The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Ruwan Rajapakse - One of the best experts on this subject based on the ideXlab platform.
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Pile Design: Special Situations
Pile Design and Construction Rules of Thumb, 2020Co-Authors: Ruwan RajapakseAbstract:The chapter discusses Pile Design. It begins with the discussion of timber Pile Design, in which the engineer needs to make sure that the timber is of good sound quality, free from decay, and without damage during transportation and insect attack. Timber Piles contain knots and need to be observed. Local codes may provide guidelines on acceptable and nonacceptable knots. Acceptable knot size is dependent on the type of timber. The chapter discusses a case study on bridge Pile Design. It also discusses the auger cast Pile Design, in which the bearing capacity is low compared with that of size-driven Piles. The volume of grout depends on the applied pressure. If grout is pumped at a higher pressure, more volume of grout will be pumped. In most cases, the volume of grout pumped is more than the volume of the hole. The chapter provides a case study which illustrates the comparison between bored Piles and driven Piles.
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42 – Pile Design in clay soils
Geotechnical Engineering Calculations and Rules of Thumb, 2020Co-Authors: Ruwan RajapakseAbstract:This chapter discusses Pile Design in clay soils. Pile capacity in clay soils depends on end bearing and skin friction. End bearing capacity and skin friction depends on cohesion of soil and effective stress. Adhesion between Pile and soil is an important concept as well.
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Pile Design software
Pile Design and Construction Rules of Thumb, 2020Co-Authors: Ruwan RajapakseAbstract:This chapter discusses Pile Design software. Most geotechnical engineering softwares are based on the finite element method, which is considered to be the most powerful mathematical method today for solving piling problems. Any type of soil condition can be simulated using the finite element method. Computer programs are available with finite element platforms. These programs can be used to solve a wide array of piling problems. The user is expected to have a working knowledge of finite element analysis to use these programs. More specialized computer programs are also available in the market. These programs do not require knowledge of finite element analysis. The boundary element method, a simplified version of the finite element method, considers only the elements at boundaries. The chapter also describes lateral loading analysis.
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20 – Pile Design Software
Pile Design and Construction Rules of Thumb, 2020Co-Authors: Ruwan RajapakseAbstract:Publisher Summary This chapter discusses Pile Design software. Most geotechnical engineering softwares are based on the finite element method, which is considered to be the most powerful mathematical method today for solving piling problems. Any type of soil condition can be simulated using the finite element method. Computer programs are available with finite element platforms. These programs can be used to solve a wide array of piling problems. The user is expected to have a working knowledge of finite element analysis to use these programs. More specialized computer programs are also available in the market. These programs do not require knowledge of finite element analysis. The boundary element method, a simplified version of the finite element method, considers only the elements at boundaries. The chapter also describes lateral loading analysis.
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Geotechnical Engineering Calculations and Rules of Thumb - Pile Design in sandy soils
Geotechnical Engineering Calculations and Rules of Thumb, 2020Co-Authors: Ruwan RajapakseAbstract:This chapter analyzes the Design of Piles in sandy soils. A modified version of the Terzaghi bearing capacity equation is widely used for Pile Design. When a Pile is driven, the effective stress of the existing soil around and below the Pile changes. The effective stress prior to and after driving the Pile is shown. Many researchers have provided techniques to compute bearing capacity factors. The end bearing capacity is a function of friction angle, dilatancy of soil, and relative density Different methods of obtaining the bearing capacity factor value are elaborated. It is necessary to investigate lateral earth pressure coefficients in general. An equation based on the SPT (N) value is proposed to compute the ultimate end bearing capacity of driven Piles. Equation based on the SPT (N) value to compute the ultimate end bearing capacity of driven Piles. Various reasons have been put forward to explain reasons that skin friction does not increase with depth indefinitely as suggested by the skin friction equation. Pile end bearing capacity in sandy soils is related to effective stress. Experimental data indicates that end bearing capacity does not increase with depth indefinitely. Engineers use the same critical depth concept adopted for skin friction for end bearing capacity as well.
Muhammed Vefa Akpinar - One of the best experts on this subject based on the ideXlab platform.
