (a) cased and (b) uncased. Both of them may have a bottom pedestal. Cased piles are constructed by push ing a case made of steel into the ground and a mandrel placed inside that casing. As the pile reaches the right depth, take off the mandrel out and then fill the casing with concrete Advantages: a. Relatively cheap b. It can inspected before pouring the concrete c. Easy to extend Disadvantages: a. Difficult to join after concreting b. may damage the casing during the driving Figure 1.4 Precast concrete piles with ordinary reinforcement Das, B. (2010)

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6 (c) Timber Piles Timber piles are made of tree trunks that their branches and bark carefully cut off. Most length of timber pil es is 10 to 20 m (30 to 65 ft). T he timber should be straight, sound, and without any defects to be qualified to be used as a pile. ( The American Practice, No. 17 (1959) ) , divided timber piles into three classes: 1. Class A piles: these kinds of timber piles can carry heavy loads. And their minimum butt diameter can be 356 mm (14 in.). 2. Class B piles: these k inds of timber piles can carry medium loads, and their minimum butt diameter can be 305mm to 330 mm (12in to 13 in.). 3. Class C piles: this class of pile used in temporary construction work. Permanently used only if the entire pile is below the water tabl e level. And their minimum butt diameter can be 305 mm (12 in). In all cases, the tip of the pile should have a diameter bigger than 150 mm (6 in.). Timber piles cannot handle hard driving; so, the pile capacity is limited. To avoid damage to the pile bo ttom tip, steel shoes may be used. And for the top of pile damage may also occur during the driving process. A metal band or a cap may be used to avoid the damage. If they are expected to carry a tensile load or a lateral load, Timber piles should not be s pliced. If timber piles surrounded by saturated soil, it may stay undamaged. Preservatives can be used to increase timber piles life such as creosote. Figure 1.5 Timber Pile (FHWA 2016)

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7 Composite Piles They are made of different types of materials, for example, it may be constructed of steel and concrete or timber and concrete. For the Steel and concrete piles, the lower part is made of steel and an upper part of cast in place concrete. This kind of pile is can be used when the pile length required for a dequate bearing exceeds the capacity of entirely cast in place concrete piles. Timber and concrete piles usually consist of an upper portion of concrete and a lower portion of timber pile is below the water table. In many cases, forming decent joints betwe en two different materials are difficult, and for the reason above, composite piles are not commonly used. Figure 1.6 composite pile (timber concrete pile) 1.2.2 H pile and pipe piles Colorado uses Within the widely varying physiographic terrains in Colorado, principal geologic factors that affect the design, construction, and performance of pile foundations are (1) the thickness and character of unconsolidated sediments, (2) the underlying bedrock quality and composition, and (3) the geom Plains, soil and bedrock conditions are suitable for end bearing steel H piles where bedrock is shallow or friction pipe piles where bedrock is deep. Setup, relaxation, and d ensification effects can potentially occur during/after the driving of steel H and pipe piles and need to be taken into consideration in the design process.

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8 End Bearing Piles Where the bedrock is shallow, CDOT usually drives a steel H pile into bedrock as an end bearing pile, where the structure capacity controls the pile design. With the grade of steel used in the steel H piles moved up from Grade 36 to Grade 50, the design capacity of H piles is expected to increase. CDOT has adopted the blow count base d pile capacity evaluation method, where the allowable pile capacity is set to be N/2 ksi or 9 ksi, whichever is smaller. The effectiveness of this method needs further assessment. Friction Piles Where the bedrock is deep, CDOT uses steel pipe piles as f riction piles. Pipe piles are normally plugged to enhance soil densification along the length of piles enabling them to achieve required geotechnical capacities at a reduced penetration depth. The required geotechnical capacity is normally estimated by app lying a safety factor of no less than 2 to the allowable structural capacity. To choose a proper pile type and size. PDA with CAPWAP is recommended to determine the geotechnical capacity versus depth relationship, particularly when the effort to evaluate t he Colorado specific resistance factors is underway. 1.2.3 Driven H piles advantages and disadvantages D riven H pile Steel H piles are high capacity, low displacement piles (since the cross sectional area is not very large ) hard stratum. The name H pile refers to the shape of the pile cross section. They consist of two flanges and a web of varying widths, depths, and thicknesses. The H piles are formed using a metal forming process called rolling. The benefits of driven steel H piles are attractive to both contractors and designers due to their low costs, simple design, easy installation, and high bearing capacity. H piles are versatile, easy to handle, and have good driving characteristics . Advantages . High load carrying c apacity . Can be installed with conventional driving equipment . Can withstand high driving stresses . Penetration proficient . Have good resistance to buckling . Reduced ground vibrations. Low displacement of the bearing soil a minimal heave of adjacent piles or structures . Easy to handle with respect to cutoff an extension to the desired length

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9 . Durable . Low supply and construction costs for heavy structural loads. . Can penetrate in har d layers like soft rock and dense gravel Disadvantages . High cost . Noise during pile driving . Corrosion effect. . May be damaged or deflected during driving in hard layers 1.3 Load and Resistance factor designs 1.3.1 History and reasons for Load and Resistance Factor Design (LRFD) Over the past 18 years there has been a general move toward the increased use of LRFD in structural and geotechnical design practice. In order to achieve a consistent design for both the superstructures and the foundations, the AASHTO LRFD Specifications. The LRFD approach requires that the load and resistance factors be defined. For the geotechnical design of driven piles, AASHTO guidelines provide the resistance fact ors for general soil conditions and for several static pile capacity analysis methods. There is always a concern about the survival of the bridge and protection of life safety (some damage to the structure is allowable). The basic equation for load and res istance factor design (LRFD) states that the loads multiplied by factors to account for uncertainty, ductility, importance, and redundancy must be less than or equal to the available resistance multiplied by factors to account for variability and uncertain ty in the resistance. The basic equation, therefore, is as follows: (1.1) Where: i : is the force effect on the foundation (e.g., axial compression load) from a load applied on the bridge (e.g., dead load) and i : is the load factor for that load (e.g., dead load). i : geotechnical resistance available to resist the force effect (e.g., shaft side or resistances) and

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10 i is its resistance factor i i will account for the uncertainties in the computation of each load component and resistance component. i : is a load modifier relating to ductility, redundancy, and operational importance. 1.3.2 Advantages and Disadvantages of using (LRFD) The advantages o f the LRFD: theory of probability. safety can be assured. updating of the load and resistance fact ors. will be consistent with the design of other components of a civil engineering system. out much complication. Calibration of LRFD is usually done for an average situation, but it might need to be adjusted in the future. however, at least the LRFD provides the approach. The disadvantages of the LRFD are: and a change in design procedures.

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11 1.4 Model test of driven H pile tests Large scale model tests of 4 inch steel model H n house pneumatic pile driver. All the model test apparatuses were designed and fabricated in house at the CGES laboratory at the UC Denver. In the model test, Leyden clay from Golden, Colorado was compacted in the Tiger Cage to the maximum dry density fro m the modified Proctor Compaction. The bottom 1.5 feet of clay was compacted to provide the strength of clay shale, an Intermediate Geomaterials (IGM). A comprehensive laboratory test program provides all material parameters for pile performance assessment . Five 4 inch steel H piles were driven with the in house pneumatic pile driver. Piles are equally spaced with the center pile heavily instrumented with strain gages to measure end bearing capacity and side shear distribution and to test the survivability of strain gages during driving for a feasibility study for field installation. Each pile was driven into the hard clay with tip elevation about 16 inches above the base of Tiger Cage . 1.5 Study Objective The objective of this thesis is to study the behavior of the pile driven in a hard stiff clay, find out the total capacity from Static Load Test, method and Finite Element Method and c ompare between the pile capacities from all three cases, analyze the pile using Finite Element Analysis p rogram using SSI3D software, and calculate the Bias Factor .

