Parameter Analysis on High-Pier's Effective Length Factor of Fabricated Beam Bridge

2013 ◽  
Vol 361-363 ◽  
pp. 1272-1277
Author(s):  
Peng Liu ◽  
Yong Jun Li ◽  
Fei Zheng ◽  
Jie Rui
Keyword(s):  
Critical Force ◽  
Parameter Analysis ◽  
Effective Length ◽  
Ideal Boundary ◽  
Dead Weight ◽  
First Order ◽  
Effective Length Factor ◽  
High Pier ◽  
The Stability ◽  
Beam Bridge

This paper illustrates the calculation method of effective length factor of the high-pier of fabricated beam bridge on the basis of Eulers formula by obtaining the critical force of first-order buckling according to the stability analysis. Engineering example is applied to calculate the effective length factor in the construction stage of fabricated beam bridge. Further, parameter analysis is used to study the variation of effective length factor and the influence of dead weight, non-ideal boundary conditions, the height and the radius of high-pier on it is evaluated. Results show that: there are many influencing factors acting on the effective length factor which cannot simply be represented by a fixed value and the calculation of the effective length factor should depend on the specific conditions of high-piers.

A Calculation Method of High-Pier's Effective Length Factor Considering the Dead Weight

2013 ◽  
Vol 361-363 ◽  
pp. 1278-1283
Author(s):  
Peng Liu ◽  
Rui Zhi Wang ◽  
Fei Zheng ◽  
Qiong He
Keyword(s):  
Boundary Conditions ◽  
Calculation Method ◽  
Critical Force ◽  
Effective Length ◽  
Ideal Boundary ◽  
Dead Weight ◽  
Numerical Examples ◽  
First Order ◽  
Effective Length Factor ◽  
High Pier

Nowadays, uncertainty regarding the calculation method of effective length factor of high-pier has brought many inconveniences to the design of bridge. To solve the problem, this paper demonstrates the calculation method of effective length factor on the basis of Eulers formula considering both the influence of high-pier s dead weight and non-ideal boundary conditions on the critical force of first-order buckling. The influence of piers dead weight on effective length factor in the construction and finished stage are evaluated by numerical examples. Results show that: the effective length factor becomes smaller considering dead weight both in construction and finished stage. Moreover, high-piers dead weight causes more influence in the construction stage than finished stage which should be considered seriously in the design and construction.

Energy Method for the Calculation of High-Pier's Effective Length Factor at the Finished Stage

2013 ◽  
Vol 361-363 ◽  
pp. 1115-1118
Author(s):  
Peng Liu ◽  
Jie Rui ◽  
Bo Lei ◽  
Fei Zheng
Keyword(s):  
Boundary Conditions ◽  
Energy Method ◽  
Good Accuracy ◽  
Shape Function ◽  
Great Influence ◽  
Effective Length ◽  
Ideal Boundary ◽  
Effective Length Factor ◽  
High Pier ◽  
The One

This paper establishes the shape function of high-pier with non-ideal boundary conditions in the top and uses the energy method to calculate its critical load. Then its effective length factor is achieved by using Euler's formula. Further, the FEM and energy method are respect used to calculate the effective length factor of the engineering example and comparative analysis is carried on. Results show that: The non-ideal boundary conditions have great influence on the effective length factor and should be considered in the calculation. The result from the formula of energy method is nearly the same as the one from the FEM which demonstrates this method is of good accuracy to calculate the effective length factor of high-pier. In addition, it is also of great convenience in the design of high-piers.

scholarly journals COMPARATIVE ANALYSIS OF THE BUCKLING FACTOR OF THE STEEL ARCH BRIDGES

2019 ◽  
Vol 11 (1) ◽  
pp. 11-16
Author(s):  
Sigutė Žilėnaitė
Keyword(s):  
Comparative Analysis ◽  
20Th Century ◽  
Compressive Force ◽  
Critical Force ◽  
Effective Length ◽  
Initial Stresses ◽  
Axial Compressive Force ◽  
Late 20Th Century ◽  
Arch Bridges ◽  
The Stability

The dominant axial compressive force makes the arches become extremely sensitive to the loss of stability. Their stability analysis was first initiated in the late 20th century. The first stability research of single arches was carried out inplane at the elastic stage of the arches. Later the behaviour of arches in the elastic-plastic stage, the initial stresses and geometric imperfections before the arch buckles were also assessed, the effective length of the arches and the out-of-the-plane arch strength conditions were being identified as well as the effect of the temperature on the stability of the arch. The expression of the critical force of the arches connected by vertical hangers with a chord and its dependant elements were defined by Petersen in the late 20th century. The design methodology for the formal design of arches connected by vertical hangers with a stiffening girder is presented in Annex D of the Eurocode 1993-2. Nevertheless, the area of application and the main assumptions are not defined. The first part of the comparative analysis identifies the assumptions for arch bridge modelling under which the buckling factor β dependence curves in Figure D.4 of Annex D to Eurocode 1993-2 can be applied. In the second part a comparison of the the normative βEC factor value and the one established by the numerical experiment with the increase in the number of hangers and change in the hanger network form is presented.

