Integrating Eurocode 7 (load and resistance factor design) using nonconventional factoring strategies in slope stability analysis

2014 ◽  
Vol 51 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Lysandros Pantelidis ◽  
D.V. Griffiths
Keyword(s):  
Shear Strength ◽  
Limit State ◽  
Design Standards ◽  
Safety Level ◽  
Eurocode 7 ◽  
Design Values ◽  
Factor Design ◽  
State Method ◽  
The One ◽  
Load And Resistance Factor

In traditional allowable stress design, as known, the safety factor is calculated with respect to shear strength of soil(s) by dividing the available shear strength by the mobilized stresses. The limit-state method, on the other hand, compares — in the form of the inequality Ed ≤ Rd — the effects of all the actions, Ed, with the corresponding resistance of the ground, Rd. Although this method considers different loading conditions by using suitable combinations of design values, it is still based on direct comparison of the available shear strength with the mobilized stresses. In the present paper, various factoring strategies (in addition to the traditional one with respect to shear strength of soils) are integrated into a limit-state method framework. Eurocode 7 has been chosen for this purpose. The whole procedure aims at giving a more comprehensive insight into the design of slopes and the sensitivity of safety level of slopes to the various parameters. In addition, the proposed methodology, as shown, may result in a safety level of slopes significantly lower than the respective one obtained using the limit-state method in its traditional form. As man-made slopes that conform to design standards often fail in practice, even though conservative input values are used, these failures must be treated with more skepticism by practitioners adopting supplementary design practices such the one presented herein.

Reliability-Based LRFD Criteria for Unstiffened Panel of Ship Structures

2013 ◽  
Author(s):  
Yong Bai ◽  
Miao-hua Qian
Keyword(s):  
Limit State ◽  
State Equation ◽  
Safety Factors ◽  
Ship Structures ◽  
Future Design ◽  
Practical Project ◽  
Safety And Reliability ◽  
Partial Safety Factors ◽  
Factor Design ◽  
Load And Resistance Factor

It is of significance to do the research of safety and reliability for ship structures, especially for marine structures because of the poor conditions and high risks, future design for ship structures will move toward a more rational and probability-based design. This paper chooses the unstiffened panel of ship structures as the research subject. Based on the MATLAB software, this paper develops the procedures and calculates one limit state equation of the panel, derives partial safety factors (PSF) for the Load and Resistance Factor Design (LRFD) of the panel under different reliability index levels. The PSF may provide a reference for the practical project design.

On the Assessment of the Seismic Vulnerability of Ancient Churches

2015 ◽  
pp. 794-830 ◽  
Author(s):  
Pardo Antonio Mezzapelle ◽  
Stefano Lenci
Keyword(s):  
Structural Changes ◽  
Seismic Vulnerability ◽  
Risk Index ◽  
Limit State ◽  
Ultimate Limit State ◽  
Masonry Building ◽  
Safety Level ◽  
Future Situation ◽  
Equivalent Frame ◽  
The One

The chapter deals with the assessment of the seismic vulnerability of the “San Francesco ad Alto” historical masonry building, a former church located in Ancona (Italy), which is currently used as a Regional Headquarter of the Marche Region by the Italian Army. The interest toward this building comes from a double motivation. From the one side, it underwent a series of structural changes, including the addition of a new floor splitting in two levels the original nave, which makes the structure very peculiar and closer to a classical building than to a church. From the other side, it is no longer used as a church, a fact that changes the hazard aspects. The construction schematically consists of two masonry boxes overlapping, the lower being wider than the upper. It has various characteristic structural elements, such as some semicircular arches, segmental arches, timber floors, a barrel vault, some wooden trusses on the roof and steel ties in retention of the facade and of the external walls. The equivalent frame method is used, and several pushover analyses are performed. The seismic action has been defined considering the building both with strategic (current situation) and with ordinary (possible future situation) importance during earthquakes. The role of the masonry spandrels on the response of the structure has been investigated in depth and the main effects highlighted. The result of the pushover analyses is a seismic risk index (IR), that defines the safety level of the construction with respect to one ultimate limit state (SLU), in particular the so-called limit state of “saving life” (SLV).

Calibration concepts for load and resistance factor design (LRFD) of reinforced soil walls

2008 ◽  
Vol 45 (10) ◽  
pp. 1377-1392 ◽  
Author(s):  
Richard J. Bathurst ◽  
Tony M. Allen ◽  
Andrzej S. Nowak
Keyword(s):  
Limit State ◽  
Reinforced Soil ◽  
Resistance Factor ◽  
Resistance Factors ◽  
Soil Walls ◽  
Calibration Methods ◽  
Load And Resistance Factors ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Reinforced Soil Walls

Reliability-based design concepts and their application to load and resistance factor design (LRFD or limit states design (LSD) in Canada) are well known, and their adoption in geotechnical engineering design is now recommended for many soil–structure interaction problems. Two important challenges for acceptance of LRFD for the design of reinforced soil walls are (i) a proper understanding of the calibration methods used to arrive at load and resistance factors, and (ii) the proper interpretation of the data required to carry out this process. This paper presents LRFD calibration principles and traces the steps required to arrive at load and resistance factors using closed-form solutions for one typical limit state, namely pullout of steel reinforcement elements in the anchorage zone of a reinforced soil wall. A unique feature of this paper is that measured load and resistance values from a database of case histories are used to develop the statistical parameters in the examples. The paper also addresses issues related to the influence of outliers in the datasets and possible dependencies between variables that can have an important influence on the results of calibration.