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12 2. Literature review on nominal capacity calculation for H piles in sand and clay 2.1 Pile capacity theories The geotechnical capacity of an axially loaded pile is defined as the ultimate soil resistance at the point where the pile either plunges down into the ground without any further increase in load or the displacement at the pile head is too great for the su perstructures. The use of static equations to compute the geotechnical capacity of piles is well established, and numerous procedures have been suggested. The bearing resistance of a pile is the sum of the tip resistance and skin friction (or shaft resistance). However, the shaft resistance of piles driven in cohesive soils is frequently as much as 80 90% of the total capacity. The pile load design should be supported by soil resistance developed only in soil layers that provide long term load suppor t . (Reese , 2006) = (2.1) Where: Q s : total skin friction resistance, lb (kN), Q p : total end bearing, lb (kN), Qs: unit load transfer in skin friction (normally varies with depth), lb/ ft 2 (kPa), q p : unit load transfers in end bearing (normally varies with depth), lb/ ft 2 (kPa), A p : gross end area of the pile, ft2 (m2), and A s : side surface area of the pile, ft 2 (m 2 )

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13 Table 1 : Summary of static analysis methods for piles in cohesive soils. (Reese , 200 6) Side resistance and End bearing in cohesive soil Method Pile side resistance Pile tip resistance Parameters Tomlinson Method Su =undrained shear strength of the soil Method Burland (1973) =vertical effective stress Method = Is the coefficient that is based on the embedment length of the pile = mean effective vertical stress = undrained shear strength of soil Side resistance and End bearing in cohesionless soil Method Pile side resistance Pile tip resistance Parameters method by Bushan = an empirical coefficient can be found using = vertical effective stress Dr = Is the Relative Density Where: = dimensionless coefficient = Bearing capacity factor = Effective overburden pressure at the pile tip = Limiting unit tip resistance

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14 Nordlund Method = Coefficient of lateral earth pressure at midpoint of soil layer = correction factor for = angle of pile taper from vertical = friction angle between pile and soil Where: = dimensionless coefficient = Bearing capacity factor = Effective overburden pressure at the pile tip = Limiting unit tip resistance 2.2 S ide resistance in cohesive soil Tomlinson Method The Tomlinson Method (by Tomlinson 1979), is widely used in stiff clay. And can be used in different types of piles such as (steel, concrete and timber). Its gives fair capacity value for piles that have large displacement. Th e unit skin resistance is as follows: (2.2) Where: =Adhesion factor from S u =undrained shear strength of the soil

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15 Figure 2.1 a factors; Tomlinson method (Tomlinson, 1995) (After FHWA 1993)

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16 Figure 2.1 b Adhesion values for piles in cohesive soils (after Tomlinson, 1979) 2.2.2 API Method Method ( API 1974), is another way to compute the skin friction for piles. Using total stress approach using the undrained shear strength (S u ), in cohesive soil. It provides reasonable capacity for both displacement piles and non displacement piles. The unit skin resistance is as follows: (2.3)

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17 od is easier by using: = the vertical effective overburden pressure Method Burland (1973) This method can be used for different types of soil (Clay, Gravel or Silt) and even in layered soil profile. This method developed to model drained shear strength for long term: ( Burland 1973 ) factor can be effected by: Soil type. Mineralogy Density Strength Pile insulation technique is a value between 0.23 0.8 and cannot exceed 2 for Over consolidated soil. The unit skin resistance is as follows: (2.4) Where: K =horizontal stress ratio =adhesion angle between pile and soil =vertical effective stress and can be found depend on Over consolidation ratio (O.C.R) So, (2.5)

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18 Figure 2.2 factors (AASHTO 2007 ) Method (US Army Corps of Engineers, 1992) : Vijayvergiya and Focht (1972) They proposed a method to estimate the skin friction capacity of piles imbedded in Over method; it has been proposed for estimating the skin resistance of long steel pipe piles installe d in clay. The unit skin resistance: (2.6) Where: = Is the coefficient that is based on the embedment length of the pile and can be obtained by (Figure 2. 3 ) = mean effective vertical stress = undrained shear strength of soil

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19 Figure 2.3: Coefficient for driven pile piles after ( Vijayvergiya and Focht 1972) 2.3 End bearing capacity in cohesive soil For cohesive soil the end bearing capacity can be obtained using ( ) capacity equation c to find the end bearing using the undrained shear strength as follows : (2.7) Where: = Is unit end bearing resistance . = The bearing capacity coef ficient that can be assumed equal to 9.0

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20 C = Undrained shear strength at the tip of the pile, usually taken as the average over a distance of two diameters below the tip of the pile . 2.4 Side Shear Resistance in Cohesionless soil In cohesionless the volume displacement, material, shape of the pile. met hod by Bushan (1982) By Bushan (1982) (2.8) Where: = an empirical coefficient = vertical effective stress can be found using (2.9) Dr = Is the Relative Density 2.4.2 Nordlund Method (1979) Nordlund (1979) has developed a calculating method for the skin friction based on field observation reports and results of several pile load tests in cohesionless soils. Several pile types were used including (Timber, H piles, Pipe piles, and others) (2.10) = Coefficient of lateral earth pressure at midpoint of soil layer = correction factor for = angle of pile taper from vertical = friction angle between pile and soil When ,

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21 (2.11) Figure 2.4: Design curve for evaluating (after Nordlund, 1979)

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22 Figure 2.5: Design curve for evaluating = 30 (after Nordlund, 1979) Figure 2.6: Design curve for evaluating = 35 (after Nordlund, 1979)

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23 Figure 2.7: Design curve for evaluating = 40 (after Nordlund, 1979) Figure 2.8: Correction factor (C F ) for (after Nordlund, 1979)

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24 2.5 End bearing capacity in Cohesionless soil (Thurman Method) (2.12) Where: = dimensionless coefficient = Bearing capacity factor = Effective overburden pressure at the pile tip = Limiting unit tip resistance Figure 2. 9: coefficient (FHWA 1998 )

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25 Figure 2.10: bearing (FHWA 1998 ) Figure 2.11: Relationship between Maximum Unit Pile Toe Resistance q L (kPa) and Friction Angle for Cohesionless Soils (Meyerhof, 1976/1981).

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26 2.6 Methods Based on Filed Testing of Piles 2.6.1 SPT (Meyerhof Method) Based on Meyerhof Method 1976 (2.13) = Representative SPT blow count near pile tip Advantages: of the wide use of SPT test and the availability of data. Disadvantages: Non reproducibility of N values. It s not reliable as other methods in finding capacity of piles 2.6.2 CPT method by Nottingham and Schmertmann ( Nottingham and Schmertmann 1975) to calculate the pile capacity which can be used for cohesion and cohesionless soil and based on CPT test. and it takes into consideration the multilayer soil profile. The ultimate tip resistance: (2.14) = average static cone tip resistance over a distance of yD below the pile tip = average static cone tip Resistance over a distance of 8D above the pile tip

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27 Figure 2.12: Tip resistance computation procedure ( Nottingham 1975 ) And the Nominal side resistance computed from equation below (2.16) Where: = correction factor for clay and sand = depth to middle of length interval i = pile width or diameter and a considered point = sleeve friction resistance from cone penetration test = pile perimeter = length interval

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28 = intervals between ground surface and 8D below surf ace = number of intervals between 8D below the ground surface and the tip of the pile The disadvantage of this method is the limitation on pushing cone into dense strata. 2.6.3 Static Load Testing method because in static load testing the load apply very slowly . It used to get th e true actual capacity of the pile under axial load. This kind of test gives the Displacement load Relationship at the head of the standard for testing and mate rials) discuss the procedure of static load testing. And there are four types of static load testing: standard loading procedure, cyclic loading, quick load test and constant rate of penetration.