Pier Form Selection and Parameter Analysis of Reinforced Concrete Thin-Wall High Pier

2012 ◽  
Vol 463-464 ◽  
pp. 239-243
Author(s):  
Xiao Mei Dong ◽  
Yan Wen
Keyword(s):  
Reinforced Concrete ◽  
Internal Force ◽  
Parameter Analysis ◽  
Thin Wall ◽  
Force Analysis ◽  
Nonlinear Stability Analysis ◽  
Long Span ◽  
Rigid Frame ◽  
High Pier ◽  
The Stability

Two forms of reinforced concrete pier were compared by internal force analysis and nonlinear stability analysis. According to the restriction of the stability and intensity, size optimization of the high piers’ section is calculated by means of differential coefficient. The results of the calculation and analysis indicate that the parameter optimization of the piers’ section of Long-span continuous rigid frame bridges is feasible by using the optimization model, and the results are provided to the optional design of Long-span continuous rigid frame bridges.

scholarly journals An accurate method for the calculation of ultimate load in lattice boom

2019 ◽  
Vol 11 (11) ◽  
pp. 168781401988677 ◽  
Author(s):  
Liming Zhou ◽  
Jinghao Tang ◽  
Weijie Wang ◽  
Erfei Zhao ◽  
Shuhui Ren ◽  
...  
Keyword(s):  
High Strength Steel ◽  
Ultimate Load ◽  
Design Method ◽  
High Strength ◽  
Accurate Method ◽  
Effective Length ◽  
Stability Factor ◽  
Steel Tubes ◽  
Effective Length Factor ◽  
The Stability

To calculate the ultimate load of the lattice boom accurately, the effective length factor and imperfection factor are introduced to the current stability factor formula. First, we propose a stability factor formula by conducting a series of tests of high-strength steel tubes under axial compression and analyzing the experimental data. Second, the effective length factor of the chord which is caused by braces is calculated on the basis of different effective length factors and stability curves. Then, the correctness of the proposed effective length factor and the stability factor formula are proved by destructive tests under three loading modes. Using the modified stability factor formula, the accuracy of ultimate load of lattice boom is enhanced. These findings will be of great value for improving the design level of lattice boom and providing a theory and test basis for the completion of the buckling design method of the high-strength steel tubes.

scholarly journals Bleaching of chlorophylls by UV irradiation in vitro: The effects on chlorophyll organization in acetone and n-hexane

2008 ◽  
Vol 73 (3) ◽  
pp. 271-282 ◽  
Author(s):  
Jelena Zvezdanovic ◽  
Dejan Markovic
Keyword(s):  
Uv Irradiation ◽  
Photosynthetic Pigments ◽  
Energy Input ◽  
First Order ◽  
First Order Kinetics ◽  
Uv Photons ◽  
The Stability ◽  
Major Factors

The stability of chlorophylls toward UV irradiation was studied by Vis spectrophotometry in extracts containing mixtures of photosynthetic pigments in acetone and n-hexane. The chlorophylls underwent destruction (bleaching) obeying first-order kinetics. The bleaching was governed by three major factors: the energy input of the UV photons, the concentration of the chlorophylls and the polarity of the solvent, implying different molecular organizations of the chlorophylls in the two solvents.

scholarly journals On Minimum-B Stabilization of Electrostatic Drift Instabilities

1966 ◽  
Vol 21 (11) ◽  
pp. 1953-1959 ◽  
Author(s):  
R. Saison ◽  
H. K. Wimmel
Keyword(s):  
Dispersion Relation ◽  
Particle Distribution ◽  
Inhomogeneous Plasma ◽  
Distribution Functions ◽  
Loss Cone ◽  
First Order ◽  
Stabilization Theorem ◽  
The Stability ◽  
Necessary And Sufficient ◽  
Limiting Case

