scholarly journals Bearing Capacity Model of Corroded RC Eccentric Compression Columns Based on Hermite Interpolation and Fourier Fitting

2018 ◽  
Vol 9 (1) ◽  
pp. 24 ◽  
Author(s):  
Jingzhou Xin ◽  
Jianting Zhou ◽  
Fengbin Zhou ◽  
Simon Yang ◽  
Yi Zhou
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Hermite Interpolation ◽  
Measured Data ◽  
Small Scale ◽  
Pure Bending ◽  
Eccentric Compression ◽  
Starting Point ◽  
Hermite Interpolating Polynomial ◽  
Fourier Function

With an extension in service years, bridges inevitably suffer from performance deterioration. Columns are the main components of bridge structures, which support the superstructure. The damage of pier columns is often more harmful to bridges than that of other components. To accurately evaluate the time-varying characteristics of corroded columns, this paper proposes a new model for the bearing capacity evaluation of deteriorated reinforced concrete (RC) eccentric compression columns based on the Hermite interpolation and Fourier function. Firstly, the axial compression point, the pure bending point and the balanced failure point were selected as the basic points, and the deteriorated strength of these basic points was calculated by considering factors such as concrete cracking, reduction of reinforcement area, buckling of the steel bar, bond slip and strength reduction of confined concrete. After that, the interpolation points were generated by a piecewise cubic Hermite interpolating polynomial, and the explicit expression of the interpolation points fitting function was realized by the trigonometric Fourier series model. Finally, comparison studies based on measured data from forty-five corroded RC eccentric compression columns were conducted to investigate the accuracy and efficiency of the proposed method. The results show that: (1) the prediction results for bearing capacity of corroded RC columns are in good agreement with the measured data, with the average ratio of predicted results to test results at 1.06 and the standard deviation at 0.14; (2) the proposed model unifies the three stress states of axial compression, eccentric compression and pure bending, and is consistent with the continuum mechanics characteristics; (3) the decrements of axial load carrying capacity for 10% and 50% of the corrosion rate are 31.4% and 45.2%, while in flexure they are 25.4% and 77.4%, respectively; and (4) the test data of small-scale specimens may overestimate the negative effect of corrosion on the bearing capacity of actual structures. The findings in this paper could lay a solid starting point for structural life prediction technologies based on nondestructive testing.

Study on the Bearing Capacity and Ductility of Steel Reinforced Concrete Cross-Shaped Columns

2011 ◽  
Vol 243-249 ◽  
pp. 15-19 ◽  
Author(s):  
Zhe Li ◽  
Shao Ji Chen ◽  
Jing Xu ◽  
Ye Ni Wang ◽  
Cui Ping Zhang
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Cross Section ◽  
Compression Ratio ◽  
Computer Data ◽  
Steel Reinforced Concrete ◽  
Axial Compression Ratio ◽  
Eccentric Compression ◽  
Curvature Ductility

Compared with reinforced concrete shaped columns, bearing capacity and ductility of steel reinforced concrete shaped columns are significantly improved, so it is with theoretical significance and practical application of value to research. Based on the plain cross section presume, with material cross-section boundary calculation unit, 15 steel reinforced concrete cross-shaped columns(SRCCSC) have made nonlinear full-rang numerical analysis. It demonstrates that the most adverse curvature ductility load angle of SRCCRSC is 45°.Loading angle (), axial compression ratio (n), and the ratio of spacing and diameter of longitudinal reinforcements (s/d) are the principal factors in curvature ductility of SRCCSC subjected to biaxial eccentric compression. Under the most unfavorable loading angle, through a regression analysis of curvature ductility computer data of 150 cross-shaped columns with 8mm stirrups diameter and 150 columns with 10mm stirrups diameter, it can be obtained with the relationship betweenand axial compression ration,s/d, of SRCCSC subjected to biaxial eccentric compression.

scholarly journals Bearing Capacities of Different-Diameter Concrete-Filled Steel Tubes under Axial Compression

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Wenjing Wang ◽  
Zhenyun Tang ◽  
Zhenbao Li ◽  
Hua Ma
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Peak Load ◽  
Steel Tube ◽  
Specimen Size ◽  
Small Scale ◽  
Strengthening Effect ◽  
Steel Tubes ◽  
Specimen Diameter ◽  
Concrete Filled Steel Tubes