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29 Figure 2.13: Typical static load test arrangement FHWA 2006

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30 2.6.4 PDA (Pile Driver Analyzer) pile from blows of the hammers during and/or redrive of the instrumented pile. It considered as a field instrument to measure the force acceleration during the pile driving by a pair of strain transducer and accelerometer located on the top of the pile head and PDA to collect t he data from them. And the procedure standardized in ASTM D4945. Figure 2.14: Pile Driver Analyzer (Chang et. al, 2018)

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31 3. Leyden clay, engineering properties of Leyden clay abundant in the areas around City of Golden and parts of foothill range. Figure 3.1 : Shows the Leyden Clay (Chang et. al, 2018) Introduction to Proctor Compaction Test The Proctor compaction test is a laboratory process used to determine the optimal moisture content for a given type of soil will be so dense and it achieves the maximum dry density. And its named after Ralph Proctor, in 1933 explained that the dry density for a given compacted soil depends on the amount of water that the soil contains during the compaction. The original test is generally called as the standard Proctor compaction test; the test was updated to the modified Proctor compaction test. For the Standard procedure, it used to determine the relationship between water content and dry unit weight of soils compacted in a 4in or 6in diameter mold and a 5.5 lb Dropped hammer of a height of 12 in producing a compactive effort of 12,400 ft lb/ft3. A soil at a known water content is put in three layers into a mold of known dimensions, for each layer, the hammer compacted the soil into 25 blows. Then the dry unit weight is then defined. The

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32 procedure repeated for enough number of water contents to get a relationship between the water content of the soil and the dry unit weight. Modified Proctor procedure it is a procedure used to define the relationship between water content and dry unit wei ght of soils compacted in a 4in or 6in diameter mold with a 10 lb. dropped hammer to a height of 18 in producing a compactive effort of 56,000 ft lb/ft3. Five layers of soil at a chosen water content are placed into the mold of a given dimension, each laye r compacted by 25 blows by using the hammer. The dry unit weight then determined. Repeat the procedure for a sufficient amount of different water content to get a relationship between the water content of the soil and the dry unit weight. For these tests ( ASTM) The American Society for Testing and Materials standards and (AASHTO) The American Association of State Highway and Transportation Officials standards are followed to choose the equipment and for the procedure. ASTM D698 and AASHTO T99. And the modif ied Proctor compaction test is characterized by ASTM D1557 and AASHTO T180 D. For our test, the clay was weighed and compacted in 2 inch layers in the Tiger Cage at no less than 95% of its maximum dry density obtained in the modified Proctor compaction and an appropriate moisture content on wet side. The bottom 18 inches were compacted to reach an undrained shear strength of hard clay with undrained shear strength of around 2800lb/ft 2 to simulate the shear strength of clay shale. And the table (2 ) below con tain the result of both Standard Proctor rest and Modified Proctor test. And (F igure : 3.2) shows the Optimum moister content and Maximum Dry Density .

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33 Figure 3.2: Leyden clay compaction test result (Chang et. al, 2018) Table 2 : Proctor Compaction Result (Chang et. al, 2018) 80 85 90 95 100 105 110 115 120 125 10 12 14 16 18 20 22 w [%] Compaction test of Leyden Clay Standard Proctor Test Modified Proctor Test Optimum Moisture Content (%) Max imum Dry Density (pcf) Standard Proctor Compaction 16 110 Modified Proctor Compaction 11.7 120

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34 3.1 Placement and compaction of the Clay in Tiger Cage for model test of Driven Pile. F or the placement and compaction of soil in the Tiger cage, we followed the modified Proctor compaction test result. The water content calculated was around 11.7 %, and the dry density was close to 120 pcf. The water con tent of the before adding the 11.7 % water was 3.66%. Divided the total depth of the tiger cage into 31 layers in order to make the water content in the soil uniform. The soil and water weight in each layer was calculated by the moisture content, the original water content in the soil, and the expected dry density. The weight of soil and water adde d to each layer shown in (Table 3 ) . For crushing and compacting the soil, jumping jack was used for this purpose. And we used Pig car to move soil and dip it inside the tiger cage. Pig car t and J u mping Jack shown in F igure (3.3 ) and Tiger Cage shown in Figure (3.4 ) For each layer, the procedure below was followed 1) Mark the wall of the tiger cage 2) Break the big soil particle by using the jumping jack 3) Put a tarp inside the pig car t to make it easier when dumping the soil in the tiger cage. 4) Put half of the soil and half of the water weight inside the pig car for current layer. And weigh it by four large scales, then mix the soil and add another half weight of the soil and water again to the s ame layer and mix the water added to the soil inside the pig car until it uniform. t 6) Dump the soil into the tiger cage by using the crane to carry the Pig car. 7 ) Compact the soil inside the tiger cage by using the Jumping Jack, and making sure that the surface is level to the mark on the Tiger Cage. Repeat the procedure for each layer of soil. The total depth of the soil is 64 in, and after compacting the whole soil inside the Tiger Cage total density became 145 Ib/ft 3 .

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35 t (Chang et. al, 2018) Figure 3.4: Tiger cage with compacted Leyden clay (Chang et. al, 2018)

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36 Table 3 : Water added for each layer (Chang et. al, 2018) Number of layers Thickness of each layer (in) weight of the Soil Water added to each layer (lbs) (lbs) 1 2 400 27.5 2 2 390 27.5 3 2 380 27.5 4 2 390 27.6 5 2 390 27.6 6 2 390 27.6 7 2 390 32 8 2 400 32 9 2 380 32 10 2.25 490 40 11 1.75 290 24 12 2.25 470 42 13 2.25 480 40 14 2 400 32 15 2 450 32 16 2.25 480 32 17 2 440 32 18 2 420 32 19 2 430 32 20 2 430 32 21 2.25 450 32 22 2 440 32 23 2.25 450 33 24 2 430 32 25 2 440 32 26 2 430 32 27 2.25 470 32 28 2.25 460 32 29 2 430 32 30 2 430 32 31 2.25 470 32

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37 3.2 Undrained shear strengths of Leyden clay, evaluation methods, and undisturbed sampling Sampling procedure After the test is done, the next step is to derive the undrained shear strength of the soil. The undisturbed soil sample need to be taken to run the shear test. Taking undisturbed soil sample is a big challenge . The locations to take the samples must be considered very care fully. The soil avoided. During the sampling procedure, two sampling methods were used. The sample at the depth of 10 in below the surface were taken by hammer. Th e sample tubes were hammered into the clay deposit. The sampling procedure for other deeper samples is shown below: 1) Take the block samples a. Plan where to take the samples from. b. Mark the depth on the Tiger Cage wall to take samples. c. Dig the needless soil out to reach required depth for the sample. Used the shovel to get the undisturbed block samples. The dimension of the blocks need to be bigger than 4inX4inX4in cube. Marked the location of the simple, then used the plastic drop cloth to cover it to keep the moisture. The block sample location is shown in (Figure: 3.5). The soil samples are extruded from the sampling tubes, which are pushed into the soil block taken from the Tiger Cage during excavation process. Some soil blocks are quite thin and are unable to sample more than one specimen (A and B block), the left ones are big enough to take two specimens (C, D and E block), one for QU test and another one for UU test.

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38 Figure 3.5: Location of the soil blocks (Chang et. al, 2018) 2) Take the tube sample a. Put the block sample on the MTS test table. b. Put grease on both inside and outside surface of the sample tube. c. Put the sample tube on the top surface of the sample block. d. Used the MTS loading frame to push down th e sample tube into the soil. e. Put one more tube on the top of the tube which was used to make the top of the tube under the block surface. Then we can get a full sample. Two samples were taken by on sample block. f. Used spatula to cut and fill in some soil on each side of the sample to make it level for tests. g. Put the plastic wrap around the soil sample, and bonded it with black tape. h. Used the ha nd operated sample ejector (Figure: 3.6) to take the sample out of the tube

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39 Figure 3.6: Hand operated sample (Chan g et. al, 2018) Finally, as some sample were damaged during sampling, just 10 samples were ready for the tests. 3.2.1 Unconfined compression test The 20 kip MTS machine was used as a compr ession loading machine in both Unconfined C ompressio n and Unconsolidated U ndrained Triaxial tests. The vertical displacement of all specimens was limited to less than 0.8 inches, i.e. 20% of sample the height (4 inches). The loading time was set to 20 minutes. The ( Fig ure: 3.7 ) shows a QU test in progress

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40 Figure: 3.7 Unconfined compression test (QU) (Chang et. al, 2018) 3. 2.2 Unconsolidated Undrained Triaxial Tests Method (UU Test) A UU test can yield the undrained shear strength of clay in less than 30 minutes. When the confining pressure in UU tests is set to zero, it becomes an unconfined compression test (or q u test). When two specimens were obtained from the same block sample, one is used for q u test and other for UU test. The resulting undrained shear strengths were compared and it was found that the q u tests provides a much smaller undrained shear strength then UU tests or back calculation. Thus, q u results were abandoned from any further use in this research. The ( Fig ure: 3.8 ) shows a UU test in progress

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41 Figure: 3.8 Unconsolidated Undrai ned test (UU) (Chang et. al, 2018) 3.2.3 Discussion of the test results R esult summary The average water content for the soil compacted in the Tiger Cage is 15.54%. The undrained shear strength was calculated by: The Stress VS. Strain Curves for the QU and UU soil test . The undrained shear strength estimated from unconfined compression test s and U nconsolidated U ndrained T riaxial tests are summa rized in Table 4 .

