Analysis and design of rehabilitated built-up hybrid steel compression members

2008 ◽  
Vol 35 (12) ◽  
pp. 1375-1387 ◽  
Author(s):  
Katherine K.-W. Shek ◽  
F. Michael Bartlett
Keyword(s):  
Numerical Analysis ◽  
Analysis Model ◽  
Dead Load ◽  
Design Code ◽  
Analysis And Design ◽  
Compression Members ◽  
Current Design ◽  
Parametric Studies ◽  
Compressive Resistance ◽  
Cover Plates

Compression members in steel bridges designed before 1960 may be deficient according to current design code requirements and so require strengthening. This paper explores the response of steel wide-flange columns reinforced with new steel flange cover plates, accounting for: residual and locked-in dead-load stresses; different yield strengths of the original W shape and the new cover plates; initial out-of-straightness; and load eccentricity at the member ends. A refined numerical analysis model is formulated and validated that computes the compressive resistance from principles of equilibrium, compatibility, and force–deformation relationships. Parametric studies conducted indicate that the capacity of the reinforced column is relatively insensitive to the magnitude of the locked-in dead-load stress in the original member, and that the strong axis capacity is insensitive to the magnitude of the residual stresses in the original member. A preliminary approach for designing strengthening for these members is presented and illustrated with an example calculation.

Estimation of capacity of eccentrically loaded single angle struts with decision trees

2019 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Saha Dauji
Keyword(s):  
Decision Trees ◽  
Decision Rules ◽  
Practical Implementation ◽  
Design Code ◽  
Design Standards ◽  
Analysis And Design ◽  
Transmission Towers ◽  
Compression Members ◽  
Comparable Accuracy ◽  
Better Than

Single angle struts are used as compression members for many structures including roof trusses and transmission towers. The exact analysis and design of such members is challenging due to various uncertainties such as the end fixity or eccentricity of the applied loads. The design standards provide guidelines that have been found inaccurate towards the conservative side. Artificial Neural Networks (ANN) have been observed to perform better than the design standards, when trained with experimental data and this has been reported literature. However, practical implementation of ANN poses problem as the trained network as well as the knowhow regarding the application should be accessible to practitioners. In another data-driven tool, the Decision Trees (DT), the practical application is easier as decision based rules are generated, which are readily comprehended and implemented by designers. Hence, in this paper, DT was explored for the evaluation of capacity of eccentrically loaded single angle struts and was found to be robust and yielded comparable accuracy as ANN, and better than design code (AISC). This has enormous potential for easy and straightforward implementation by practicing engineers through the logic based decision rules, which would be easily programmable on computer. For this application, use of dimensionless ratios as inputs for the development of DT was found to yield better results when compared to the approach of using the original variables as inputs.

Structural Integrity for Nuclear Power Plant Against Excessive Load on Design Extension Condition

2013 ◽  
Author(s):  
Daigo Watanabe ◽  
Kiminobu Hojo
Keyword(s):  
Nuclear Power ◽  
Structural Integrity ◽  
Safety Factors ◽  
Design Code ◽  
Acceptance Criteria ◽  
Integrity Assessment ◽  
Current Design ◽  
Factor Design ◽  
Excessive Load ◽  
Load And Resistance Factor

This paper introduces an example of structural integrity evaluation for Light Water Reactor (LWR) against excessive loads on the Design Extension Condition (DEC). In order to assess the design acceptance level of DEC, three acceptance criteria which are the stress basis limit of the current design code, the strain basis limit of the current design code and the strain basis limit by using Load and Resistance Factor Design (LRFD) method were applied. As a result the allowable stress was increased by changing the acceptance criteria from the stress basis limit to the strain basis limit. It is shown that the practical margin of the LWR’s components still keeps even on DEC by introducing an appropriate criterion for integrity assessment and safety factors.

Factored axial compressive resistance of schifflerized angles

1991 ◽  
Vol 18 (6) ◽  
pp. 926-932 ◽  
Author(s):  
Seshu Madhava Rao Adluri ◽  
Murty K. S. Madugula
Keyword(s):  
Key Words ◽  
Design Method ◽  
Design Criteria ◽  
Design Practice ◽  
Buckling Mode ◽  
Flexural Buckling ◽  
Mode Of Failure ◽  
Current Design ◽  
Similarities And Differences ◽  
Compressive Resistance

The concept of schifflerization of 90° equal-leg angle is presented and its application in triangular-base latticed steel towers is explained. The similarities and differences between schifflerized angles and regular 90° angles are discussed. The current design practice for schifflerized angles is reviewed and its limitation is highlighted. A design method which includes the effect of the torsional-flexural buckling mode of failure is proposed. For ready use of designers, the factored axial compressive resistances of schifflerized angles are tabulated for both the present and proposed design methods. Key words: buckling, compressive resistance, design criteria, schifflerized angles, stability, standards, steel, struts, towers, guyed towers.