The bearing capacities of concrete-filled steel tubes are normally derived through experiments with small-scale specimens, but it is uncertain whether such derivations are appropriate for the much larger components used in practical engineering. This study therefore investigates the effect of different diameters (219, 426, 630, and 820 mm) on the axial compression of short concrete columns in steel (Q235) tubes. It is found that the peak nominal stress decreases with increasing specimen size and that the axial bearing capacity is determined by three separate components: the cylinder compressive strength of the concrete, the improvement in strength due to the confining effect of the steel tube, and the longitudinal strength of the steel tube. At peak load, increases in the specimen diameter reduce the hoop stresses in the steel tube, thereby reducing the strengthening effect of confinement. Vertical stress in the steel tube is increased with diameter; therefore, the axial bearing capacity of the steel tube is directly related to the specimen size. Size effect coefficients for these three aspects of bearing capacity are defined and used to develop a size-dependent model for predicting the axial bearing capacity of large, concrete-filled steel tubes. The model is then validated against experimental data.

Comparison of Bearing Capacity of H-Shaped Members with Corrugated Web of Different Wave Forms

2013 ◽  
Vol 831 ◽  
pp. 181-185
Author(s):  
Li Li Wu ◽  
Kai Feng Guo ◽  
Bi De Li ◽  
Xiao Lin Fu ◽  
Zhen Jin Su ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Loading Condition ◽  
Sine Wave ◽  
Pure Bending ◽  
Conversion Method ◽  
Corrugated Web ◽  
Wave Forms

In this paper, according to the method of keeping wavelength the same, while the amplitude and unfolding length approximately equivalent, trapezoidal wave is transformed into sine wave. On this base,the bearing capacity under axial compression, pure bending, shear of corrugated web member of two kinds of wave forms converted respectively are compared. Results show that under the same loading condition, stress distribution of the two kinds of corrugated web member section is basically the same. By using different waveform conversion method presented in this paper, the equivalent conversion between different corrugated web member can be easily realized.

Indirect Assessment of Attitudes with Response-Time-Based Measures

2006 ◽  
Vol 37 (3) ◽  
pp. 131-139 ◽  
Author(s):  
Juliane Degner ◽  
Dirk Wentura ◽  
Klaus Rothermund
Keyword(s):  
Social Cognitive ◽  
Incremental Validity ◽  
Self Report ◽  
Small Scale ◽  
Implicit Measures ◽  
Scale Theory ◽  
Starting Point ◽  
Self Reports ◽  
Predicting Behavior ◽  
Social Cognitive Theories

Abstract: We review research on response-latency based (“implicit”) measures of attitudes by examining what hopes and intentions researchers have associated with their usage. We identified the hopes of (1) gaining better measures of interindividual differences in attitudes as compared to self-report measures (quality hope); (2) better predicting behavior, or predicting other behaviors, as compared to self-reports (incremental validity hope); (3) linking social-cognitive theories more adequately to empirical research (theory-link hope). We argue that the third hope should be the starting point for using these measures. Any attempt to improve these measures should include the search for a small-scale theory that adequately explains the basic effects found with such a measure. To date, small-scale theories for different measures are not equally well developed.

Effect of Axial Compression Ratio on Ductility and Bearing Capacity of Specially Shaped Columns with HRB500 Reinforcement

2012 ◽  
Vol 204-208 ◽  
pp. 1066-1069
Author(s):  
Yan Jun Li ◽  
Ping Liu
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Compression Ratio ◽  
Ultimate Load ◽  
Deformation Capacity ◽  
Displacement Ductility ◽  
Yield Load ◽  
Axial Compression Ratio ◽  
Low Cyclic Loading ◽  
Specially Shaped Column

Four specially shaped columns with HRB500 reinforcement were tested under low cyclic loading. The hysteretic curve, yield load, ultimate load, displacement ductility and rigidity degradation were compared in order to research the effect of axial compression ratio on ductility and bearing capacity of specially shaped column with HRB500 reinforcement. It is shown that the axial compression ratio has greater influence on ductility and bearing capacity. With the increase of axial compression ratio, the bearing capacity of HRB500 reinforcement concrete specially shaped column can be enhanced while the deformation capacity becomes worse. The hysteretic characteristic of specially shaped columns with HRB500 reinforcement is improved and the stiffness degeneration becomes slow with the decrease of axial compression ratio.