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42 Table 4 : Summary of QU and UU test results (Chang et. al, 2018) Depth inches QU Test UU Test Sample c u [psf] Sample c u [psf] 10 A1 1263.6 35 B2 1202.4 B1 2472.9 B3 2346.9 39 C1 1 2612.0 C1 2 2937.4 43 D1 1 2978.9 D1 2 3134.5 46 E1 1 798.4 E1 2 2669.9

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43 The Figure: 3.9 shows the variation of the undrained shear strength wi th depth from QU test, UU tests. (Chang et. al, 2018) Discussion The distribution of undrained shear strength with depth from both QU and UU te sts were summarized in ( Figure : 3.9 ) The figure shows that the undrained shear strength from QU tests was much smaller than the undrained shear strength from UU tests. In any future compaction placement of clay in Tiger Cage, placement moisture should be c losely controlled and the compaction operation should be completed as expeditiously as possible and sampling procedures should be improved and more samples should be secured for more reliable evaluation of the undrained shear strength of soil. 0 10 20 30 40 50 60 500 1500 2500 3500 Depth to the soil surface (in) Undrained Shear Strength (psf) Undrained Shear Strength with Depth QU test results UU test results

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44 4. Model te st of driven H pile 4.1 Pile performance monitoring instrumentation program method or can be estimated by PDA system. This nominal capacity is then verified with the real pile capacity from static load test Figure 4.1 : Load transfer in an axially loaded pile (FHWA HRT 04 043) The total pile capacity is the sum of side shear capacity and end bearing capacity and is distributed along its depth as shown in ( Figure : 4.1) To differentiate the two components, we installed strain gauges at different depth of the pile, at the top of the pile and on both sides of the web of the steel H pile to double check measurement accuracy. The top strain gauge should be locate d at no closer than 2*width of the pile to avoid the influence of Saint Venant Effect. Which is: the difference between the effects of two different but statically equivalent loads become very small at sufficiently large distance from load. The strain meas ured in stain gauge can be converted to the stress and then the equivalent longitudinal force at the corresponding gauge location using calibration factor.

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45 Then, the calibration procedure for the test pile as well as the test setup and results will also be discussed in detailed. After tested pile extraction, they were examined to reveal instrument deficiency in current design and suggestions for future improvement. The success of the strain gauge reading rate was about 67%. So for future studies new insta llation mechanism should be invented to get a better strain gauge reading. Strain Gauges (SG) and accessories Strain Gages: SGT 4/1000 FB11 is a full bridge SG (refer to Figure 4.2), which offers the best way to measure the small axial strain of beam. All four gages inside the full bridge are already aligned with respect to each other guaranteeing exact measurement. Moreover, internally gages share common ribbon leads, which save wiring time. In the limited area in small H 4/13 pile, the gages can be easily installed and protected against the soil surrounding the pile. The nominal high signal voltage to facilitate signal measurement with less noise effect. Micro Measurement (MM) Bondable Terminal Patterns Type C Solder Pads, MM M bond 200 adhesive kit, MM CSM 2 Degreaser, MM M Prep Conditioner, and All cable TEF2202STJ signal wires were used in the installation. Surgical shears, tweezers, and MM PCT 2M Installati on tape were used in the installation as well. Figure 4.2: Selected strain gage for SLT (Chang et. al, 2018)

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46 Data Acquisition System Tekpower TP1342U power supply offers four stable independent 0 to 30V/to 2A output, which matches perfectly with the se lected strain gages, which work effectively under 20 V excitation voltage. Agilent 34970A data logger offers 60 independent build in channels and can scan up to 250 channels per second. The recorded data are saved automatically in the computer system and c an be accessed easily after the test. 4.2 Pneumatic pile driver, and driving load frame. Test load frame and driving system The load frame and pneumatic pile driver were all designed, fabricated and calibrated in house (refer to Fig. 4.3). It has two big columns with the extensive base with a horizontal frame for structural stability. It also serves as the reaction frame for th e hydraulic ramp. The base of the loading frame is fixed to the top of the Tiger Cage during SLT tests to guarantee enough reaction force. The driving system is the Lynx LH3000 hydraulic ramp with 5 inch diameter bore and an oil compressor, which can produ ce a 3000psi pressure. In total, the driving system can produce more than 58 kips load. 4.3 M odel test of steel H pile installation and performance Test Pile Preparation One of the project goals is to capture the side friction distribution along a test pile. Strain gauges (SG) were glued on both sides of the pile web in symmetric positions to provide more precise measurement. A test pile is, however, driven into the compacted Leyden Clay first and SLT tests were performed. The SGs need to survive the dri ving abuse. Without protection, the SGs with wiring system will be easily destroyed. The protection of SG and wiring system is critical for the success of tests. The protection, however, should not affect the properties of pile testing. The signal wire is hidden in pile flange and covered with strip protector.

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47 Figure 4.3: Loading frame and driving system (Chang et. al, 2018) Strain Gage location In the first step, the gage location need to be defined. The goal of the test is to measure the total pile capacity, the end bearing capacity and also the distribution of the side friction along the pile. Hence the gage locations are chosen as follow: Figure 4.4: Strain Gages Location (Chang et. al, 2018) Tip of the pile Top of the pile

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48 The two gage a t the top and bottom of the pile are to measure the total pile capacity and end bearing capacity and the other four gages are to measure the side friction distribution along the pile. Initially, the W4/13 H pile surface is somewhat rusty and need to remove the rust by cleaning it with sand papers and alcohol before stain gauges can be glued on the surface. It was decided to machine the pile at selected locations for gage installation. Another reason to machine the pile is to make enough space to hide the si gnal wire into the flange of the pile. Figure 4.5: Pile surface preparation (Chang et. al, 2018) Figure 4.6: Machining at gage location (Chang et. al, 2018) After machining the gage locations, it needs to be cleaned with sand papers and alcohol again. Gauze pads are used to remove steel dust during this process. To keep the surface of gages clean, technicians always need to wear gloves during gage installation process.

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49 Figure 4.7 : SG installation and protection from step 1 to step 5 (Chang et. al, 2018)

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50 Figure 4.8 : Test pile instrumentation system (Chang et. al, 2018) The data logger system includes the Data logger and its power supply. As mentioned before, the Two independent power gate supply the excitation voltage for strai n gages on two side of pile web, therefore all strain gages on either side of pile web will have the same exciter voltage. The data logger monitor and record both the signal voltage V s and also the exciter voltage V e during SLT. Each side of pile web has six gates on the data logger for monitoring the signal from six SG and one gate is to monitor the excitation voltage. From the recorded signal voltage V s and the excitation voltage, V e , the relative voltage ratio V r c an be computed (4.1)

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51 Then, for the full bridge configuration and axial strain measurement, the equivalent strain can be deduced (4.2) where GF : Gage Factor of the gages (equal 2.13 for SGT 4/1000 FB11 ), (equal 0.3 for steel). After the instrumentation setup, the test pile will need to be calibrated before the SLT. Different static loads are applied on the pile head, the p ile strains are detected and recorded by strain gage and data logger system. Figure 4.9 : Calibration of test pile instrumentation (Chang et. al, 2018) The strains corresponding to each applied static load can be deduced using above equation .