On Numerical Simulation of the Stepped Soil-Nail Wall

2013 ◽  
Vol 353-356 ◽  
pp. 692-695
Author(s):  
Chang Zhi Zhu ◽  
Quan Chen Gao
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Internal Force ◽  
Numerical Results ◽  
Analysis Model ◽  
Foundation Pit ◽  
Soil Nails ◽  
Soil Nail ◽  
Soil Nail Wall ◽  
Design And Construction

Based on an Engineering Example which was supported by the stepped soil-nail wall, a numerical analysis model was established by FLAC3D,and the process of the excavation and supporting was simulated, and the numerical results of the soil nails internal force and foundation pit deformation were obtained. The simulated result was consistent with the measured results. It shows that the method of FLAC3D numerical analysis can be used to the numerical analysis of foundation pit excavation and supporting, and it will provide the basis for the design and construction of practice project.

Numerical analysis and design of a new traveling-wave photodetector with an asymmetric I-layer cross section

2003 ◽  
Vol 9 (3) ◽  
pp. 770-775 ◽  
Author(s):  
Soon-Cheol Kong ◽  
Seong-Hae Ok ◽  
Young-Wan Choi ◽  
Joong-Seon Choe ◽  
Yong-Hwan Kwon ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Traveling Wave ◽  
Analysis And Design

Experimental Study and Finite Analysis on Flexural Capacity of Laminated Glass

2011 ◽  
Vol 243-249 ◽  
pp. 258-262
Author(s):  
Jun Chen ◽  
Jia Lv ◽  
Qi Lin Zhang ◽  
Zhi Xiong Tao ◽  
Jun Chen
Keyword(s):  
Experimental Results ◽  
Laminated Glass ◽  
Test Results ◽  
Design Code ◽  
Flexural Capacity ◽  
Equivalent Thickness ◽  
High Rise ◽  
Safety Glass ◽  
Current Design ◽  
Good Agreement

Laminated glass has been increasing widely used in high rise buildings as a kind of safety glass in recent years. So we should analyze its material property. In this paper, we use flexural experiments and ANSYS program to analyze the main factors that affect the flexural capacity of the laminated glass. The test results show that the flexural capacity is closely related to film. And the ANSYS program had got good agreement with the experimental results. Comparison of experimental results with calculated ones indicates that the current design code will lead to conservative results and the equivalent thickness of laminated glasses provided in the code should be further discussed.

Determination of the Thermal Properties of a PCB by Coupled Numerical and Experimental Approach

2020 ◽  
Author(s):  
Yener Usul ◽  
Mustafa Özçatalbaş
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Numerical Analysis ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Thermal Analyses ◽  
Analysis Model ◽  
Linear Temperature ◽  
Coefficient Of Thermal Conductivity

Abstract Increasing demand for usage of electronics intensely in narrow enclosures necessitates accurate thermal analyses to be performed. Conduction based FEM (Finite Element Method) is a common and practical way to examine the thermal behavior of an electronic system. First step to perform a numerical analysis for any system is to set up the correct analysis model. In this paper, a method for obtaining the coefficient of thermal conductivity and specific heat capacity of a PCB which has generally a complex composite layup structure composed of conductive layers, and dielectric layers. In the study, above mentioned properties are obtained performing a simple nondestructive experiment and a numerical analysis. In the method, a small portion of PCB is sandwiched from one side at certain pressure by jaws. A couple of linear temperature profiles are applied to the jaws successively. Unknown values are tuned in the analysis model until the results of FEM analysis and experiment match. The values for the coefficient of thermal conductivity and specific heat capacity which the experiment and numerical analysis results match can be said to be the actual values. From this point on, the PCB whose thermal properties are determined can be analyzed numerically for any desired geometry and boundary condition.

Applications of Symbolic Computing for Numerical Analysis of Mechanical Systems

1989 ◽  
Author(s):  
H. Ashrafiuon ◽  
N. K. Mani
Keyword(s):  
Numerical Analysis ◽  
Optimal Design ◽  
System Dynamics ◽  
Multibody System ◽  
Computing System ◽  
General Purpose ◽  
Kinematic Constraints ◽  
Symbolic Computing ◽  
Analysis And Design ◽  
Construct System

Abstract The symbolic computing system MACSYMA is used to automatically generate the explicit equations necessary to represent the kinematic constraints and system dynamics and to compute the design sensitivities for optimal design of any multibody system. The logic to construct system matrices and vectors involved in the analysis and design equations is implemented as general purpose MACSYMA programs. All necessary manipulations are performed by MACSYMA and the equations are output as FORTRAN statements that can be compiled and executed. This approach results in a computational saving of up to 95% compared to using a general purpose programs. The approach is general in nature and is applicable to any multibody system. Examples are presented to demonstrate the effectiveness of the approach.

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