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.

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.

Influence of Human Error on Structural Reliability

2017 ◽  
Author(s):  
Eric Brehm ◽  
Robert Hertle ◽  
Markus Wetzel
Keyword(s):  
Human Error ◽  
Structural Reliability ◽  
Failure Modes ◽  
Structural Model ◽  
Limit State ◽  
Design Procedure ◽  
Material Strength ◽  
Limit States ◽  
The Impact

In common structural design, random variables, such as material strength or loads, are represented by fixed numbers defined in design codes. This is also referred to as deterministic design. Addressing the random character of these variables directly, the probabilistic design procedure allows the determination of the probability of exceeding a defined limit state. This probability is referred to as failure probability. From there, the structural reliability, representing the survival probability, can be determined. Structural reliability thus is a property of a structure or structural member, depending on the relevant limit states, failure modes and basic variables. This is the basis for the determination of partial safety factors which are, for sake of a simpler design, applied within deterministic design procedures. In addition to the basic variables in terms of material and loads, further basic variables representing the structural model have to be considered. These depend strongly on the experience of the design engineer and the level of detailing of the model. However, in the clear majority of cases [1] failure does not occur due to unexpectedly high or low values of loads or material strength. The most common reasons for failure are human errors in design and execution. This paper will provide practical examples of original designs affected by human error and will assess the impact on structural reliability.

Reliability analysis of wood I-joists

1993 ◽  
Vol 20 (4) ◽  
pp. 564-573 ◽  
Author(s):  
R. O. Foschi ◽  
F. Z. Yao
Keyword(s):  
Reliability Analysis ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Limit State ◽  
Load Carrying Capacity ◽  
Limit States ◽  
Element Analysis ◽  
Strength Limit ◽  
Reliability Method ◽  
Load Carrying

This paper presents a reliability analysis of wood I-joists for both strength and serviceability limit states. Results are obtained from a finite element analysis coupled with a first-order reliability method. For the strength limit state of load-carrying capacity, multiple failure modes are considered, each involving the interaction of several random variables. Good agreement is achieved between the test results and the theoretical prediction of variability in load-carrying capacity. Finally, a procedure is given to obtain load-sharing adjustment factors applicable to repetitive member systems such as floors and flat roofs. Key words: reliability, limit state design, wood composites, I-joist, structural analysis.

scholarly journals Reliability Analysis of Anchored Geotechnical Structures for the Design Limit States

2020 ◽  
Vol 8 (2) ◽  
pp. 35-47
Author(s):  
Sohaib K Al-Mamoori ◽  
Laheab A. Al-Maliki ◽  
Khaled El-Tawel
Keyword(s):  
Reliability Analysis ◽  
Reliability Index ◽  
Failure Modes ◽  
Limit State ◽  
Tensile Failure ◽  
Limit States ◽  
Geotechnical Parameters ◽  
Retaining Structure ◽  
Geotechnical Structures ◽  
Bending Failure

Reliability has been considered of magnificent importance in engineering design specially in geotechnical engineering due to the unpredictable conditions of soil layers. It is essential to establish well- designed failure modes that could guarantee safety and durability of the proposed structure. This study aims to suggest a reliability analyses procedure for retaining walls by the mean of a reliability index β using the specifications of AASHTO Bridge Design 2002, Eurocode 7, and DIN EN 1993-5 norms. Two failure modes; Tensile failure of tendon (G1) and Failure by bending (G2) were studied and compared by using equation of the Design Limit State (DLS) and by taking some basic geotechnical parameters as Random Variables RV. The analyses demonstrated that the reliability index β and probability of failure Pf are the most important parameter in the reliability analysis. Also, the suitable height (H) for the retaining structure (for all angles ϴ) equals to 6 m and the most critical angle is ϴ= 45º to prevent the failure by tensile of tendon. While the bending failure reliability analysis shows that all heights of retaining structure are suitable. After comparing the two cases it was found that (G1) is more dangerous than (G2).

scholarly journals Stability of crane beam walls with fatigue cracksin the compressed belt zone