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52 4 .4 Performance of static load test for H pile Sing le pile static load tests (SLT) Steel H 4/13 pile driving Five piles are driven into the soil and all of them are subjected to SLT. The driving sequence as well as pile names are described in the following drawing The Test Pile is the middle pile (pile #5) and prediction piles are piles (#1,2,3,4) Figure 4.10 : Pile name and its location (Chang et. al, 2018) Locked during constructional testing

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53 The penetration depth of each piles are different because of the space constrain and driving process , there was an alignment problem because of the space. Table 5 : Penetration depth before SLT (Chang et. al, 2018) Pile # Penetration depth before SLT [in. ] 1 49 2 46.5 3 48 4 48 5 46 Test setup for SLT using loading frame In the first step, the hydraulic ramp is placed on the horizontal structure of the loading frame. Thereafter, the loading frame with the hydraulic ramp need to be placed on the Tiger Cage, right above the pile head. The cylinder head of the ramp needs to b e adjusted to fit with the pile head. Figure 4.11 : LVDT installation (Chang et. al, 2018) Figure 4.12 : SLT setup for test pile (Chang et. al, 2018)

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54 The hydraulic ramp location on the horizontal structure then must be fixed to avoid its mobility during the SLT. The applied load is monitored by the transducer of the hydraulic ramp. Now to monitor the pile settlement during the test, the LVDT need to be installed at pile head as in (Figure: 4.11 ). The signal wires and exciter wires of the test pile are connected to the data logger to monitor the strain along test pile during SLT ( Figure : 4.12 ). The test setup is compl eted at that moment. In the Static Load Test, the ASTM D1143 07 standards and Procedure B Maintained Test are followed as loading procedure .

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55 Summary of test result Total bearing capacity of driven piles Table 6 : Total bearing capacity and se ttlement of all piles (Chang et. al, 2018) Pile # Capacity kips Total Settlement at Failure In. 1 10.69 0.08 2 8.08 0.10 3 9.23 0.12 4 10.77 0.05 5 8.95 0.08 Figure 4.13 : SLT of all piles (Chang et. al, 2018) Above figure present the SLT of all five pile. The capacity of all piles and the total pile settl eme nt are summarized in Table 6 Full capacity of the pile is mobilized by quite small settlement -2 0 2 4 6 8 10 12 0 0.1 0.2 0.3 0.4 0.5 0.6 Axial Load [kips] Settlement [in.] Single pile SLT Pile 1 Pile 2 Pile 3 Pile 4 Pile 5

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56 4.5 Pile examination after test After the SLT using the loading frame, two more SLT are perf ormed. After these tests, the test pile pulled out of the soil for examination Figure 4.14 : Test pile after being extracted out of soil (Before removing the U shaped protector and strip protector, the electrical shorts are checked by each SG.) (Chang et. al, 2018)

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57 Table 7 : Measured force from SG and comments (Chang et. al, 2018) And the values in table 7 are selected based on Data from the Strain Gauges Position Measured force from A side SG kips Measured force from B side SG kips Ave. Capacity kips Comment about the values 1 43071.6 425.861 21655.9 unrealistic data values 2 19.64 32.589 25.697 unrealistic data values 3 7.799 749.522 7.01 SG side A give expected values 4 8.205 8.499 8.351 SG of both side give expected values 5 8.958 8.769 8.863 SG of both side give expected values 6 22.869 20.706 21.787 unrealistic data values

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58 Measured capacity from SG Position 1 (42 inch below soil surface) Figure 4.15 : Measured Load from SG by Position 1 T he measured data is unrealistic -10000 0 10000 20000 30000 40000 50000 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG A1 -35000 -30000 -25000 -20000 -15000 -10000 -5000 0 5000 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG B1

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59 Position 2 (30 inch below soil surface) Figure 4.16 : Measured Load from SG by Position 2 T he measured data is unrealistic -5 0 5 10 15 20 25 30 35 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG B2 -5 0 5 10 15 20 25 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG A2

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60 Position 3 (18 inch below soil surface) Figure 4.17 : Measured Load from SG by Position 3 The graph form of strain gage A3 is expected and the data values can be used to predict the capacity of the pile. 0 1 2 3 4 5 6 7 8 9 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG A3 -8000 -7000 -6000 -5000 -4000 -3000 -2000 -1000 0 1000 2000 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG B3

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61 Figure 4.18 : Measured Pile Capacity by Position 3 0 1 2 3 4 5 6 7 8 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s]

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62 Position 4 (6 inch below soil surface) Figure 4.19 : Measured load fro m SG by Position 4 The graph form of strain gage A4 and B4 are expected and the data values can be used to predict the capacity of the pile by this location. -1 0 1 2 3 4 5 6 7 8 9 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG A4 -1 0 1 2 3 4 5 6 7 8 9 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG B4

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63 Figure 4.20 : Measured Pile capacity by Position 4 -1 0 1 2 3 4 5 6 7 8 9 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] Capacity by Position 4 (ave. values from both SG)

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64 Position 5 (6 inch above soi l surface) Figure 4.21 : Measured load from SG by Position 5 The graph form of strain gage A5 and B5 are expected and the data values can be used to predict the capacity of the pile by this location. -1 0 1 2 3 4 5 6 7 8 9 10 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG A5 -1 0 1 2 3 4 5 6 7 8 9 10 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG B5

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65 Figure 4.22 : Measured Pile capacity by Position 5 -1 0 1 2 3 4 5 6 7 8 9 10 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s]

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66 Position 6 (4 inch from pile top) Figure 4.23 : Measured load from SG by Position 6 The graph form of strain gage A6 and B6 are expected but their values are much bigger than the real applied load. So, this data cannot be used in the comparison -5 0 5 10 15 20 25 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG A6 -5 0 5 10 15 20 25 0 2000 4000 6000 8000 10000 12000 14000 F [kips] time [s] SG B6

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67 5. Nominal capacity of H Pile in Leyden Clay The total pile capacity is the sum of side shear capacity and end bearing capacity and is distributed along its depth Q ult (5.1) Figure: 5.1. Axial Loading (side shear resistance and end bearing) of pile

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68 QU and CU tests are conducted with the clay taken from Tiger Cage to determine the undrained shear strength of the compacted clay. The undrained shear strengths of the Leyden clay are showed in the following table Table 8 : The undrained shear strengths of the Leyden clay (Chang et. al, 2018) Depth i n. QU Test UU Test Sample c u [psf] Sample c u [psf] 10 A1 1263.6 35 B2 1202.4 B1 2472.9 B3 2346.9 39 C1 1 2612.0 C1 2 2937.4 43 D1 1 2978.9 D1 2 3134.5 46 E1 1 798.4 E1 2 2669.9

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69 Table 9 : Properties and units used in calculation Length ft Area ft ² Force kips W4*13 Pile Properties Area=3.83 in² = 0.0266 ft² Depth=4.16 in W idth (bf)=4.06 in T hickness (tw)=0.280 in Length of pile = 6 ft = 72 inch young's Modulus= 200000000 psf Soil Properties N c = 9 top = 0.9 bottom =0.4 Young s Modulus = 2500 psf Tiger cage Dimensions Height = 6 ft = 72 inch W idth = 2 ft = 24 inch Length = 12 ft = 144 inch Depth of soil in the Tiger cage = 5.3 ft =64 inch

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70 From soil surface to the 3ft deep layer, the c u is 1263.6 psf From 3ft deep layer to the bottom, the c u is calculated as the average values of sample B to sample E, about 2803.7 psf Using the method, the value then unit adhesion can be computed Figure 5.2 : Relationship between adhesion factor and undrained shear strength ( essentials of soil mechanics and foundation McCarthy) f s1 = 1137.24 psf f s2 = 1121.48 psf After the pile is excavated, it's observed that there is no soil stuck in the pile channel in some distance near the ground surface. Then it's assumed that from the soil surface t o the unplugged distance only the outside flange areas are in contact with soil. The unplugged distance is observed to be about 0.3ft The pile used for the test is W4*13 pile, then the perimeter of the pile is 2.06 ft

