scholarly journals Reliability analysis of an end-bearing pile with account for friction forces on the pile surface

2020 ◽  
pp. 2-2
Author(s):  
Vladimir S. Utkin
Keyword(s):  
Bearing Capacity ◽  
Reliability Analysis ◽  
Limit State ◽  
Soil Layer ◽  
Material Behavior ◽  
Performance Criteria ◽  
Soil Behavior ◽  
Foundation Soil ◽  
Friction Forces ◽  
End Bearing Pile

Introduction. The behavior of end-bearing piles in the foundation soil and the methodology for their reliability analysis, treated as operational safety measures applicable to a separate bearing element of a pile foundation, need clarification and further development. The weakness of the established reliability analysis methodology, focused on the bearing capacity of the foundation soil, is its failure to take account of each case of the soil behavior above rock or low compressibility soils pursuant to Construction rules and regulations 24.13330.2011. Taking account of the bearing capacity of this soil layer in respect of the load accommodation by an end-bearing pile (taking account of the pile weight) may improve its reliability by the criterion of the bearing capacity in combination with the soil behavior below the bottom tip of a pile. Nizhne-Suyanskiy Waterworks Facility had the mission to solve water household, energy and socio-economic problems. Materials and methods. The author analyzed piles made of any applicable materials; their reliability analysis methods are based on the possibility theory due to the limited amount of statistical information on controllable parameters to be entered into the limit state design model to verify the bearing capacity of the foundation soil. Results. The author presents the design formula to identify the parameters ensuring reliable failure-free behavior of an end-bearing pile in the foundation soil and in respect of the soil bearing capacity. The pile reliability analysis performed in respect of its bearing capacity (and focused on the strength of the pile material) is provided in the references section. The author uses two performance criteria to analyze the reliability of an end-bearing pile, given that an end-bearing pile is analyzed as a consistent mechanical system in terms of the reliability theory. Conclusions. The author has developed a methodology used to analyze the reliability of end-bearing piles. It is focused on the bearing capacity of the foundation soil below the bottom tip of a pile and along its length with a view to the quantitative assessment of its safe performance at the stage of design of a facility that has a piled footing; the groundwork has been laid for further research into the behavior of end-bearing piles and for the development of design regulations applicable to various types of piles that may differ in material, behavior, sinking techniques, etc.

scholarly journals Bearing strength calculation of end-bearing piles under recognition of cohesive friction on the pile surface

2019 ◽  
pp. 1-1 ◽  
Author(s):  
Vladimir Utkin
Keyword(s):  
Bearing Capacity ◽  
Limit State ◽  
Soil Layer ◽  
Design Stage ◽  
Material Strength ◽  
Soil Base ◽  
Foundation Soil ◽  
Bearing Strength ◽  
Base Soil ◽  
End Bearing Pile

Introduction. It is a drawback of the existing end-bearing pile design method for soil base bearing capacity that the latter is not taken into account in the assessment of the foundation soil action above the rock or a low-compression soil layer in all cases in accordance with the Building Code 24.13330.2011. However, taking into account the bearing capacity of this layer of the soil base in the load accommodation by the end-bearing pile (under recognition of the pile weight) could increase its calculated bearing capacity by the respective value of the soil base bearing capacity in combination with the soil support action under the pile’s lower end. The objective of the research is improving the trustworthiness of the calculation result of the bearing strength of end-bearing piles in the soil base, identifying the pile’s bearing strength reserve by taking in account the additional soil base bearing capacity due to the cohesive friction on the side surface of the pile. Materials and methods. The object of the research are piles of any applicable materials. The methods of calculation of the end-bearing piles are based on on cohesive friction values and their distribution along the pile length in a limit state calculation model in terms of the soil base bearing capacity. Results. The paper presents the equation of the ultimate compression load of the end-bearing pile in terms of the foundation base soil bearing capacity and the formula for the base soil bearing capacity reserve factor of the pile. The calculation of the pile bearing strength in terms of the material strength is referenced in the bibliography. Conclusions. A calculation method of end-bearing piles bearing strength was developed based both on the bearing capacity of soil base under the pile lower end and the additional soil bearing capacity along the flanks of the pile. The method could be applied also for calculations of the bearing strength of deep slot-type foundations. A quantitative assessment of the end-bearing pile on the design stage of a building with a pile foundation is given, prerequisite is made for further studies of the action of end-bearing piles and development of design codes for various piles in terms of material, type of support action, methods of immersion in the soil, etc.

