scholarly journals On Some Methods in Safety Evaluation in Geotechnics

2015 ◽  
Vol 37 (2) ◽  
pp. 17-32 ◽  
Author(s):  
Wojciech Puła ◽  
Łukasz Zaskórski
Keyword(s):  
Design Method ◽  
Safety Evaluation ◽  
Short Review ◽  
Cohesionless Soils ◽  
Reliability Based Design ◽  
Working Stress ◽  
Rigid Pile ◽  
Complementary Role ◽  
Capacity Calculation ◽  
Reliability Methods

Abstract The paper demonstrates how the reliability methods can be utilised in order to evaluate safety in geotechnics. Special attention is paid to the so-called reliability based design that can play a useful and complementary role to Eurocode 7. In the first part, a brief review of first- and second-order reliability methods is given. Next, two examples of reliability-based design are demonstrated. The first one is focussed on bearing capacity calculation and is dedicated to comparison with EC7 requirements. The second one analyses a rigid pile subjected to lateral load and is oriented towards working stress design method. In the second part, applications of random field to safety evaluations in geotechnics are addressed. After a short review of the theory a Random Finite Element algorithm to reliability based design of shallow strip foundation is given. Finally, two illustrative examples for cohesive and cohesionless soils are demonstrated.

A Safety Factor Method for Reliability-Based Component Design

2021 ◽  
pp. 1-34
Author(s):  
Jianhua Yin ◽  
Xiaoping Du
Keyword(s):  
Safety Factor ◽  
Design Method ◽  
Deterministic Component ◽  
Reliability Based Design ◽  
Component Design ◽  
Design Variables ◽  
Wide Range ◽  
Reliability Method ◽  
Reliability Methods ◽  
Input Variables

Abstract Reliability-based design (RBD) identifies design variables that maintain reliability at a required level. For many routine component design jobs, RBD may not be practical as it requires nonlinear optimization and specific reliability methods, especially for those design jobs which are performed manually or with a spreadsheet. This work develops a practical approach to reliability-based component design so that the reliability target can be achieved by conducting traditional component design repeatedly using a deterministic safety factor. The new component design is based on the First Order Reliability Method, which iteratively assigns the safety factor during the design process until the reliability requirement is satisfied. In addition to several iterations of deterministic component design, the other additional work is the calculation of the derivatives of the design margin with respect to the random input variables. The proposed method can be used for a wide range of component design applications. For example, if a deterministic component design is performed manually or with a spreadsheet, so is the reliability-based component design. Three examples are used to demonstrate the practicality of the new design method.

A Practical Safety Factor Method for Reliability-Based Component Design

2020 ◽  
Author(s):  
Jianhua Yin ◽  
Xiaoping Du
Keyword(s):  
Safety Factor ◽  
Design Method ◽  
Deterministic Component ◽  
Reliability Based Design ◽  
Component Design ◽  
Design Variables ◽  
Wide Range ◽  
Reliability Method ◽  
Reliability Methods ◽  
Input Variables

Abstract Reliability-based design (RBD) identifies design variables that maintain reliability at a required level. For many routine component design jobs, RBD may not be practical as it requires nonlinear optimization and specific reliability methods, especially for those design jobs which are performed manually or with a spreadsheet. This work develops a practical approach to reliability-based component design so that the reliability target can be achieved by conducting traditional component design repeatedly using a deterministic safety factor. The new component design is based on the First Order Reliability Method, which iteratively assigns the safety factor during the design process until the reliability requirement is satisfied. In addition to a number of iterations of deterministic component design, the other additional work is the calculation of the derivatives of the design margin with respect to the random input variables. The proposed method can be used for a wide range of component design applications. For example, if a deterministic component design is performed manually or with a spreadsheet, so it the reliability-based component design. Three examples are used to demonstrate the practicality of the new design method.

Research Situation on the Performance-Based Seismic Design Method for Reinforced Concrete Structure

2010 ◽  
Vol 163-167 ◽  
pp. 1757-1761
Author(s):  
Yong Le Qi ◽  
Xiao Lei Han ◽  
Xue Ping Peng ◽  
Yu Zhou ◽  
Sheng Yi Lin
Keyword(s):  
Reinforced Concrete ◽  
Seismic Design ◽  
Design Method ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Seismic Evaluation ◽  
Seismic Codes ◽  
Performance Based Seismic Design ◽  
Capacity Calculation ◽  
Seismic Design Method

Various analytical approaches to performance-based seismic design are in development. Based on the current Chinese seismic codes，elastic capacity calculation under frequent earthquake and ductile details of seismic design shall be performed for whether seismic design of new buildings or seismic evaluation of existing buildings to satisfy the seismic fortification criterion “no damage under frequent earthquake, repairable under fortification earthquake, no collapse under severe earthquake”. However, for some special buildings which dissatisfy with the requirements of current building codes, elastic capacity calculation under frequent earthquake is obviously not enough. In this paper, the advanced performance-based seismic theory is introduced to solve the problems of seismic evaluation and strengthening for existing reinforced concrete structures, in which story drift ratio and deformation of components are used as performance targets. By combining the features of Chinese seismic codes, a set of performance-based seismic design method is established for reinforced concrete structures. Different calculation methods relevant to different seismic fortification criterions are adopted in the proposed method, which solve the problems of seismic evaluation for reinforced concrete structures.