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71 the width of the flange is 0.338 ft S ection area is 0.0266 ft 2 The side friction bearing capacity for each pile will need to be divided in 3 separate section Section 1: Unplugged contact area, and unit adhesion f s1 Section 2: Plugged contact area, and unit adhesion f s1 Section 3: Plugged contact area, and unit adhesion f s2 Nominal capacity for Pile no. (1) Pile penetration depth: 4.08 ft Q (Skin friction) (1) = fs1 *As (Unplugged) = (0.3*0.338*2) *1137.24 = 230.63 lbs Q (Skin friction) (2) = fs1 *As (Unplugged) = (3 0.3)*2.06 *1137.24 = 6325.3 lbs Q (Skin friction) (3) = fs2 *As (plugged) = (4.08 3)*2.06 *1121.48 = 2495.1 lbs Q (end bearing) = qb *Ab Q (end bearing) = 9*2803.7*0.0266 Q (end bearing) = 671.2 lbs Qult = ((230.63 +6325.3 +2495.1) + 671.2)/1000 Qult = 9.72 Kips

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72 Nominal capacity for Pile no. (2) Pile penetration depth: 3.88 ft Q (Skin friction) (1) = fs1 *As_unplugged = (0.3*0.338*2) *1137.24 = 230.63 lbs Q (Skin friction) (2) = fs1 *As_plugged = (3 0.3)*2.06 *1137.24 = 6325.3 lbs Q (Skin friction) (3) = fs2 *As_plugged = (3.88 3)*2.06 *1121.48 = 2033.1 lbs Q (end bearing) = qb *Ab = 9*2803.7*0.0266 = 671.2 lbs Qult = ((230.63 +6325.3 +2033.1) + 671.2)/1000 Qult = 9 .26 Kips Nominal capacity for Pile no. (3&4) Pile penetration depth: 4.0 ft Q (Skin friction) (1) = fs1 *As_unplugged = (0.3*0.338*2) *1137.24

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73 = 230.63 lbs Q (Skin friction) (2) = fs1* As_plugged = (3 0.3)*2.06 *1137.24 = 6325.3 lbs Q (Skin friction) (3) = fs2 *As_plugged = (4.0 3)*2.06 *1121.48 = 2310.2 lbs Q (end bearing) = qb *Ab = 9*2803.7*0.0266 = 671.2 lbs Qult = ((230.63 +6325.3 +2310.2) + 671.2)/1000 Qult = 9.53 Kips Nominal capacity for Pile no. ( 5) Pile penetration depth: 3.83 ft Q (Skin friction) (1) = fs1 *As_unplugged = (0.3*0.338*2) *1137.24 = 230.63 lbs Q (Skin friction) (2) = fs1 *As_plugged = (3 0.3) *2.06 *1137.24 = 6325.3 lbs Q (Skin friction) (3) = fs2 *As_plugged = (3.83 3)*2.06 *1121.48

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74 = 1917.5 lbs Q (end bearing) = qb *Ab = 9*2803.7*0.0266 = 671.2 lbs Qult = ((230.63 +6325.3 +1917.5) + 671.2)/1000 Qult = 9.14 Kips 5.2 Compariso n between the nominal capacity and STL result Table 10 : Comp arison of nominal capacity and SLT (Chang et. al, 2018) Pile Nominal Capacity [kips] (Using method) SLT Capacity [kips] 1 9.72 10.69 2 9.26 8.08 3 9.53 9.23 4 9.53 10.77 5 9.14 8.95 5.3 Discussion of the result For all piles, the nominal capacity (Using method) deviates not too much from the measured SLT. Pile #2 was tilled during the pile driving before the SLT, which may explain why the measured SLT capacity is much smaller than the nominal capacity . And as we know that the nominal ca pacity all based on assumptions so it will deviate from the test result which is the true capacity.

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75 6. Finite Element Analysis This chapter aims to use Finite Element method to analyze the response of a pile driven in a clay soil under the effect of static load testing. Nowadays, the use of finite element method based programs in structural and geotechnical analyses is generalized . These are particularly useful in study 3D Linear behavior on a driven pile. In this chapter, the finite element method compared to the results found from Static Lo The purpose is to obtain curves of the load settlement, End bearing, side shear distribution and total shear along the pile, traced from the results provided by the finite element program. 6.1 Pile analysis with SSI3D Program SSI3D used in my Finite Element Analysis, this software used to analyze soil structure interaction. A general purpose computer software, SSI3D was selected to serve the purpose. SSI3D was developed by Dr. Hien Nghiem at CGES, enhanced a fter joining the Hanoi Architectural University. This program will be further tested for their effectiveness in finite element analyses of geotechnical problem. The calibration of SSI3D concluded it is being an effective numerical modeling computer code an d it was selected for this study. The Model The analyzed piles are H pile and the loading is performed axially. These conditions allow for the use of symmetry; thus, the single piles behavior is modelled in three dimensions, using axisymmetric. 8 joints of solid elements are used to create the mesh. soil thickness below the pile tip is 0.3 m. Soil sizes are: 0.58x0.6 m

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76 Figure 6.1: Soil and Pile Model using SSI3D 6 ft

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77 Figure 6.2: Soil and Pile Geometry using SSI3D

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78 The pile and surrounding soil were modeled 3D Linear behavior . Three cases of pile were used depends on the penetration depth of the pile (46in, 48in, and 49in) to study the pile capacity. And I assumed that the rest of the pile have the same soil properti es. The result of the Finite Element represented by the load displacement behavior of the piles and compare it to the values computed and found from Static Load Test. Also, the results of the analysis were by the capacity of the piles, end bearing by the tip of the pile, side shear and total shear distribution along the pile all going to be presented in this chapter. Linear Elastic Model : The model s represent elastic stiffness parameters. ( ), and modulus (E). The linear elastic model is trying to simulate behavior of the soil . It is primarily used for stiff structural driven in the soil, such as the test pile in this thesis. Mohr Coulomb Model : This well known mode l is used to approximate behavior of soil . Due to its simplicity, it gives reasonable results and it is so popular. The model involves parameters like Undrained shear Strength, Cu. All the parameters were chosen based on the soil test result. After input all the properties in to the program as shown in table 11. The program run to load of 100 KN.

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79 6.2 Results and conclusion Table 11: Properties and units used in Finite Element Analysis W4*13 Pile Properties Area=3.83 in² = 0.0266 ft² Depth=4.16 in Width (bf)=4.06 in Thickness (tw)=0.280 in Length of pile = 6 ft = 72 inch = 1.8 m soil thickness below the pile tip = 0.3 m Soil = 0.58 x 0.6 m Poisson's Ratio = 0.2 young's Modulus= 200000000 psf Soil Properties Poisson's Ratio = 0.3 Young s Modulus = 2500 Undrained Shear Strength = 100 Kpa Total Load applied = 100 KN Thickness for each layer Pile #1 Pile #2 Pile #3 Layer 1 = 0.8 m Layer 1 = 0.8 m Layer 1 = 0.8 m Layer 2 = 0.1 m Layer 2 = 0.1 m Layer 2 = 0.1 m Layer 3 = 0.1 m Layer 3 = 0.1 m Layer 3 = 0.1 m Layer 4 = 0.55 m Layer 4 = 0.48 m Layer 4 = 0.52 m Length m , ft, in Area m² , ft 2 , in 2 Force KN , Kips

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80 Figure 6.3: Side shear Distribution along the pile (Pile#1) Figure 6.4: Total Side Shear and load transfer from pile to soil (Pile#1) 0 10 20 30 40 50 60 0 2 4 6 Depth (in.) Side Shear Distribution (psi) 0 10 20 30 40 50 60 0 2 4 6 8 10 12 Depth (in.) Total Side Shear (Kips)

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81 Figure 6.5: Side shear Distribution along the pile (Pile#2 and pile#5) Figure 6.6: Total Side Shear and load transfer from pile to soil (Pile#2 and pile #5) 0 5 10 15 20 25 30 35 40 45 50 0 2 4 6 Depth (in.) Side Shear Distribution (psi) 0 5 10 15 20 25 30 35 40 45 50 0 2 4 6 8 10 12 Depth (in.) Total Shear Stress (kips)

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82 Figure 6.7: Side shear Distribution along the pile (Pile#3 and pile #4) Figure 6.8: Total Side Shear and load transfer from pile to soil (Pile#3 and pile #4) 0 10 20 30 40 50 60 0 2 4 6 Depth (in.) Side Shear Distribution (psi) 0 10 20 30 40 50 0 2 4 6 8 10 12 Depth (in.) Total Side Shear (Kips)

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83 For the side shear distribution along the pile, so the curves represent the pile after have been driven in the soil al ready to a depth around (50 in. ) after applying the SLT on the pile while is it embedded in the soil and fail already, so the side shear increase s with depth to a point that it fails or the end bearing took a place at the depth of 40 in. and above. And the total side shear is the integration of the side shear distribution along the pile, it increases with depth, and it is accumulating quantity an d at depth around 50 inch it reaches the total side shear.