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Information Systems and Artificial Intelligence Technology Applied in Numerical Design Stage of Deep Foundation Systems
2020Co-Authors: Erhan Burak Pancar, Muhammed Vefa AkpinarAbstract:In this paper, the main objective is to show how to obtain precise Pile Design by using an information system and artificial intelligence (ISAI) applied in the numerical Design stage of a deep foundation system. In this system, real parameters of soil layers are used and axial effect coming into the Pile is taken into account. In this paper, a numerical solution is determined according to the principles of Pile Design by using an electronic interior control subsystem. In this deterministic approach, intelligent object (IO) with a dz thickness moves forward through the soil layers. Diameter, length and steel ratio are determined by the system through numerical solution. As a result, a precise solution for Pile diameter, Pile length and steel ratio can be determined directly. The system incorporates ISAI technology. Keywords—Deep foundation, Pile Design, Information Systems and Artificial Intelligence Technology
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Information Systems and Artificial Intelligence Technology Applied in Pile Design
International Journal of Artificial Intelligence and Knowledge Discovery, 2011Co-Authors: Erhan Burak Pancar, Muhammed Vefa AkpinarAbstract:In this paper, the main objective is to show how to obtain precise Pile Design by using an information systems and artificial intelligence (ISAI) applied in the numerical Design stage of a deep foundation system. In this system, real parameters of soil layers are used. Axial effect and then all effects coming into the Pile are taken into account in given examples. In this paper, a numerical solution is determined according to the principles of Pile Design by using an electronic interior control subsystem. In this deterministic approach, intelligent object (IO) with a dz thickness moves forward through the soil layers. This Diameter, length and steel ratio are determined by the system through numerical solution. As a result, a precise solution for Pile diameter, Pile length and steel ratio can be determined directly. The system incorporates ISAI technology.
S. P. G. Madabhushi - One of the best experts on this subject based on the ideXlab platform.
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A critical review of methods for Pile Design in seismically liquefiable soils
Bulletin of Earthquake Engineering, 2008Co-Authors: S. Bhattacharya, S. P. G. MadabhushiAbstract:Collapse and/or severe damage to Pile-supported structures are still observed in liquefiable soils after most major earthquakes. Poor performance of Pile foundations remains a great concern to the earthquake engineering community. This review paper compares and contrasts the two plausible theories on Pile failure in liquefiable soils. The well established theory of Pile failure is based on a flexural mechanism; where the lateral loads on the Pile (due to inertia and/or lateral spreading) induce bending failure. This theory is well researched in the recent past and assumes that Piles are laterally loaded beams. A more recent theory based on buckling instability treats the Piles as laterally unsupported slender columns in liquefiable soils and investigates the buckling instability (bifurcation). The objective of this paper is to investigate the implications to practical Pile foundation Design that flow from both these theories. Provisions for Design made by major international codes of practice for Pile Design including the Japanese Highway Code (JRA) will be considered. The necessity for such codes to consider alternative forms of failure mechanisms such as the buckling instability of Piles in liquefied ground will be discussed.
Johan V. Retief - One of the best experts on this subject based on the ideXlab platform.
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Pile Design practice in southern Africa : part 1 : resistance statistics : technical paper
Joernaal van die Suid-Afrikaanse Instituut van Siviele Ingenieurswese, 2013Co-Authors: M. Dithinde, Johan V. RetiefAbstract:The paper presents resistance statistics required for reliability assessment and calibration of limit state Design procedures for Pile Design reflecting southern African practice. The first step of such a development is to determine the levels of reliability implicitly provided for in present Design procedures based on working stress Design. Such an assessment is presented in an accompanying paper (please turn to page 72). The statistics are presented in terms of a model factor M representing the ratio of Pile resistance interpreted from Pile load tests to its prediction based on the static Pile formula. A dataset of 174 cases serves as sample set for the statistical analysis. The statistical characterisation comprises outliers detection and correction of erroneous values, using the corrected data to compute the sample moments (mean, standard deviation, skewness and kurtosis) needed in reliability analysis. The analyses demonstrate that driven Piles depict higher variability compared to bored Piles, irrespective of materials type. In addition to the above statistics, reliability analysis requires the theoretical probability distribution for the random variable under consideration. Accordingly it is demonstrated that the log normal distribution is a valid theoretical model for the model factor. Another key asis for reliability theory is the notion of randomness of the basic variables. To verify that the variation in the model factor is not explainable by deterministic variations in the database, an investigation of correlation of the model factor with underlying Pile Design parameters is carried out. It is shown that such correlation is generally weak.
