Canadian Standards Association standard A23.3-04 resistance factor for concrete in compression

2007 ◽  
Vol 34 (9) ◽  
pp. 1029-1037 ◽  
Author(s):  
F M Bartlett
Keyword(s):  
Precast Concrete ◽  
Limit State ◽  
Compressive Force ◽  
Bending Moment ◽  
Resistance Factor ◽  
Ultimate Limit State ◽  
Reliability Indices ◽  
Interaction Diagram ◽  
Code Calibration ◽  
Stress Block

This paper presents the rationale for increasing the resistance factor for concrete in compression in the 2004 edition of the Canadian Standards Association (CSA) standard A23.3, Design of concrete structures, from 0.60 to 0.65 and for precast concrete produced in CSA-certified plants from 0.65 to 0.70. The new values are supported by a probability-based resistance factor calibration and an investigation of their impact in the context of current American standards and past editions of A23.3. The work was initiated because parameters for the rectangular concrete stress block introduced in the 1994 edition of A23.3 give smaller factored resistances for concretes with strengths between 20 and 40 MPa. Minimum target reliability indices for components that fail suddenly are maintained using the new resistance factors. In the regions of compressive force – bending moment interaction diagrams that are controlled by the resistance factor for concrete, the factored resistances computed using the 2004 edition of A23.3 are similar to those of current American design criteria.Key words: code calibration, compression-initiated failure, concrete, interaction diagram, rectangular stress block, ultimate limit state.

Combined flexure and torsion of I-shaped steel beams

1989 ◽  
Vol 16 (2) ◽  
pp. 124-139 ◽  
Author(s):  
Robert G. Driver ◽  
D. J. Laurie Kennedy
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Phase Behaviour ◽  
Inelastic Interaction ◽  
Steel Beams ◽  
Ultimate Limit State ◽  
Second Phase ◽  
Design Standards ◽  
Limit States ◽  
Interaction Diagram

Design standards provide little information for the design of I-shaped steel beams not loaded through the shear centre and therefore subjected to combined flexure and torsion. In particular, methods for determining the ultimate capacity, as is required in limit states design standards, are not presented. The literature on elastic analysis is extensive, but only limited experimental and analytical work has been conducted in the inelastic region. No comprehensive design procedures, applicable to limit states design standards, have been developed.From four tests conducted on cantilever beams, with varying moment–torque ratios, it is established that the torsional behaviour has two distinct phases, with the second dominated by second-order geometric effects. This second phase is nonutilizable because the added torsional restraint developed is path dependent and, if deflections had been restricted, would not have been significant. Based on the first-phase behaviour, a normal and shearing stress distribution on the cross section is proposed. From this, a moment–torque ultimate strength interaction diagram is developed, applicable to a number of different end and loading conditions. This ultimate limit state interaction diagram and serviceability limit states, based on first yield and on distortion limitations, provide a comprehensive design approach for these members. Key words: beams, bending moment, flexure, inelastic, interaction diagram, I-shaped, limit states, serviceability, steel, torsion, torque, ultimate.

EXPERIMENTAL EVALUATION OF FLEXURAL CAPACITY OF FULL SCALE PRECAST CONCRETE SHEETPILE

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Geem Eng Tan ◽  
Tai Boon Ong ◽  
Kok Keong Choong ◽  
Chong Yong Ong
Keyword(s):  
Precast Concrete ◽  
Limit State ◽  
Bending Moment ◽  
Test Method ◽  
Ultimate Limit State ◽  
Flexural Capacity ◽  
Test Procedures ◽  
Ground Conditions ◽  
Nursing College ◽  
Set Up

A flexural capacity test is presented of a long precast concrete sheetpile system, intended as a protection wall for a water storage canal bank in soft-ground conditions, for a nursing college in Penang, Malaysia. The precast concrete sheetpile with a length of 7 m and a maximum exposed corrugated-section height of 1.8 m, was designed at Ultimate Limit State (ULS) bending moment of 175 kNm. A total of 2 specimens of precast concrete sheetpiles were tested in the Heavy Structure Laboratory at School of Civil Engineering, Universiti Sains Malaysia. The test method specified in Malaysian Standard MS 1314 was adopted. The results showed that the capacity of Specimens 1 and 2 were respectively 1.49 and 1.48 times higher than the designed capacity at ULS. The test set-up, to reflect the practical behavior of precast concrete sheetpile, and the test procedures are also described.