Reliability Based Design Criteria for Installation of Pipelines in the Bay of Campeche, Mexico: Part 2

2002 ◽  
Author(s):  
Robert Bea ◽  
Tao Xu ◽  
Ernesto Heredia-Zavoni ◽  
Leonel Lara ◽  
Rommel Burbano
Keyword(s):  
Limit State ◽  
Companion Paper ◽  
Design Criteria ◽  
Ultimate Limit State ◽  
Large Database ◽  
Reliability Based Design ◽  
Working Stress ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Ultimate Limit

Studies have been performed to propose reliability based design criteria for the installation of pipelines in the Bay of Campeche, Mexico. This paper summarizes formulations that were used to characterize the important Ultimate Limit State capacities of the pipelines during the installation period (collapse, bending, tension, combined, and propagating buckling). A large database of laboratory and numerical analysis ‘tests’ (more than 2,000 results) to determine pipeline capacities was assembled to help evaluate the Biases (ratio of measured/predicted capacities) in the analytical methods used to determine pipeline capacities. Given the formulations, target reliabilities, and installation demand characterizations summarized in a companion paper (Part 1), installation design criteria were developed for both Working Stress Design and Load and Resistance Factor Design formats.

Reliability Based Design Criteria for Installation of Pipelines in the Bay of Campeche, Mexico: Part 1

2002 ◽  
Author(s):  
Robert Bea ◽  
Tao Xu ◽  
Ernesto Heredia-Zavoni ◽  
Leonel Lara ◽  
Rommel Burbano
Keyword(s):  
Limit State ◽  
Companion Paper ◽  
Design Guidelines ◽  
Design Criteria ◽  
Ultimate Limit State ◽  
Reliability Based Design ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Ultimate Limit ◽  
Allowable Stress Design

Studies have been performed to propose reliability based design criteria for the installation of pipelines in the Bay of Campeche, Mexico. This paper summarizes the reliability formulations that were used to develop Allowable Stress Design and Load and Resistance Factor Design guidelines for Ultimate Limit State conditions, background on the target reliabilities that were used in the development, and the methods that were used to characterize the demands (loads, displacements) induced in pipelines during their installation. This paper summarizes data that was gathered during the installation of pipelines in the Bay of Campeche to help define the Biases (actual stresses/calculated stresses) associated with the analytical model used to predict installation demands. These results are compared with those published previously based on other field and laboratory tests. A companion paper details the analyses of pipeline Ultimate Limit State capacities and the Biases associated with these capacities.

Comparative Analysis on the Allowable Stress and Limit State Methods of Crane Structure Design Standards at Home and Abroad

2012 ◽  
Vol 468-471 ◽  
pp. 559-564 ◽  
Author(s):  
Yuan Yuan Teng ◽  
Da Shan Dong ◽  
Hui Qing Qiu
Keyword(s):  
Comparative Analysis ◽  
Limit State ◽  
Reference Value ◽  
Metal Structure ◽  
Structure Design ◽  
Design Parameters ◽  
Allowable Stress ◽  
Design Standards ◽  
State Method ◽  
At Home

This paper adopts the allowable stress and limit state methods of Chinese and European crane structure design standards(GB3811-2008 and FEM-1998 ), and illustrates correspondingly in detail the computing means on the overall checking of strength, static and dynamics stiffness, buckling of bar and plate, and fatigue. Taking a real crane as an example, according to the above three specifications, it designs the crane’s metal structure again, checks all aspects and guarantees the strength, buckling and fatigue indexes all reach 90 percent of the permissions, then comparative analyzes the new design parameters and checking indicators, combining failure probability obtained by PDS. It provides helpful and reference value for understanding the transition from the allowable stress to limit state method in design standards and the differences of theirs’ at home and abroad.

Load and resistance factor design of shallow foundations against bearing failure

2008 ◽  
Vol 45 (11) ◽  
pp. 1556-1571 ◽  
Author(s):  
Gordon A. Fenton ◽  
D. V. Griffiths ◽  
Xianyue Zhang
Keyword(s):  
Bearing Capacity ◽  
Limit State ◽  
Resistance Factor ◽  
Shallow Foundation ◽  
Ultimate Limit State ◽  
Full Potential ◽  
Design Codes ◽  
Reliability Based Design ◽  
Factor Design ◽  
Load And Resistance Factor

Shallow foundation designs are typically governed either by settlement, a serviceability limit state, or by bearing capacity, an ultimate limit state. While geotechnical engineers have been designing against these limit states for over half a century, it is only recently that they have begun to migrate towards reliability-based designs. At the moment, reliability-based design codes are generally derived through calibration with traditional working stress designs. To take advantage of the full potential of reliability-based design the profession must go beyond calibration and take geotechnical uncertainties into account in a rational fashion. This paper proposes a load and resistance factor design (LRFD) approach for the bearing capacity design of a strip footing, using load factors as specified by structural codes. The resistance factors required to achieve an acceptable failure probability are estimated as a function of the spatial variability of the soil and by the level of “understanding” of the soil properties in the vicinity of the foundation. The analytical results, validated by simulation, are primarily intended to aid in the development of the next generation of reliability-based geotechnical design codes, but can also be used to assess the reliability of current designs.

Sign in / Sign up

Export Citation Format

Share Document