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84 Figure 6.10 : End bearing Capacity Curve On the tip of the pile (Pile#1) Figure 6.11 : End bearing Capacity Curve On the tip of the pile (Pile#3 and pile #4) 0 0.5 1 1.5 2 2.5 3 3.5 0 2 4 6 8 10 12 14 16 End Bearing Capacity (Kips) Load (Kips) 0 0.5 1 1.5 2 2.5 3 3.5 4 0 2 4 6 8 10 12 14 16 End Bearing Capcity (Kips) Load (Kips)

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85 Figure 6. 12 : End bearing Capacity Curve On the tip of the pile (Pile#2 and pile #5) F or the end bearing capacity it shows in top graphs the failure at a load around 2.4 kips for pile number (1), failure at a load around 2 kips for piles (3 and 4), and failure at a load around 2.16 kips for piles (2 and 5). Table 12: side shear, end bearing and total capacity from FEA Pile number Side shear (Kips) End Bearing (Kips) Total Ca pacity (Kips) 1 10.32 2. 20 12.52 2 1 0.2 2.15 1 2.3 3 1 0.55 2.13 12.7 0 0.5 1 1.5 2 2.5 3 3.5 4 0 2 4 6 8 10 12 14 16 Endbearing (Kips) Load (Kips)

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86 Figure 6. 1 3 : Load Experienced in the pile (Pile#1) Figure 6.14 : Load Experienced in the pile (Pile#2 and pile #5) 0 5 10 15 20 25 30 35 40 45 50 0 5 10 15 Depth (in.) Force (Kips) 0 5 10 15 20 25 30 35 40 0 5 10 Depth (in.) Load (Kips)

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87 Figure 6.15 : Load Experienced in the pile (Pile#3 and pile #4) For the force Vs. depth graphs shows the force transfer to the pile and as we go deep the force decrease with depth, which is normal as we go deeper the load start transfers and separate into the soil, and as we go to the bottom it reaches zero or cl ose to zero, then the load transfers from pile to soil. And the curve bellow shows the Force transfer to the pile for pile #5 (instrumented pile) from the analysis and the test. And as we see there is only 3 reading from strain gauge position 3, 4, and 5 b ecause it gives a reliable reading while we neglected the reading from strain gauge at the top (position 6) gives very high reading because when the point close to the end of the pile the reading will not going to be reliable because of the Saint Venent ef fect so the reading neglected for this strain gauge. And the bottom two reading was neglected also readings from (position 1 and 2) it gives high readings and unreal readings because the bottom two strain gauges were destroyed during the pile driving. 0 5 10 15 20 25 30 35 40 45 50 0 5 10 15 Depth (in.) Force (Kips)

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88 Figure 6.16 : Load Experienced in the pile (Pile#5) from analysis and test 0 5 10 15 20 25 30 35 40 45 50 0 5 10 15 Depth (in.) Force (Kips) Force from Analysis Force From Test

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89 Figure 6. 17 : Load and Settlement Curve (Pile#1) Figure 6. 18 : Load and Settlement Curve (Pile#3 and pile #4) 0 2 4 6 8 10 12 14 16 0.00E+00 1.00E-01 2.00E-01 3.00E-01 4.00E-01 5.00E-01 6.00E-01 7.00E-01 Load (Kips) Settlement (in.) 0 2 4 6 8 10 12 14 0 0.1 0.2 0.3 0.4 0.5 0.6 Load (Kips) Settlement (in.)

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90 Figure 6. 19 : Load and Settlement Curve (Pile#2 and pile #5 Instrumented pile) For the Load / Settlement curves the settlement start to increase by applying the load until it reach almost 12 kips and it start to flatten up that shows that it fails with total bearing c apacity equals to (around 12) 0 2 4 6 8 10 12 14 0.00E+00 1.00E-01 2.00E-01 3.00E-01 4.00E-01 5.00E-01 6.00E-01 7.00E-01 8.00E-01 9.00E-01 Load (Kips) Settlement (in.)

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91 Figure 6. 20 : Load and Displacement Curve (Pile#1) Figure 6. 21 : Load and Displacement Curve (Pile#3 and 4) -2 0 2 4 6 8 10 12 14 -5.00E-02 0.00E+00 5.00E-02 1.00E-01 1.50E-01 2.00E-01 2.50E-01 Load (Kips) Displacement (in.) Pile #1 (Analysis) Pile #1 (Test) -2 0 2 4 6 8 10 12 14 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 Load (Kips) Displacement (in.) Pile #3 and #4 (Analysis) Pile #3 (Test) Pile #4 (Test)

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92 Figure 6. 22 : Load and Displacement Curve (Pile#2 and #5) The results from the Finite Element Analys is is deferent from the test results. This probably due to the reason that Mohr Coulomb model is applied to simulate the behavior of the soil layer, compare to the soil behavior in the Static Load Test. The Mohr Coulomb is an elastic perfectly plastic mode l with fixed yield surface. On the other hand, in the testing the loading on the soil with real soil parameters will act different. And the simulation of the soil parameters will effect also. Because for soil testing there is some disturbance to the soil s It is well known that conventional static load test has inherent disadvantages. The influence of reaction system may be reduced by increasing the spacing between test pile and reaction pile however, it is not always achieved when the working space is restrained. Besides, the interpretation of the data obtained from tests is not straightforward as it is not easy to separate the shaft resistance from the end bearing capacity especially because the bottom strain gauges where des troyed during the driving. -2 0 2 4 6 8 10 12 14 -2.00E-01 0.00E+00 2.00E-01 4.00E-01 6.00E-01 8.00E-01 1.00E+00 Load (Kips) Displacement (in.) Pile #2 and #5 (Analysis) Pile #5 (Test) Pile #2 (Test)

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93 So, I re properties will effect on the result and it was right it did effect the result and almost match the test result for the Load/Settlement curve. And the graphs below shown the Load/Settlement with Figure 6. 23 : Load and Displacement Curve (Pile#1) -2 0 2 4 6 8 10 12 14 -2.00E-02 0.00E+00 2.00E-02 4.00E-02 6.00E-02 8.00E-02 1.00E-01 1.20E-01 1.40E-01 1.60E-01 1.80E-01 Load (Kips) Displacement (Inch) Pile #1 (Analysis) Pile #1 (Test)

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94 Figure 6. 24 : Load and Displacement Curve (Pile#2 and #5) Figure 6. 25 : Load and Displacement Curve (Pil e#3 and 4) -2 0 2 4 6 8 10 12 14 -1.00E-01 0.00E+00 1.00E-01 2.00E-01 3.00E-01 4.00E-01 5.00E-01 6.00E-01 Load (Kips) Displacement (Inch) Pile #3 and #4 (Analysis) Pile #3 (Test) Pile #4 (Test) -2 0 2 4 6 8 10 12 14 -1.00E-01 0.00E+00 1.00E-01 2.00E-01 3.00E-01 4.00E-01 5.00E-01 6.00E-01 7.00E-01 Load (Kips) Displacement (inch) Pile #2 and #5 (Analysis) Pile #5 (Test) Pile #2 (Test)

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95 Back Calculating Nc After finding Qt and Qs, Qb can be found from (6.1) (6.2) Then, (6.3) C u = Undrained shear strength at the tip of the pile Q b = End Bearing capacity A b = whole rectangular tip area d 1 = 4.16 in d 2 = 4.06 in For the calculations in the table below, at first I used the cross section area of the piles which is equal to (3.83 in 2 ) but it gives really high Nc (more than 20). So, I tried the whole rectangular tip area and it did give a reasonable value of Nc

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96 Table 12: Nc Value for each pile Pile Number Nc 1 7 2 ,5 6.9 3 ,4 6.8 Nc Ave.