scholarly journals FRICTION PILE RELIABILITY ANALYSIS WITH RESPECT TO THE FOUNDATION SOIL BEARING CAPACITY

2019 ◽  
pp. 1-1
Author(s):  
Vladimir S. Utkin
Keyword(s):  
Bearing Capacity ◽  
Reliability Analysis ◽  
Limit State ◽  
Statistical Information ◽  
Material Strength ◽  
Limit States ◽  
Foundation Soil ◽  
Soil Layers ◽  
Friction Pile ◽  
Pile Operation

Introduction. Friction pile reliability under the action of the central compressing force according to the Set of Rules 24.13330.2011 is calculated from the first group of the limit states — from the bearing capacity (using the pile material strength criteria and the foundation soil bearing capacity criterion) and from the second group of the limit states — from the pile load-deformation behaviour. Materials and methods. A method of calculating the friction pile reliability from the foundation soil bearing capacity is considered. Reliability appears as a quantitative measure of safety of a single pile operation. The foundation soil bearing capacity is accepted as a criterion for the pile operating capacity. The pile reliability analysis is based on the statistical information obtained during the preliminary pile testing with measuring the friction on the surface of the pile placed in the soil layers and the soil stress under the pile foot. The testing methods for obtaining the statistical information were well-known and used earlier to generate the lists of f-values and R-values in the Set of Rules 24.13330.2011. Each random parameter is measured at least three times. Results. The theory of analysis of the preliminary pile reliability in accordance with GOST 27751-2014 “Reliability of building structures and foundations” has been built on this statistical information. Reliability as the calculation result is represented by interval notation. The mathematical model of the limit state of the pile from the foundation soil bearing capacity has been borrowed from the Set of Rules. The connection (formula) between the length of the pile and the value of its reliability as a safety measure for its operation in the foundation soil has been established. Evaluation of the friction pile reliability corresponding to the characteristic value is carried out by calculation (trail-and-error method) from the mechanical properties of the soil and the load on the pile with the indication of the value of the length of the pile or the sum of the soil layers, each of the values in this case shall be not more than 2 m. The reliability analysis is described in the case studies set out in the article. Conclusions. Pile reliability analysis is based on the actual information about the pile operation in the foundation soil according to the current regulations of the Russian Federation, so the proposed method of the friction pile reliability analysis can be transferred into practice. It can also be used in the reliability calculation for other load-bearing elements, in the regulatory literature, and in the academic work of construction universities.

scholarly journals FRICTION PILE RELIABILITY ANALYSIS WITH RESPECT TO THE FOUNDATION SOIL BEARING CAPACITY

2019 ◽  
pp. 1-1
Author(s):  
Vladimir S. Utkin
Keyword(s):  
Bearing Capacity ◽  
Reliability Analysis ◽  
Limit State ◽  
Statistical Information ◽  
Material Strength ◽  
Limit States ◽  
Foundation Soil ◽  
Soil Layers ◽  
Friction Pile ◽  
Pile Operation

