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.

Strengthening Space Trusses by Diagonal Removal

1993 ◽  
Vol 8 (4) ◽  
pp. 231-239 ◽  
Author(s):  
Mousa Tabatabaei ◽  
Cedric Marsh
Keyword(s):  
Carrying Capacity ◽  
Load Capacity ◽  
Maximum Load ◽  
Load Carrying Capacity ◽  
Shear Forces ◽  
Equitable Distribution ◽  
Space Truss ◽  
Load Carrying ◽  
Space Trusses ◽  
Selection Of

Ideally a space truss is composed of bars each of which is suited to the load it carries. In practice, however, it is more convenient to use a limited number of bar sizes, thus only a few of the members will be fully stressed when the maximum load capacity of the space truss is reached. In order to effect a more equitable distribution of forces between chords of equal size such that more chord members are loaded close to their capacity, selected diagonals are removed to control the path followed by the shear forces, and thereby control the forces entering the chords. In this paper the effect of diagonal removal on space trusses is demonstrated and a method for selection of the diagonals whose removal gives optimum increase in the load carrying capacity of a space truss is described.

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.

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.

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.

scholarly journals Numerical Investigation of Load-Carrying Capacity of GFRP-Reinforced Rectangular Concrete Members Using CDP Model in ABAQUS

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Ali Raza ◽  
Qaiser uz Zaman Khan ◽  
Afaq Ahmad
Keyword(s):  
Carrying Capacity ◽  
Control Sample ◽  
Critical Parameters ◽  
Elastoplastic Material ◽  
Load Carrying Capacity ◽  
Element Analysis ◽  
Gfrp Bars ◽  
Concrete Members ◽  
Load Carrying ◽  
Steel Bars

The present work demonstrates the nonlinear finite element analysis (NLFEA) of 13 concentrically and eccentrically loaded short rectangular concrete column specimens reinforced with GFRP and conventional steel bars. GFRP bars are lightweight having the high tensile strength and high corrosion resistance. An NLFEA model for the rectangular concrete specimens was developed using the commercial software ABAQUS Standard and calibrated for different materials and geometric parameters based on the previous experimental test results of the studied specimen. The behavior of reinforced concrete was modelled using the concrete damaged plasticity (CDP) model, the behavior of steel bars was simulated as a bilinear elastoplastic material, and the GFRP bars were considered as a linear elastic material. After the calibration of CDP parameters, the control sample was used for the further numerical parametric analysis to investigate the effect of critical parameters, i.e., the area of concrete (Ac), the compressive strength of concrete (fc′), and the ratio of longitudinal reinforcement (ρl) and transverse reinforcement (ρt) on the load-carrying capacity of columns. The results show that the selected NLFEA model can simulate the behavior of columns accurately and there was good agreement of numerical results obtained from ABAQUS Standard with the experimental results.

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