scholarly journals Small-Scale Spectrum of a Scalar Field in Water: The Batchelor and Kraichnan Models

2011 ◽  
Vol 41 (11) ◽  
pp. 2155-2167 ◽  
Author(s):  
Xavier Sanchez ◽  
Elena Roget ◽  
Jesus Planella ◽  
Francesc Forcat
Keyword(s):  
Scalar Field ◽  
Thermal Gradient ◽  
Theoretical Models ◽  
Measured Data ◽  
Small Scale ◽  
Temperature Profiles ◽  
One Dimensional ◽  
Kraichnan Model ◽  
The One ◽  
Rate Of Dissipation

Abstract The theoretical models of Batchelor and Kraichnan, which account for the smallest scales of a scalar field passively advected by a turbulent fluid (Prandtl > 1), have been validated using shear and temperature profiles measured with a microstructure profiler in a lake. The value of the rate of dissipation of turbulent kinetic energy ɛ has been computed by fitting the shear spectra to the Panchev and Kesich theoretical model and the one-dimensional spectra of the temperature gradient, once ɛ is known, to the Batchelor and Kraichnan models and from it determining the value of the turbulent parameter q. The goodness of the fit between the spectra corresponding to these models and the measured data shows a very clear dependence on the degree of isotropy, which is estimated by the Cox number. The Kraichnan model adjusts better to the measured data than the Batchelor model, and the values of the turbulent parameter that better fit the experimental data are qB = 4.4 ± 0.8 and qK = 7.9 ± 2.5 for Batchelor and Kraichnan, respectively, when Cox ≥ 50. Once the turbulent parameter is fixed, a comparison of the value of ɛ determined from fitting the thermal gradient spectra to the value obtained after fitting the shear spectra shows that the Kraichnan model gives a very good estimate of the dissipation, which the Batchelor model underestimates.

On turbulent separation in the flow past a bluff body

1992 ◽  
Vol 241 ◽  
pp. 443-467 ◽  
Author(s):  
A. Neish ◽  
F. T. Smith
Keyword(s):  
Large Scale ◽  
Bluff Body ◽  
Separated Flow ◽  
Small Scale ◽  
Supporting Evidence ◽  
Turbulent Regime ◽  
Trailing Edge ◽  
Flow Past ◽  
Starting Point ◽  
Turbulence Factor

The basic model problem of separation as predicted by the time-mean boundary-layer equations is studied, with the Cebeci-Smith model for turbulent stresses. The changes between laminar and turbulent flow are investigated by means of a turbulence ‘factor’ which increases from zero for laminar flow to unity for the fully turbulent regime. With an attached-flow starting point, a small increase in the turbulence factor above zero is found to drive the separation singularity towards the trailing edge or rear stagnation point for flow past a circular cylinder, according to both computations and analysis. A separated-flow starting point is found to produce analogous behaviour for the separation point. These findings lead to the suggestion that large-scale separation need not occur at all in the fully turbulent regime at sufficiently high Reynolds number; instead, separation is of small scale, confined near the trailing edge. Comments on the generality of this suggestion are presented, along with some supporting evidence from other computations. Further, the small scale involved theoretically has values which seem reasonable in practical terms.

With Different Axial Compression, the Finite Element Analysis of Concrete Frame Column that Reinforced by Assemble Inclined Web Steel Truss

2014 ◽  
Vol 1079-1080 ◽  
pp. 177-182
Author(s):  
Shao Wu Zhang ◽  
Ying Chuan Chen ◽  
Geng Biao Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Simulation Analysis ◽  
Hysteresis Curve ◽  
Element Analysis ◽  
Concrete Frame ◽  
The Finite Element Analysis ◽  
Steel Truss

In order to study the performance of concrete frame columns that reinforcedby assembleinclined web steel truss, with the same reciprocatinghorizontal displacement and different axialcompression.It canbe calculate the mechanical behavior of concrete frame columns and reinforced columns by using the finite element analysis software ABAQUS. Simulation analysis shows that the bearing capacity ofreinforced columnshas greatly increased andpresented a full hysteresis curve. The result shows that the reinforcement method of assemble inclined web steel truss can greatly improve the bearing capacity and ductility of the concrete frame column, and the axial compression is larger, the better the reinforcement effect.

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