Introduction. Friction pile reliability under the action of the central compressing force according to the Set of Rules 24.13330.2011 is calculated from the first group of the limit states — from the bearing capacity (using the pile material strength criteria and the foundation soil bearing capacity criterion) and from the second group of the limit states — from the pile load-deformation behaviour. Materials and methods. A method of calculating the friction pile reliability from the foundation soil bearing capacity is considered. Reliability appears as a quantitative measure of safety of a single pile operation. The foundation soil bearing capacity is accepted as a criterion for the pile operating capacity. The pile reliability analysis is based on the statistical information obtained during the preliminary pile testing with measuring the friction on the surface of the pile placed in the soil layers and the soil stress under the pile foot. The testing methods for obtaining the statistical information were well-known and used earlier to generate the lists of f-values and R-values in the Set of Rules 24.13330.2011. Each random parameter is measured at least three times. Results. The theory of analysis of the preliminary pile reliability in accordance with GOST 27751-2014 “Reliability of building structures and foundations” has been built on this statistical information. Reliability as the calculation result is represented by interval notation. The mathematical model of the limit state of the pile from the foundation soil bearing capacity has been borrowed from the Set of Rules. The connection (formula) between the length of the pile and the value of its reliability as a safety measure for its operation in the foundation soil has been established. Evaluation of the friction pile reliability corresponding to the characteristic value is carried out by calculation (trail-and-error method) from the mechanical properties of the soil and the load on the pile with the indication of the value of the length of the pile or the sum of the soil layers, each of the values in this case shall be not more than 2 m. The reliability analysis is described in the case studies set out in the article. Conclusions. Pile reliability analysis is based on the actual information about the pile operation in the foundation soil according to the current regulations of the Russian Federation, so the proposed method of the friction pile reliability analysis can be transferred into practice. It can also be used in the reliability calculation for other load-bearing elements, in the regulatory literature, and in the academic work of construction universities.

Response surface method strategies coupled with NLFEA for structural reliability analysis of prestressed bridges

2021 ◽  
Author(s):  
Silvia J. Sarmiento Nova ◽  
Jaime Gonzalez-Libreros ◽  
Gabriel Sas ◽  
Rafael A. Sanabria Díaz ◽  
Maria C. A. Texeira da Silva ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Response Surface ◽  
Response Surface Method ◽  
Structural Reliability ◽  
Limit State ◽  
Material Behavior ◽  
Nonlinear Material ◽  
State Function ◽  
Surface Method ◽  
Highly Nonlinear

<p>The Response Surface Method (RSM) has become an essential tool to solve structural reliability problems due to its accuracy, efficacy, and facility for coupling with Nonlinear Finite Element Analysis (NLFEA). In this paper, some strategies to improve the RSM efficacy without compromising its accuracy are tested. Initially, each strategy is implemented to assess the safety level of a highly nonlinear explicit limit state function. The strategy with the best results is then identified and used to carry out a reliability analysis of a prestressed concrete bridge, considering the nonlinear material behavior through NLFEA simulation. The calculated value of &#120573; is compared with the target value established in Eurocode for ULS. The results showed how RSM can be a practical methodology and how the improvements presented can reduce the computational cost of a traditional RSM giving a good alternative to simulation methods such as Monte Carlo.</p>

Evaluating the Bearing Capacity of a Soil Layer Overlying Rigid Substratum Using a Modified Failure Mechanism Based on Limit State Analysis

2013 ◽  
Vol 353-356 ◽  
pp. 806-814
Author(s):  
Reza Afshar-Mazandaran ◽  
Hadi Khabbaz
Keyword(s):  
Bearing Capacity ◽  
Failure Mechanism ◽  
Limit State ◽  
Soil Layer ◽  
Finite Depth ◽  
Bound State ◽  
Shallow Foundations ◽  
Collapse Mechanism ◽  
Parametric Studies ◽  
Spiral Surface

The bearing capacity of shallow foundations resting on a soil layer with a finite depth over bedrock has been studied for years by many investigators. Farzaneh et al (2010) introduced a rigorous bearing capacity analysis based on the upper bound state theorem, using a log-spiral surface algorithm. This paper presents a thorough evaluation of this collapse mechanism and subsequently, a modified failure mechanism is introduced. The collapse mechanism consists of rigid blocks under combined rotational and transitional movements. The effects of the loading parameters on bearing capacity results are then discussed. The findings of this study are compared with the original limit state mechanism as well as previously published solutions, emphasising the accuracy and efficiency of the modified mechanisms. Furthermore, parametric studies are carried out to evaluate the ultimate bearing capacity of shallow foundations resting on a restricted soil, layer using the proposed mechanism. Design tables are finally presented for practical use in geotechnical engineering.