2020 ◽  
Vol 17 (4) ◽  
pp. 47-53
Author(s):  
A. E. Kubasevich ◽  
Keyword(s):  
Crack Length ◽  
Bearing Capacity ◽  
Critical Stress ◽  
Fatigue Cracks ◽  
Limit State ◽  
Bending Moment ◽  
Limit States ◽  
Stress Strain ◽  
Beam Bending ◽  
Stress Parameters

The paper describes a method for assessing the bearing capacity of the crane beam walls with fatigue cracks. There has been developed and implemented an algorithm for evaluating the stress-strain and limit state of the beam with a crack in the wall under a compressed belt. There has been established the dependence of the stress-strain and limit states of the beam wall on the value of the initial relative beam bending and the crack length in the section under the action of the bending moment and transverse force. The author presents the results of numerical studies of the effect of cracks on the bearing capacity of the beam wall. The influence of the amplitude of the initial beam wall deflection on the critical stress parameters is revealed. The dependence of the values of critical stress parameters on the relative crack length is considered.

scholarly journals Research on Intelligent Evaluation System of Load-bearing Capacity of Existing Reinforced Concrete Bridge

2020 ◽  
Vol 165 ◽  
pp. 04056
Author(s):  
An Zhao ◽  
Qiang Xu ◽  
Jianyong Song
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Evaluation System ◽  
Limit State ◽  
Concrete Bridge ◽  
Parametric Modelling ◽  
Limit States ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Reinforced Concrete Bridge

The intelligent evaluation system of existing reinforced concrete bridge “BLP” is a special software for the load-bearing capacity rapid analysis and evaluation of the existing reinforced concrete bridge, which was developed by the Highway Research Institute of the Ministry of Transport. Based on the parametric modelling method, it can quickly and easily establish the finite element plane model of the bridge structure for the static analysis of ultimate bearing capacity limit states and serviceability limit state, under variety norms. And it can easily and quickly build variable-section beams and rebars, with the special module. According to the comprehensive modification method of the load-bearing capacity evaluation, it can automatically recommend checking sections, and automatically calculate partial modification coefficient of resistance effect, and conveniently judge the safety coefficient of the sections, and quickly get the results of bridge load-bearing capacity. In summary, this system can significantly improve the work efficiency and accuracy of load-bearing capacity for exiting reinforced concrete bridge. This paper introduces in detail the characteristics of the intelligent analysis technology, calculation principle and real bridge application examples of the system.

Demonstration of a New, Fast Probability Integration Method for Reliability Analysis

1987 ◽  
Vol 109 (1) ◽  
pp. 24-28 ◽  
Author(s):  
Yih-Tsuen Wu
Keyword(s):  
Reliability Analysis ◽  
Integration Method ◽  
Limit State ◽  
Probability Of Failure ◽  
New Method ◽  
Limit States ◽  
Linear And Nonlinear ◽  
Accurate Probability

The performance of a new, fast probability integration method which combines an improved equivalent normal concept and a scheme for linearizing a quadratic limit state is carefully examined. The examples tested include various combinations of linear and nonlinear limit states with normal and non-normal variables; some examples are considered the worst possible cases. It is demonstrated that the new method is able to provide accurate probability-of-failure estimates for most cases and performs reasonably well when the Rackwitz-Fiessler method produces severe errors.

scholarly journals Structural Reliability Analysis of Ship Hulls Accounting for Collision or Grounding Damage

2020 ◽  
Author(s):  
Branka Bužančić Primorac ◽  
Joško Parunov ◽  
C. Guedes Soares
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Limit State ◽  
Random Variables ◽  
Bending Moment ◽  
State Equation ◽  
Limit States ◽  
Moment Capacity ◽  
Ship Hulls ◽  
Structural Reliability Analysis

AbstractClassical structural reliability analysis of intact ship hulls is extended to the case of ships with collision or grounding damages. Still water load distribution and residual bending moment capacity are included as random variables in the limit state equation. The probability density functions of these random variables are defined based on random damage parameters given by the Marine Environment Protection Committee of the International Maritime Organization, while the proposed reliability formulation is consistent with international recommendations and thus may be valuable in the development of rules for accidental limit states. The methodology is applied on an example of an Aframax oil tanker. The proposed approach captures in a rational way complex interaction of different pertinent variables influencing safety of damaged ship structure.

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