scholarly journals Load carrying capacity of partially encased columns for different fire ratings

Fire Research ◽  
2016 ◽  
Author(s):  
Abdelkadir Fellouh ◽  
Nourredine Benlakehal ◽  
Paulo Piloto ◽  
Ana Ramos ◽  
Luís Mesquita
Keyword(s):  
Fire Resistance ◽  
Carrying Capacity ◽  
Three Dimensional ◽  
Thermal Inertia ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Three Dimensional Model ◽  
Load Carrying ◽  
Solution Methods ◽  
Two Parameters

Partially encased columns have significant fire resistance in comparison with steel bare columns. However, it is not possible to assess the fire resistance of such members simply by considering the temperature of the steel. The presence of concrete increases the mass and thermal inertia of the member and the variation of temperature within the cross section, in both the steel and concrete components. The annex G of EN1994-1-2:20051 allows to calculate the load carrying capacity of partially encased columns, for a specific fire rating time, considering the balanced summation model. New formulas will be proposed to calculate the plastic resistance to axial compression and the effective flexural stiffness. These two parameters are used to determine the buckling resistance. The finite element method is used to compare the results for the elastic critical load and the load carrying capacity of partially encased columns for different fire ratings of 30 and 60 min. This work compares the results from both solution methods, provides the validation of the three-dimensional model and demonstrates that a new design curve should be used for the buckling analysis of partially encased columns.

scholarly journals Behaviour of eccentrically loaded prestressed stayed columns with circular hollow sections

2020 ◽  
Vol 23 (13) ◽  
pp. 2813-2821
Author(s):  
Peter Hyman ◽  
Adelaja Israel Osofero
Keyword(s):  
Carrying Capacity ◽  
Three Dimensional ◽  
Load Carrying Capacity ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Interactive Mode ◽  
Load Carrying ◽  
Three Dimensional Models ◽  
Twisting Effect

The behaviour of axially loaded prestressed stayed columns is a commonly studied area. Despite the fact that load eccentricity in columns is commonplace in practice, the amount of investigation into these systems under eccentric loading is limited. This study employed finite element analysis to investigate the interactive post-buckling behaviour of prestressed stayed columns. Critical imperfection combination with respect to the load carrying capacity was established and a comparison of a planar and a three-dimensional model was carried out to investigate key differences in the models. In this work, it has been shown that the load carrying capacity of eccentrically loaded columns can be significantly reduced when buckling in interactive mode is observed. Furthermore, it was established that increase in eccentricity results in a decrease in load carrying capacity of columns for both planar and three-dimensional models. However, a major difference between the models is the twisting effect exhibited in the three-dimensional model under out-of-plane eccentric loading. This work highlights the importance of carefully designing prestressed stayed columns’ connections to minimise loading eccentricity as it has been shown that the benefit of employing these systems over unstayed columns reduces with increasing load eccentricity.

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

Determination of the Load Carrying Capacity of Honeycomb Panels at Fixing Points under an External Load

2020 ◽  
Vol 299 ◽  
pp. 1184-1189
Author(s):  
V.V. Zhukov ◽  
Anton V. Eremin ◽  
D.V. Stepanec
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Element Model ◽  
Carrying Capacity ◽  
External Load ◽  
Element Model ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Load Carrying ◽  
Honeycomb Panel

In this article, the object of study is a three–layer honeycomb panel with fixing elements (FE), which are used for transporting the panel, and fixing it to the spacecraft. The goal of the work is to determine experimentally the load carrying capacity of the fixing elements under various types of loading, to determine the load carrying capacity of the honeycomb panel of the spacecraft at fixing points and further comparison of the experimental results with the finite element method results calculated by MSC.Patran / Nastran. A method for conducting static tests of fixing elements of a spacecraft honeycomb panel under an external load is described, a description of computer technology of a finite–element solution to the problem of static strength of a honeycomb panel structure in the MSC.Patran environment is presented, and a finite–element model of a honeycomb panel is designed. An assessment of the strength of a three–layer structure at fixing points was carried out, followed by validation of the finite–element model of a honeycomb panel. On the basis of the validated model, the evaluation of the strength of the honeycomb structure was carried out; based on results obtained, the conclusion has been made about the convergence of the results by the finite element method with the results obtained during the experiment.

SEARCH FOR THE MOST USEFUL GEOMETRY OF AN ACOUSTIC JOURNAL BEARING

Tribologia ◽  
2018 ◽  
Vol 273 (3) ◽  
pp. 15-66 ◽  
Author(s):  
Rafał GAWARKIEWICZ
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Simulations ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Squeeze Film ◽  
Acoustic Levitation ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Load Carrying

Computer simulations of a number of journal bearing’s geometries utilising acoustic levitation were carried out. The choice of the best geometry depended on the ability of a deformed shape, created by piezo-electric elements, to facilitate squeeze film ultrasonic levitation, and also to create three evenly distributed diverging aerodynamic gaps. Deformations of analysed variants of the bearing’s shape were generated by numerical simulations utilising the finite element method. For the chosen shapes of geometry, prototype bearings were made and their usefulness verified experimentally. As a result, the bearing with the highest load carrying capacity was identified.