scholarly journals Development of improved models for pile load bearing capacity, settlement and reliability analysis

Vestnik MGSU ◽  
2020 ◽  
pp. 789-823
Author(s):  
Vladimir S. Utkin ◽  
Sergey A. Solovyev
Keyword(s):  
Bearing Capacity ◽  
Operating Conditions ◽  
Performance Criteria ◽  
Pile Foundations ◽  
Load Bearing Capacity ◽  
Foundation Soil ◽  
Important Indicator ◽  
Reliable Determination ◽  
Load Bearing ◽  
Pile Settlement

Introduction. Safety of operation and durability of pile foundations and structures as a whole depend on the values of load bearing capacity of piles and reliability in the foundation soils. The key problem of pile analysis consists in reliable determination of its load bearing capacity values according to all performance criteria of the first and second groups of limit states, in revealing of reliable values of reliability (operation safety), economic efficiency and profitability. Materials and methods. One of the difficulties in detecting the value of the load bearing capacity of friction piles is to determine the values of friction and cohesive forces and their distribution over the side surface of the pile in the foundation soil when the loaded pile is immobilized (at rest). Results. Absence of reliable information on actual friction and cohesive force and, consequently, on actual load bearing capacity of a pile in the conditions of immobility does not allow to estimate its quality taking into account assurance of trouble-free operation (reliability) in real operating conditions at the pre-set operating load, it is impossible to predict the durability of a pile, to make a reasonable choice of pile shape and dimensions, etc. Another pile analysis problem is determining the value of pile settlement. The value of pile settlement is in some cases the most important indicator of the facility performance. Conclusions. New approaches to the operation of piles in the foundation soil on the basis of modern methods of reliability calculations with limited statistical information about controlled parameters are proposed. Improvement and development of pile calculation methods can be found in the calculation of deep trencher foundations, in the calculation of open caissons and caissons, the development of new statutory documents on pile foundations; as well as during training process of various universities and as a source for advanced training of specialists.

scholarly journals THE RELIABILITY ANALYSIS OF EXISTING REINFORCED CONCRETE PILES IN PERMAFROST REGIONS

2017 ◽  
Vol 13 (2) ◽  
pp. 64-72 ◽  
Author(s):  
Vladimir S. Utkin ◽  
Leonid A. Sushev
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Reliability Analysis ◽  
Contact Zone ◽  
Limit State ◽  
Frozen Soil ◽  
Negative Consequences ◽  
Concrete Piles ◽  
Reinforced Concrete Piles ◽  
Permafrost Regions

The article describes the general problem of safe operation of buildings and structures with the dynamics of permafrost in Russia and other countries. The global warming on Earth will lead to global disasters such as failures of buildings and structures. The main reason of these failures will be a reduction of bearing capacity and the reliability of foundations. It is necessary to organize the observations (monitoring) for the process of reducing the bearing capacity of foundations to prevent such accidents and reduce negative consequences, to development of preventive measures and operational methods for the piles reliability analysis. The main load-bearing elements of the foundation are reinforced concrete piles and frozen ground. Reinforced concrete piles have a tendency to decrease the bearing capacity and reliability of the upper (aerial) part and the part in the soil. The article discusses the problem of reliability analysis of existing reinforced concrete piles in upper part in permafrost regions by the reason of pile degradation in the contact zone of seasonal thawing and freezing soil. The evaluation of the probability of failure is important in itself, but also it important for the reliability of foundation: consisting of piles and frozen soil. Authors offers the methods for reliability analysis of upper part of reinforced concrete piles in the contact zone with seasonally thawed soil under different number of random variables (fuzzy variables) in the design mathematical model of a limit state by the strength criterion.