A check is made of a stabilization theorem of ROSENBLUTH and KRALL (Phys. Fluids 8, 1004 [1965]) according to which an inhomogeneous plasma in a minimum-B field (β ≪ 1) should be stable with respect to electrostatic drift instabilities when the particle distribution functions satisfy a condition given by TAYLOR, i. e. when f0 = f(W, μ) and ∂f/∂W < 0 Although the dispersion relation of ROSENBLUTH and KRALL is confirmed to first order in the gyroradii and in ε ≡ d ln B/dx z the stabilization theorem is refuted, as also is the validity of the stability criterion used by ROSEN-BLUTH and KRALL, ⟨j·E⟩ ≧ 0 for all real ω. In the case ωpi ≫ | Ωi | equilibria are given which satisfy the condition of TAYLOR and are nevertheless unstable. For instability it is necessary to have a non-monotonic ν ⊥ distribution; the instabilities involved are thus loss-cone unstable drift waves. In the spatially homogeneous limiting case the instability persists as a pure loss cone instability with Re[ω] =0. A necessary and sufficient condition for stability is D (ω =∞, k,…) ≦ k2 for all k, the dispersion relation being written in the form D (ω, k, K,...) = k2+K2. In the case ωpi ≪ | Ωi | adherence to the condition given by TAYLOR guarantees stability.

scholarly journals Effects of heat treatment and storage temperature on the use of açaí drink by nutraceutical and beverage industries

2012 ◽  
Vol 32 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Tatiane Regina Albarici ◽  
José Dalton Cruz Pessoa
Keyword(s):  
Temperature Effect ◽  
Storage Temperature ◽  
Life Time ◽  
Reaction Rate Constant ◽  
Anthocyanin Content ◽  
Order Kinetic ◽  
First Order ◽  
The Stability ◽  
And Storage ◽  
Anthocyanin Degradation

This study assesses the storage temperature effect on the anthocyanins of pasteurized and unpasteurized açaí pulp. The data was obtained using a pasteurized and lyophilized pulp (PLP) to evaluate the temperature effect (0, 25, and 40 °C). Part of non-pasteurized frozen pulp (NPP) was pasteurized (NPP-P) at 90 °C for 30 seconds; both pulps were stored at 40 °C. The anthocyanin content reduction in the drink was evaluated from the half-life time (t1/2), activation energy (Ea), temperature quotient (Q10), and the reaction rate constant (k). The t1/2 of the PLP anthocyanins stored at 40 °C was 1.8 times less than that stored at 25 °C and 15 times less than that stored at 0 °C; therefore, the higher temperatures decreased the stability of anthocyanins. The pasteurization increased the t1/2 by 6.6 times (10.14 hours for NPP and 67.28 hours for NPP-P). The anthocyanin degradation on NPP-P followed a first order kinetic, while NPP followed a second order kinetic; thus it can be said that the pasteurization process can improve the preservation of anthocyanins in the pulp.

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: II. THE DECOMPOSITION OF THE ISOMERIC ESTERS BUTYLIDENE DIACETATE AND ETHYLIDENE DIPROPIONATE

1932 ◽  
Vol 6 (4) ◽  
pp. 417-427 ◽  
Author(s):  
C. C. Coffin
Keyword(s):  
Activation Energy ◽  
Degrees Of Freedom ◽  
Maximum Energy ◽  
Velocity Measurements ◽  
First Order ◽  
Gas Reactions ◽  
Points Of View ◽  
The Stability ◽  
Future Work ◽  
Internal Degrees Of Freedom

The gaseous decompositions of the esters butylidene diacetate and ethylidene dipropionate have been studied from points of view previously outlined in papers on the decomposition of ethylidene diacetate (2, 3). The decomposition velocities have been measured at initial pressures of from 5 to 56 cm. of mercury and at temperatures between 211 and 265 °C. The reactions are homogeneous and of the first order. They agree with the Arrhenius equation and give 100% yields (within experimental error) of an aldehyde and an anhydride. The preparation of the compounds and improvements in the technique of the velocity measurements are described.While the specific velocities of the three reactions at any temperature are somewhat different, their activation energies are the same. It is suggested that in the case of such simple reactions, which are strictly localized within the molecular structure, the activation energy can be identified as the maximum energy that the reactive bonds may possess and still exist; i.e., it may be taken as a measure of the stability of the bonds which are broken in the reaction. The suggestion is also made that for a series of reactions which have the same activation energy, the specific velocities can be taken as a relative measure of the number of internal degrees of freedom that contribute to the energy of activation. On the basis of these assumptions it becomes possible to use reaction-velocity measurements for the investigation of intramolecular energy exchange. The theoretical significance of the data is further discussed and the scope of future work in this connection is indicated.The monomolecular velocity constants (sec−1) of the decomposition of ethylidene diacetate, ethylidene dipropionate and butylidene diacetate are given respectively by the equations [Formula: see text], [Formula: see text], and [Formula: see text].

scholarly journals On the stability of first order impulsive evolution equations

2014 ◽  
Vol 34 (3) ◽  
pp. 639 ◽  
Author(s):  
JinRong Wang ◽  
Michal Fečkan ◽  
Yong Zhou
Keyword(s):  
Evolution Equations ◽  
First Order ◽  
The Stability ◽  
Impulsive Evolution Equations
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