Anchor rod forces and maximum bending moments in sheet pile walls using the factored strength approach

1996 ◽  
Vol 33 (5) ◽  
pp. 815-821 ◽  
Author(s):  
A B Schriver ◽  
A J Valsangkar
Keyword(s):  
Water Pressure ◽  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Sheet Pile ◽  
Limit States ◽  
Working Stress ◽  
Geotechnical Design ◽  
Ultimate Limit State Design ◽  
Sheet Pile Wall

Recently, the limit states approach using factored strength has been recommended in geotechnical design. Some recent research has indicated that the application of limit states design using recommended load and strength factors leads to conservative designs compared with the conventional methods. In this study the influence of sheet pile wall geometry, type of water pressure distribution, and different methods of analysis on the maximum bending moment and achor rod force are presented. Recommendations are made to make the factored strength design compatible with conventional design. Key words: factored strength, working stress design, ultimate limit state design, anchored sheet pile wall, bending moment, anchor rod force.

Statistical evaluation of model factors in reliability calibration of high-displacement helical piles under axial loading

2020 ◽  
Vol 57 (2) ◽  
pp. 246-262 ◽  
Author(s):  
Chong Tang ◽  
Kok-Kwang Phoon
Keyword(s):  
Limit State ◽  
Axial Loading ◽  
Design Guidelines ◽  
Resistance Factor ◽  
Hyperbolic Model ◽  
Ultimate Limit State ◽  
Dense Sand ◽  
Capacity Model ◽  
Helical Piles ◽  
Two Parameters

An industry survey suggests an increasing application of high-displacement helical piles with greater shaft and helix diameters to support various structures. In this paper, a database of 84 static load tests is compiled and analyzed to evaluate the disturbance effect and characterize the model factors that can be used for reliability-based limit state design. The measured capacity is defined as the load at a pile head settlement equal to 5% of helix diameter. For similar helix configurations tested at the same site, the ratio of uplift to compression capacity indicates a low degree of disturbance for very stiff clay (0.8–1) and a medium degree of disturbance for dense sand (0.6–0.8). At the ultimate limit state, the model factor is defined as the ratio between measured and calculated capacity, where three design guidelines are considered. A hyperbolic model with two parameters is used to fit the load–displacement curves. At the serviceability limit state, the model factor can be defined with the hyperbolic parameters. Based on the database, probabilistic distributions of the capacity model factor and hyperbolic parameters are established. Finally, the capacity model statistics are applied to calculate the resistance factor in the load and resistance factor design.

Evaluation of IACS Common Structural Rules in Terms of Ultimate Limit State Design and Assessment of Ship Structures

2007 ◽  
Author(s):  
Jeom Kee Paik ◽  
Bong Ju Kim ◽  
Jung Kwan Seo
Keyword(s):  
Limit State ◽  
Bending Moment ◽  
Ultimate Limit State ◽  
Stiffened Plate ◽  
Plate Structures ◽  
Hull Girder ◽  
Structural Rules ◽  
Out Of Plane ◽  
Common Structural Rules ◽  
Ultimate Limit

The aim of the present paper is to evaluate the ultimate limit state performance of an AFRAMAX-class hypothetical double hull oil tanker structure designed by IACS CSR (Common Structural Rules) method, compared with the same-class/type tanker structure designed by IACS pre-CSR method. The ultimate strengths of stiffened plate structures in deck and bottom parts under combined in-plane and out-of-plane actions, and hull girder against vertical bending moment, are computed for the two designs, and the resulting computations are compared. ALPS/ULSAP program is used for the ultimate limit state assessment of stiffened plate structures, while ALPS/HULL program is employed for the progressive hull collapse analysis. ANSYS nonlinear FEA method, which uses more refined technology, is also used for the same purpose. The insights and developments obtained from the present study are addressed.