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Pile Design practice in southern Africa Part 2: Implicit reliability of existing practice
Journal of The South African Institution of Civil Engineering, 2013Co-Authors: Johan V. Retief, M. DithindeAbstract:Limit state Design has become the basis of geotechnical Design codes worldwide. With the semi-probabilistic limit state Design approach, load and resistance factors of (deterministic) Design functions are calibrated on the basis of reliability theory. The calibration is done to obtain procedures that will ensure that a target level of reliability is exceeded under the Design conditions within the scope of the Design function. This is conventionally expressed in terms of the reliability index (β), which is related to the probability of failure (P f ). Acceptable existing Design practice is an important source of information on appropriate levels of reliability. This paper uses the results from a Pile load test database to evaluate the reliability levels implied in the current South African Pile Design approach. The results of the analysis indicate that the reliability index values for ultimate limit state failure of single Piles implicit to present Design practice vary with the Pile class. However, the influence of the probability model applied is more significant. Based on conventional and standardised procedures for reliability analysis, a representative implicit reliability index value β I,Rep 3.5 is obtained, corresponding to a probability of failure P f = 2.10 -4 . The values for various sets of Pile conditions range from β I = 3.1 (Pf = 1.10 -3 ) to βI = 4.3 (Pf = 1.10 -5 ). This compares well with target levels of reliability for structural and geotechnical performance of β T = 3.0 as set in SANS 10160-1:2011 Part 1 Basis of structural Design. These indicative results provide a useful reference base to establish the reliability of existing and therefore acceptable South African Pile Design practice. It could also be interpreted as indicative of geotechnical Design practice in general. The standard SANS 10160-5:2011 Part 5 Basis for geotechnical Design and actions provides the framework for future calibration investigations.
M. Dithinde - One of the best experts on this subject based on the ideXlab platform.
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Pile Design practice in southern Africa : part 1 : resistance statistics : technical paper
Joernaal van die Suid-Afrikaanse Instituut van Siviele Ingenieurswese, 2013Co-Authors: M. Dithinde, Johan V. RetiefAbstract:The paper presents resistance statistics required for reliability assessment and calibration of limit state Design procedures for Pile Design reflecting southern African practice. The first step of such a development is to determine the levels of reliability implicitly provided for in present Design procedures based on working stress Design. Such an assessment is presented in an accompanying paper (please turn to page 72). The statistics are presented in terms of a model factor M representing the ratio of Pile resistance interpreted from Pile load tests to its prediction based on the static Pile formula. A dataset of 174 cases serves as sample set for the statistical analysis. The statistical characterisation comprises outliers detection and correction of erroneous values, using the corrected data to compute the sample moments (mean, standard deviation, skewness and kurtosis) needed in reliability analysis. The analyses demonstrate that driven Piles depict higher variability compared to bored Piles, irrespective of materials type. In addition to the above statistics, reliability analysis requires the theoretical probability distribution for the random variable under consideration. Accordingly it is demonstrated that the log normal distribution is a valid theoretical model for the model factor. Another key asis for reliability theory is the notion of randomness of the basic variables. To verify that the variation in the model factor is not explainable by deterministic variations in the database, an investigation of correlation of the model factor with underlying Pile Design parameters is carried out. It is shown that such correlation is generally weak.
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Pile Design practice in southern Africa Part 2: Implicit reliability of existing practice
Journal of The South African Institution of Civil Engineering, 2013Co-Authors: Johan V. Retief, M. DithindeAbstract:Limit state Design has become the basis of geotechnical Design codes worldwide. With the semi-probabilistic limit state Design approach, load and resistance factors of (deterministic) Design functions are calibrated on the basis of reliability theory. The calibration is done to obtain procedures that will ensure that a target level of reliability is exceeded under the Design conditions within the scope of the Design function. This is conventionally expressed in terms of the reliability index (β), which is related to the probability of failure (P f ). Acceptable existing Design practice is an important source of information on appropriate levels of reliability. This paper uses the results from a Pile load test database to evaluate the reliability levels implied in the current South African Pile Design approach. The results of the analysis indicate that the reliability index values for ultimate limit state failure of single Piles implicit to present Design practice vary with the Pile class. However, the influence of the probability model applied is more significant. Based on conventional and standardised procedures for reliability analysis, a representative implicit reliability index value β I,Rep 3.5 is obtained, corresponding to a probability of failure P f = 2.10 -4 . The values for various sets of Pile conditions range from β I = 3.1 (Pf = 1.10 -3 ) to βI = 4.3 (Pf = 1.10 -5 ). This compares well with target levels of reliability for structural and geotechnical performance of β T = 3.0 as set in SANS 10160-1:2011 Part 1 Basis of structural Design. These indicative results provide a useful reference base to establish the reliability of existing and therefore acceptable South African Pile Design practice. It could also be interpreted as indicative of geotechnical Design practice in general. The standard SANS 10160-5:2011 Part 5 Basis for geotechnical Design and actions provides the framework for future calibration investigations.