Strength Model Uncertainties of Burst, Yielding, and Excessive Bending of Piping

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Kleio Avrithi ◽  
Bilal M. Ayyub
Keyword(s):  
Structural Design ◽  
Design Method ◽  
Strength Model ◽  
Allowable Stress ◽  
Model Uncertainties ◽  
Reliability Based Design ◽  
Design Variables ◽  
Strength Models ◽  
Potential Use ◽  
Allowable Stress Design

Nuclear safety-piping is designed according to the ASME Boiler and Pressure Vessel Code, Sections III, NB-, NC-, and ND-3600 that use the allowable stress design method (ASD). The potential use instead of reliability-based design equations for nuclear piping could benefit the structural design by providing, among others, consistent reliability levels for piping. For the development of such equations, not only the probabilistic characteristics of the design variables are needed, but also the quantification of the uncertainties introduced by the strength models that are used in order to estimate the resistance of pipes subjected to different loadings. This paper evaluates strength models, and therefore provides necessary information for the reliability-based design of pipes for burst or yielding due to internal pressure and for excessive bending.

scholarly journals Proposal of a Reliability-Based Design Method for Static and Fatigue Strength of MEMS Micromirror

2006 ◽  
Vol 55 (3) ◽  
pp. 290-294 ◽  
Author(s):  
Satoshi IZUMI ◽  
Masayuki KADOWAKI ◽  
Shinsuke SAKAI ◽  
Yuzuru UEDA ◽  
Atsushi SUZUKI
Keyword(s):  
Fatigue Strength ◽  
Design Method ◽  
Reliability Based Design

Application of High-Grade Steels to Onshore Natural Gas Pipelines Using Reliability-Based Design Method

2006 ◽  
Author(s):  
Joe Zhou ◽  
Brian Rothwell ◽  
Wenxing Zhou ◽  
Maher Nessim
Keyword(s):  
High Pressure ◽  
Wall Thickness ◽  
Design Method ◽  
Large Diameter ◽  
Economic Assessment ◽  
High Grade ◽  
Gas Pipelines ◽  
Natural Gas Pipelines ◽  
Reliability Based Design ◽  
Design Factors

Two example onshore gas pipelines were designed using a reliability-based approach. The first example (1219 mm, 17.2 MPa) represents a high-pressure large-diameter pipeline; the second example has a smaller diameter (762 mm) and lower pressure (9.9 MPa). Three steel grades (X70, X80 and X100) were used to develop three design solutions for each example. The wall thickness-related life cycle costs of the designs were evaluated. The design outcomes show that the reliability targets for both examples can be met using X100 steels and high equivalent design factors (0.93 for the first example and 0.9 for the second example). Moreover, ruptures and excessive plastic deformation of a defect free pipe were found to be insignificant integrity threats even when the design uses X100 and relatively high equivalent design factors such as 0.85 and 0.9. The economic assessment results show that the X100 design is the most economical option for the high-pressure large-diameter example. However, using X100 does not show a clear economic advantage over using X80 for the second example mainly because the wall thickness for the design using X100 is governed by the maximum D/t ratio constraint. The study also demonstrates the advantages of the reliability-based approach as a valuable tool in assessing the feasibility and potential benefits of using high-grade steels on a pipeline project.

Reliability-Based Design of Externally Pressurized Vessels

1998 ◽  
Vol 120 (3) ◽  
pp. 149-153 ◽  
Author(s):  
A. C. Morandi ◽  
P. K. Das ◽  
D. Faulkner
Keyword(s):  
Safety Factor ◽  
Design Procedure ◽  
External Pressure ◽  
Reliability Based Design ◽  
Safety Margins ◽  
Sensitivity Studies ◽  
Pressure Maximum ◽  
Reliability Methods ◽  
Level I ◽  
Future Work

A reliability-based Level I design procedure is proposed for ring-stiffened cylindrical shells under external pressure. The main collapse modes and the present safety factor approach are reviewed. The major aspects involved in code development, such as the statistical properties of the basic variables, reliability methods, sensitivity studies, code format, target reliability, partial safety factor optimization, and comparison with the present practice are described. Safety margins for design are proposed which depend on the design pressure, maximum expected overdive, and shell slenderness. Some suggestions for future work are also given.

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