Reliability Method and its Standard of the Composite Foundation Bearing Capacity

2012 ◽  
Vol 170-173 ◽  
pp. 144-147
Author(s):  
Xiao Yun Peng ◽  
Peng Ju Cui
Keyword(s):  
Bearing Capacity ◽  
Reliability Analysis ◽  
Reliability Index ◽  
Limit State ◽  
State Equation ◽  
Composite Foundation ◽  
Analysis Method ◽  
Cement Injection ◽  
Reliability Method ◽  
General Reliability

The general reliability analysis method of composite foundation bearing capacity was established with the example of cement injection pile, its limit state equation and the optimize method was presented, and the standard of reliability index was also proposed according to the corresponding demand of architectural structure. It indicate that the method is reasonable, convenient to calculation and can be popularized in the whole geotechnical engineering.

scholarly journals The influence of the stratum structure of the pipe pile sliding pile of the offshore platform

2021 ◽  
pp. 6
Author(s):  
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
Soft Soil ◽  
Limit State ◽  
Soil Layer ◽  
Measurement Data ◽  
Friction Resistance ◽  
Side Friction ◽  
The Impact ◽  
Bearing Layer

This article has carried on the theoretical analysis to the generation mechanism of the sliding pile phenomenon. A certain prediction was made on the causes of slipping piles and their influencing factors. At the same time, it is based on the collected field measurement data, an engineering example is selected to briefly analyze the changes in the bearing capacity of the pile foundation after the sliding pile occurs. It is found that the influence of the sliding pile on the bearing capacity of the pile foundation is mainly the influence on the side friction resistance of the pile, and the reduction of the soil resistance is also mainly due to the reduction of the side friction resistance of the pile. Finally, using ABAQUS finite element analysis software, a numerical simulation analysis was carried out on the changes of the stratum structure, the analysis results show that the position change of the soft soil layer has a certain influence on the bearing capacity of the pile, but it does not change the settlement of the pile top under the limit state; The greater the strength of the supporting layer, the greater the bearing capacity and the greater the displacement when reaching the limit state; The length of the slipped pile does not affect the bearing capacity of the pile foundation, and the farther the slipping occurs from the bearing layer, the smaller the impact on the bearing capacity of the pile foundation. Therefore, in the actual project, attention should be paid to the selection of the bearing layer and the soft soil layer close to the bearing layer should be removed to reduce the impact of the slipping pile on the bearing capacity of the pile foundation and ensure that the bearing capacity of the pile foundation meets the design requirements.

scholarly journals Seismic bearing capacity with variable shear transfer

1995 ◽  
Vol 28 (2) ◽  
pp. 153-163 ◽  
Author(s):  
X. Shi ◽  
R. Richards
Keyword(s):  
Bearing Capacity ◽  
Limit State ◽  
Design Procedure ◽  
Shear Stresses ◽  
Earthquake Intensity ◽  
Design Factor ◽  
Foundation Soil ◽  
Shear Transfer ◽  
Seismic Bearing Capacity ◽  
Reserve Strength

The seismic degradation of bearing capacity for drained soils is shown to depend primarily on two factors related to earthquake acceleration: (a) the lateral inertial forces in the structure transmitted as shear at the foundation-soil interface and (b) the lateral body forces in the soil itself. Both induce shear stresses using up the reserve strength of the soil to carry the footing load. During those short periods when this reserve strength provided by the static design factor of safety is exhausted, the footing settles and moves laterally. Solutions for this seismic limit state defining the critical acceleration at which it occurs are determined for any value of shear transfer first by the "exact" method of characteristics and then by a simple Coulomb-type approximate mechanism. Expressions for seismic bearing capacity factors that are directly related to their static counterparts are nearly identical by either method. Thus a straightforward sliding block procedure based on the Coulomb mechanism with examples is presented for computing accumulating settlements due to the periodic loss of bearing capacity. Conversely, this approach leads to a modified static design procedure for shallow footings to limit seismic settlements in a prescribed earthquake intensity zone.

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