On the Application of Structural Reliability Analysis

2017 ◽  
Author(s):  
Torfinn Hørte ◽  
Gudfinnur Sigurdsson
Keyword(s):  
Reliability Analysis ◽  
Structural Engineering ◽  
Structural Reliability ◽  
Limit State ◽  
Design Analysis ◽  
Ultimate Limit State ◽  
Hull Girder ◽  
Structural Reliability Analysis ◽  
Code Calibration ◽  
Calculated Probability

Structural Reliability Analysis (SRA) is a useful tool in structural engineering. Uncertainty in input parameters and model uncertainties in the analysis predictions are explicitly modelled by random variables. With this methodology, the uncertainties involved are handled in a consistent and transparent way. Compared to a deterministic analysis, SRA provides improved insight in how the various uncertainties involved influence the results. The main results from SRA is the calculated probability of structural failure, but other useful results such as uncertainty importance factors and design points being the most likely combination of all variables at failure represent helpful information. The present paper illustrates some the features using SRA for two different types of application. The first application is the use of SRA as a tool for code calibration and the second shows the application of SRA to a problem where common practice is likely to be rather conservative and therefore leading to unacceptable results, but where the degree of conservatism is not known. Two examples are chosen to illustrate code calibration; i.e. hull girder ultimate limit state (ULS) for tankers and ULS for mooring design in the ULS for floating offshore vessels. Code calibration involves both SRA and design analysis following the code. It is shown how the design analysis can be modified in order to better reflect a chosen target reliability level across a selected set of test cases representative for what the code should cover. Fatigue of subsea wellhead systems is selected as an example of a special case when application of existing rules may lead to unsatisfactory results which are likely to be rather conservative. It is shown how results can be presented in terms of the accumulated probability of fatigue failure as a function of time. This may be a more suitable basis for decision making than a calculated fatigue life from a standard analysis. It is also illustrated how importance factors from the SRA can be used as guidance on how to prioritize effort in order to improve prediction of the fatigue damage. The present paper is not intended to be detailed in all input and analysis methodology, but draw the attention towards the possibilities and benefits of applying SRA in structural engineering, where the examples are used to illustrate this potential.

scholarly journals Reliability of Buried Pipes in Heterogeneous Soil Subjected to Seismic Loads

2021 ◽  
Vol 11 (1) ◽  
pp. 6708-6713
Author(s):  
H. Benzeguir ◽  
S. M. Elachachi ◽  
D. Nedjar ◽  
M. Bensafi
Keyword(s):  
Structural Reliability ◽  
Limit State ◽  
Bending Moment ◽  
Longitudinal Direction ◽  
Point Of View ◽  
Ultimate Limit State ◽  
Buried Pipe ◽  
Limit States ◽  
Ground Acceleration ◽  
Buried Pipes

Dysfunctions and failures of buried pipe networks, like sewer networks, are studied in this paper from the point of view of structural reliability and heterogeneity of geotechnical conditions in the longitudinal direction. Combined soil spatial variability and Peak Ground Acceleration (PGA) induce stresses and displacements. A model has been developed within the frame of geostatistics and a mechanical description of the soil–structure interaction of a set of buried pipes with connections resting on the soil by a two-parameter model (Pasternak model). Structural reliability analysis is performed considering two limit states: Serviceability Limit State (SLS), related to large "counter slope" in a given pipe, and Ultimate Limit State (ULS), corresponding to bending moment.

scholarly journals Service Life Prediction of Precast Concrete Structures Exposed to Chloride Environment

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Dawei Zhang ◽  
Yu Zeng ◽  
Mingshan Fang ◽  
Weiliang Jin
Keyword(s):  
Shear Failure ◽  
Precast Concrete ◽  
Probability Model ◽  
Limit State ◽  
Concrete Structures ◽  
Seismic Load ◽  
Ultimate Limit State ◽  
Interface Shear ◽  
Serviceability Limit State ◽  
Corrosion Initiation