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97 7. Bias Factor The load, resistance bias factor is defined as: Bias factor (or bias) is typically defined as ratio of the measured value divided by the nominal (predicted) value and in our case it defined as the ratio of the measured true capacity by the nominal capacity. (7.1) Where : R m = measured resistance, Q m = measured load R n = predicted resistance, Q n = predicted load Table 1 3 : Comparison between SLT and nominal capacity (Chang et. al, 2018) Pile SLT Capacity (kips) Nominal Capacity (kips) Bias Factor ( ) Nominal Capacity (Kips) (Using FEA) Bias Factor ( ) 1 10.69 9.72 1.10 12.52 0.86 2 8.08 9.26 0.87 12.3 0.69 3 9.23 9.53 0.97 12.7 0.72 4 10.77 9.53 1.13 12.7 0.9 5 8.95 9.14 0.98 12.3 0.8 Pile 2 experienced some problem and tilted during the driving process before Static Load Test .

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98 8. Summary, Conclusions, and future studies Summary and Conclusion, The large scale SLT delivers the total capacity of W4/13 pile driven into medium hard Leyden clay is about 9 kips. The measured loads from SGs are, in general, for the strain gauge s should be followed to avoid the strain gauges from getting destroyed because of the driving process. The cap were destroyed at these positions. The distribution of undrained shear strength with depth from both QU and UU tests were summarized in (Figure: 3.9) . UU test was the test that foll owed in this project, because the qu test values were to small and the UU test was more reliable. Moisture content in the future should me more controlled, even the placement of the soil in side the tiger cage should be controlled in better way and faster as possible. Sampling procedure should be improved, and try not to lose samples. To get reliable evaluation for the Undrained shear strength of the soil. For all piles, the nominal capacity deviates not too much from the measured SLT. Pile #2 was tilled during the pile driving before the SLT, which may explain why the measured SLT capacity is much smaller than the nominal capacity. A s we kn ow that the nominal capacity based on assumptions so it will deviate from the test result which is the true capacity. S ide shear increases with depth to a point that it fails or the end bearing took a place at the depth of 40 inches and above. And the total side shear is the int egration of the side shear distribution along the pile, it increases with depth, and it is accumulating quantity and at depth around 50 inch it reaches the total side shear.

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99 For the end bearing capacity it shows in top graphs the failure at a load around 2.4 kips for pile number (1), failure at a load around 2 kips for piles (3 and 4), and failure at a load around 2.16 kips for piles (2 and 5). For the force Vs. depth graphs shows the force transfer to the pile and as we go deep the force decrease with d epth, which is normal as we go deeper the load start transfers and separate into the soil, and as we go to the bottom it reaches zero or close to zero, then the load transfers from pile to soil. Because of the strain gauges that destroyed, we can see from the curves of Force Vs. Depth the End bearing. For the Load / Settlement curves the settlement start to increase by applying the load until it reach almost 12 kips and it start to flatten up that shows that it fails with total bearing capacity equals to (around 12) The deviation between the Finite Element analysis and the test is that the input of the soil properties values make s big change in the results . Even for SLT, so many factors affect the test procedure that could change the results or makes it not reasonable, like what happened to Pile 2 experienced some problem and tilted during the driving process before Static Load Test. And the strain gauges that we lost during the driving process and affect the reading and the data. the future we can get better results.

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100 Table 14: Comparision between the Capacities from calculations, test and Analysis Pile Nominal Capacity [kips] Nominal Capacity from FEA [kips] SLT Capacity [kips] 1 9.72 12.4 10.69 2 9.26 11.6 8.08 3 9.53 11.9 9.23 4 9.53 11.9 10.77 5 9.14 11.6 8.95

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101 For future study , New design for pile instrumentation recommended Figure 8.1 : New design for pile instrumentation (Chang et. al, 2018) Solder spot is removed in new design, the SG wire is now connect ed directly with the leads and solder spot is isolated by heat shrink cable to avoid any continuity. In new design, a steel U shaped cover is weld directly to the pile web to protect the instrumentation. Hence all the deficiency in the old design are overcome with this new design. Moreover, this design also can b e extended to field test easily.

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102 References Nien Yin Chang, P.E., Ph.D. and Hien Manh Nghiem, Ph.D. Yail Jimmy Kim, P.E., Ph.D. (2017) Driven Pile LRFD Resistance Factor Calibration using Pile Bent Static Load Tests with Embedded Data Collector: Phase I Laboratory Large Scal e Allen, Tony M. , 2005 Development of the WSDOT Pile Driving Formula and Its Calibration and Resistance Factor Design (LRFD), FHWA Report, WA RD 610.1, Washington State Department of Transportation. Chang, N.Y., 2006 CDOT Foundation Design Practice and LRFD Strategic Plan, Report No. CDOT DTD R 7 . Department of the Army U.S. Army Corps of Engineers Washington, 15 January 1991 DC 20314 1000 EM 1110 2 2906 ENGINEERING AND DESI GN OF PILE FOUNDATIONS . of Practice, No. 17, American Society of Civil Engineers, New York . Hasa nzoi Marwa, M.S. Thesis University of Pittsburgh, 2015 CAPACITY AND DRIVEABILI TY ASSESSMENT OF 50 KSI H PILES . Davisson, M.T., 1972, High Capacity Piles, Proceedings of the Lecture Series on Innovation in Foundation Construction, pp. 81 112, ASCE Illinois Section, Chicago, IL. Cuong Vu, 2013, Ph.D Dissertation, Geological dependence of resista nce factors for deep foundation. Federal Highway Administration (FHWA) (1998). Driven Manual. Mathias, D. and Cribbs, M. Blue Six Software, Inc. Logan, UT. Ryan Belbas 2013 The Capacity of Driven Steel H Piles in Lacustrine Clay, Till and Karst B edrock: A Winnipeg Case Study University of Manitoba Winnipeg .

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103 Nien Yin Chang, Robert Vinopal, Cuong Vu, Hien Nghiem August 2011 . CDOT STRATEGIC PLAN FOR DATA COLLECTION AND EVALUATION OF GRADE 50 H PILES INTO BEDROCK Report No. CDOT 2011 11 M. S. Rahman, Ph.D., P.E., Professor M. A. Gabr, Ph.D., P.E., Professor R. Z. Sarica July 28, 2002 . Load and Resistance Factor Design (LRFD) for Analysis/Design of Piles Axial Capacity Graduate Assistant M. S. Hossain, Graduate Assistant Department of Civil, Construction and Environmental Engineering North Carolina State University Final Report Raleigh, North Carolina U.S. Department of Trans portation Federal Highway Administration Publication September 2016 . No. FHWA NHI 16 009 FHWA GEC 012 Volume I. Paikowsky, S. G. 2004 . Load and Resistance Factor Design (LRFD) for Deep Foundations, NCHRP Report 507, Transportation Research Board, Washin gton, DC. Sci entific and Technical, England. AASHTO (2014) . AASHTO LRFD Bridge Design Specifications, 7th edition, American Association of State Highway and Transportation O fficials, Washington DC . AASHTO (2010) . AASHTO LRFD Bridge Design Specifications, 5th edition and interims, American Association of State Highway and Transportation Officials, Wa shington DC. U.S. Department of Transportation December , 2006 . Publication No. FHWA NHI 06 088 Federal Highway Administration NHI Course No. 1 32012 SOILS AND FOUNDATIONS. Bowles, J. , 1996 . Foundation Analysis and Design. McGraw Hill, New York. Kyung Jun Kim 2002, PhD thesis, DEVELOPMENT OF RESISTANCE FACTORS FOR AXIAL CAPACITY OF DRIVEN PILES IN NORTH CAROLINA.

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104 Das, B. (2010) , Principles of Foundation Engineering, 7e, Cengage Learning . U.S. Army Corps of Engineers , 1992 . Bearing Capacity of Soil. Technical Engineering and Design Guides, No. 7, EM 1110 1 1905. Adapted by ASCE 2000. ASCE Press, New York. Reese, L.C., Wang, S.C. and Isenhower, W.M. , 2006 , Analysis and Design of Shallow and Deep Foundation. John Wiley and Sons Ltd. Terzaghi, K., and Peck, R.B. (1967). Soil Mechanics in Engineering Practice. Wiley