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Dou C.,Beijing Jiaotong University | Dou C.,Beijings Key Laboratory of Structural Wind Engineering and Urban Wind Environment | Pi Y.-L.,University of New South Wales
Journal of Structural Engineering (United States) | Year: 2016

This paper presents the flexural-torsional buckling resistance and design of steel circular arches subjected to uniform compression with elastic end bending restraints by using finite element (FE) numerical analyses. Firstly, effects of geometric and mechanical parameters such as initial imperfections, section types, material properties, slenderness, rise-to-span ratios, and end restraints on flexural-torsional buckling resistances of arches are investigated and are found to be eliminated to a large extent by introducing the normalized slenderness. Then, on the basis of extensive numerical results, a design method is proposed to predict the flexural-torsional buckling resistances of circular arches in uniform compression with elastic end restraints by the column curves according to the normalized slenderness and a specific section type, namely curve 'a' for hollow sections, curve 'b' for welded box sections, and curve 'c' for welded I-sections. Next, the flexural stiffness of an arch is studied, taking the destabilizing effect of the axial force into account to calculate the end restraining provided by adjacent arch segments to the adverse segment in a laterally-braced arch in uniform compression to obtain the flexural-torsional buckling resistance using the normalized slenderness and the column curve analytically. The result shows a good agreement with that gained from finite element numerical analyses, and proves it very conservative when the adverse segment is assumed to be hinged without any end restraining. © 2015 American Society of Civil Engineers. Source


Dou C.,Beijing Jiaotong University | Dou C.,Beijings Key Laboratory of Structural Wind Engineering and Urban Wind Environment | Jiang Z.-Q.,Beijing University of Technology | Pi Y.-L.,University of New South Wales | Guo Y.-L.,Tsinghua University
Engineering Structures | Year: 2016

This paper deals with elastic shear buckling behavior of infill panels in sinusoidally corrugated steel plate shear walls, and fitting equations predicting the shear buckling loads are presented. Firstly by using finite element analyses (FEA), the previous formulae for bending rigidities of sinusoidally corrugated plates are revised, then pure shearing model are established to study the effects of key parameters on elastic shear buckling of sinusoidally corrugated infill panels, such as the aspect ratio, corrugation ratio, corrugation depth to plate thickness ratio and corrugation repeating number. Based on extensive FEA numerical results, fitting equations with good accuracy are proposed to estimate elastic shear buckling loads of sinusoidally corrugated panels, which are improved much compared with the solutions in previous studies. It is found that, the formulae for bending rigidities of corrugated plates revised in this paper are accurate compared with the previous ones. For sinusoidal corrugated infill panels, only global buckling and local buckling can be observed in the lowest buckling mode of eigenbuckling analysis, while interaction buckling is not obvious. The parameter of corrugation repeating number has a significant influence on elastic shear buckling loads, whereas it was neglected in previous studies. © 2016 Elsevier Ltd. Source


Liu P.,Beijing Jiaotong University | Liu P.,Beijings Key Laboratory of Structural Wind Engineering and Urban Wind Environment
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2015

An approach based on Bayesian theorem and structural vibration test data was presented for reliability updating. The approach takes account of uncertainties of the excitation, structural model and its parameters. Structural model parameters were identified based on the vibration test data and Bayesian parameter identification. According to Laplace asymptotic approximation, the dynamic reliability estimated purely in the light of design conditions was updated. The reliabilities of a truss structure subjected to dynamic random loading were calculated for three cases. Only the uncertainty of the loading was considered for the first case. The uncertainties of the loading and the prior probability distribution of model parameters were considered for the second case. The uncertainties of the loading and the updated probability distribution of model parameters were considered for the third case. Natural frequencies and mode shapes of the actual structure and the updated model were compared. Discussions about the updated reliabilities were made. The results show that the updated failure probability of the tested DOF agrees better with the actual value compared with that by deterministic nominal models. The updated failure probability of untested DOFs may deviate from the actual values. Increasing tested DOFs may have no effect on the updated failure probability. ©, 2015, Chinese Vibration Engineering Society. All right reserved. Source


Liu P.,Beijing Jiaotong University | Liu P.,Beijings Key Laboratory of Structural Wind Engineering and Urban Wind Environment | Lian P.-Y.,Beijing Jiaotong University
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2016

Ambient vibration tests of a frame structure consisting of the main building and podium without seismic joint were conducted and the dynamic characteristics of the structure were analyzed. The sensors employed in the tests were mounted on the right and left stairwells, the fourth floor of the main building and the large span floor of the podium with grillage beams. With the measured acceleration data and by using an improved frequency domain decomposition method, the modal parameters of five modes were identified. Consistent identification results were obtained by different test schemes. The fluctuation of identified natural frequencies is smaller than that of damping ratios. The first four modes are induced by the vibration of the main building. The fifth mode is the first vertical bending mode of the podium. The torsional behavior appears in the first three modes due to the asymmetry of the structure. The spurious modes during identification may be due to the dynamic interactions between the main building and podium. A finite element model of the tested structure was constructed and five modes were obtained, which agree well with the identification results. The influence of different connection forms between the main building and podium on the natural frequencies and mode shapes of the structure were analyzed. Results show that fixed or pinned connections between the main building and podium have almost no influence, while presence of seismic joint has large influence on the natural frequencies of the structure. The order of the mode shapes does not change for all the cases. © 2016, Chinese Vibration Engineering Society. All right reserved. Source


Li B.,Beijing Jiaotong University | Li B.,Beijings Key Laboratory of Structural Wind Engineering and Urban Wind Environment | Zhang J.,Beijing Jiaotong University | Yang Q.-S.,Beijing Jiaotong University | Yang Q.-S.,Beijings Key Laboratory of Structural Wind Engineering and Urban Wind Environment
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2016

Wind tunnel velocity tests have been carried out to investigate the windbreak performance of wind barriers on bridges considering different barrier porosities and widths, the wind barrier wind tunnel simulation method and evaluation parameter of windbreak performances are discussed in the paper. Test results show that the shielding region of wind barriers is about 2.0 H (H is the height of wind barrier) and that wind speed decreases significantly when the height is below 1.0 H. The turbulence intensity of the downstream flow on the wind barrier reaches the maximum at a height of 1.0 H. Windbreak performance depends on porosity of wind barrier, wind speed will rise and turbulence intensity decreases with increasing porosity. Barrier width seems to have no relationship with windbreak performance; when porosity is the same, the effect of barrier width can be ignored. The wind speed reduction coefficient can be used to evaluate windbreak performance, which is defined by pressure equivalence. © 2016, Editorial Office of Journal of Vibration and Shock. All right reserved. Source

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