Chloride-induced corrosion is widely accepted as one of the primary causes of premature deterioration for concrete structures in marine or deicing salt environment. For precast concrete (PC) structures, such durability problems may even be severer because defects in joint areas, e.g., cracks caused by grout shrinkage and improper construction, can accelerate chloride ion transportation process and may cause the interface shear failure when subjected to seismic load. By applying the path probability model (PPM) and reliability theory, a probabilistic framework was proposed to predict three limit states of PC structures, including corrosion initiation, serviceability limit state, and ultimate limit state. Using Monte Carlo simulation, a beam-to-column joint was further analyzed to illustrate the differences between PC structures and those cast in situ. The analysis indicates that corrosion initiation and serviceability limit state are sensitive to chloride diffusivity at connection area, and the higher pitting factor can significantly influence the bearing capacities of PC structures.

Calibration of Load and Resistance Factors for the Design of Cable Members in Cable-supported Bridges Using Optimization of Strength

2019 ◽  
Author(s):  
Ho Hyun Lee ◽  
Hae Sung Lee
Keyword(s):  
Limit State ◽  
Target Strength ◽  
State Function ◽  
Reliability Indices ◽  
Resistance Factors ◽  
Reliability Level ◽  
Code Calibration ◽  
Structural Types ◽  
Nominal Strength ◽  
Load And Resistance Factors

<p>This proceeding presents the calibration process of load and resistance factors for the design of cable members under a gravitational loads-governed limit state adopting optimization scheme. In reliability-based bridge design code, although the cable members show various behavior depending on the structural types of bridges, a proper reliability level should be satisfied by the load and resistance factors. A cable is a nonlinear component, thus tension of it also shows nonlinear characteristics. In this study, the limit state function is linearized, and the tension of each load component is normalized by total nominal tension. With the purpose of performing code calibration independent of structural types of bridges, the normalized tensions are parameterized by three load ratios. The target reliability indices of cable members are determined considering results of reliability analyses of existing cable-supported bridges in South Korea, and a target strength, which satisfies the target reliability indices exactly, is evaluated. Optimization problem to minimize an error between the target strength and nominal strength, which is calculated by the load and resistance factors, is defined, and optimal values of the factors are calibrated. Reliability analyses for the strength calculated from the optimal factors are performed and it is verified that the factors can lead to the design with a uniform reliability level.</p>

DESIGN OF BOLTED CONNECTIONS SUBJECT TO TORSION AND SHEAR IN THE ULTIMATE LIMIT STRESS STATE

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Mohamed S. Abu-Yosef ◽  
Ezzeldin Y. Sayed-Ahmed ◽  
Emam A. Soliman
Keyword(s):  
Failure Modes ◽  
Focal Point ◽  
Design Method ◽  
Limit State ◽  
Bending Moment ◽  
Steel Structures ◽  
Ultimate Limit State ◽  
Shear Forces ◽  
Limit States ◽  
Ultimate Limit

Steel connections transferring axial and shear forces in addition to bending moment and/or torsional moment are widely used in steel structures. Thus, design of such eccentric connections has become the focal point of any researches. Nonetheless, behavior of eccentric connections subjected to shear forces and torsion in the ultimate limit state is still ambiguous. Most design codes of practice still conservatively use the common elastic analysis for design of the said connections even in the ultimate limit states. Yet, there are some exceptions such as the design method proposed by CAN/CSA-S16-14 which gives tabulated design aid for the ultimate limit state design of these connections based on an empirical equation that is derived for ¾ inch diameter A325 bearing type bolts and A36 steel plates. It was argued that results can also be used with a margin of error for other grade bolts of different sizes and steel of other grades. As such, in this paper, the performance of bolted connection subject to shear and torsion is experimentally investigated. The behavior, failure modes and factors affecting both are scrutinized. Twelve connections subject to shear and torsion with different bolts configurations and diameters are experimentally tested to failure. The accuracy of the currently available design equations proposed is compared to the outcomes of these tests.

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