Single-angle compression members welded by one leg to a gusset plate. II. A parametric study and design equation

1998 ◽  
Vol 25 (3) ◽  
pp. 585-594 ◽  
Author(s):  
Murray C Temple ◽  
Sherief SS Sakla
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Design Equation ◽  
Rigid Support ◽  
The Finite Element Method ◽  
Gusset Plate ◽  
Compression Members ◽  
Load Carrying

Single-angle compression members are complex members to analyze and design. The two generally accepted design procedures, the simple-column and the beam-column approaches, in general, underestimate the load-carrying capacity of single-angle compression members welded by one leg to a gusset plate fixed to a rigid support. One of the reasons is that these approaches do not properly account for the end constraint provided by the gusset plate. The effective length factor can be adjusted, but this is difficult to do as the end restraint is not easy to evaluate in many practical cases. Another reason is that these approaches are not based on a rational understanding of the failure mechanism of these members. An experimental program confirmed that the finite element method can be used, with a reasonable degree of accuracy, to predict the behavior and load-carrying capacity of single-angle compression members welded by one leg to a gusset plate fixed to a rigid support. The finite element method was used to study some 1800 different combinations of parameters. It was found that out-of-straightness, residual stresses in the angle section, Young's modulus of elasticity, and the unconnected gusset plate length do not have a great effect on the load-carrying capacity. The most significant parameter is the gusset plate thickness with the gusset plate width being the second most important parameter. An empirical design equation is proposed.Key words: angles, buckling, columns (structural), compressive resistance, design equation, gusset plates.

Geometry Optimization of Textured Three-Dimensional Micro- Thrust Bearings

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
C. I. Papadopoulos ◽  
E. E. Efstathiou ◽  
P. G. Nikolakopoulos ◽  
L. Kaiktsis
Keyword(s):  
Carrying Capacity ◽  
Stokes Equations ◽  
Load Capacity ◽  
Three Dimensional ◽  
Load Carrying Capacity ◽  
Thrust Bearings ◽  
Micro Channels ◽  
Wide Range ◽  
Load Carrying ◽  
Bearing Load

This paper presents an optimization study of the geometry of three-dimensional micro-thrust bearings in a wide range of convergence ratios. The optimization goal is the maximization of the bearing load carrying capacity. The bearings are modeled as micro-channels, consisting of a smooth moving wall (rotor), and a stationary wall (stator) with partial periodic rectangular texturing. The flow field is calculated from the numerical solution of the Navier-Stokes equations for incompressible isothermal flow; processing of the results yields the bearing load capacity and friction coefficient. The geometry of the textured channel is defined parametrically for several width-to-length ratios. Optimal texturing geometries are obtained by utilizing an optimization tool based on genetic algorithms, which is coupled to the CFD code. Here, the design variables define the bearing geometry and convergence ratio. To minimize the computational cost, a multi-objective approach is proposed, consisting in the simultaneous maximization of the load carrying capacity and minimization of the bearing convergence ratio. The optimal solutions, identified based on the concept of Pareto dominance, are equivalent to those of single-objective optimization problems for different convergence ratio values. The present results demonstrate that the characteristics of the optimal texturing patterns depend strongly on both the convergence ratio and the width-to-length ratio. Further, the optimal load carrying capacity increases at increasing convergence ratio, up to an optimal value, identified by the optimization procedure. Finally, proper surface texturing provides substantial load carrying capacity even for parallel or slightly diverging bearings. Based on the present results, we propose simple formulas for the design of textured micro-thrust bearings.

Polymer Composite with Sisal Fiber Used for Node Reinforce in Space-Truss with Stamped Connection

2015 ◽  
Vol 719-720 ◽  
pp. 202-205
Author(s):  
Cleirton A.S. Freitas ◽  
Mucio M.S. Nobrega ◽  
Édipo A. Bezerra ◽  
Otávio R.O. Cavalcante
Keyword(s):  
Polymer Composite ◽  
Carrying Capacity ◽  
Three Dimensional ◽  
Sisal Fiber ◽  
Load Carrying Capacity ◽  
Space Truss ◽  
Load Carrying ◽  
Steel Bars ◽  
Space Trusses

Space trusses are three-dimensional structures made of steel bars very frequently used at the roof construction. The bars, with tubular section, are linking in the 3D form by connections. There are several types of connections to attach these members. The most economical connection is the staking end-flattened connection, also called typical node. The reduced cost and the fast assemblage of the truss are among their advantages. However, such connections present disadvantages like eccentricities and stiffness weakening of the tubular members. This research presents suggestions of reinforcement and constructive correction in the connection in order to increase its capacity. The base for this is the reduction of the eccentricity in typical node applying the spacer. This spacer was made by polymer composite with sisal fiber. In this work was developed experimental lab tests in prototypes with fifty four meters square of area. The results show an increase of 26% for collapse in the truss load carrying capacity when the suggested changes proposed in this article are used for the staking end-flattened connections.

Assessment of Load Carrying Capacity for Concrete Rectangle Section Simple Beam Subjected to Fire

2012 ◽  
Vol 204-208 ◽  
pp. 2841-2845
Author(s):  
Gang Zhang ◽  
Shuan Hai He ◽  
Hong Jun Guo
Keyword(s):  
Fire Resistance ◽  
Carrying Capacity ◽  
Concrete Beam ◽  
Fire Hazard ◽  
Assessment Method ◽  
Concrete Cover ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Cover Thickness ◽  
Beam Bridge

The assessment method of load carrying capacity for concrete rectangle section simple beam subjected to fire was presented. Comprehensively considering influencing parameters, load carrying capacity for reinforced concrete rectangle section simple beam was analyzed in a fire hazard by using numerical simulation program. A series of safety assessment regularities for the reinforcement pieces was put forward subjected to fire. The studied results indicate that: the ultimate moment for reinforcement concrete beam bridge tends to decrease linearly after 40 minute, the fire resistance of the reinforcement concrete rectangle section simple beam increase linearly with the increment of the concrete cover thickness; Therefore, the increment of concrete protective thickness is effective to fire resistance and safety grade for the reinforcement concrete beam.

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