Research On Out-of-plane Stability Of Steel Arch For H Section

Arches are widely used in bridge engineering and structure engineering for their beautiful shape, large rigidity and good economic gains, etc. However, the lateral and torsional stiffness is limited, the stability problem always exists, especially, the out-of-plane stiffness of arch rib is far smaller than in-plane stiffness of that, the out-of-plane stability problem is more serious.Stability problem generally is divided into two sorts, the first type comes down to evaluate eigenvalue problem, which is easy to be calculated. due to the effect of the material nonlinear, geometry nonlinear and original bug, the second kind stability is ultimate load carrying capacity problem ,which is more reasonable comparing to the true result. the existing theory is my paper' s guidance.Firstly, this thesis discusses the stability of arch from analytic approach, and theoretical formulas for out-of-plane elasticitical stability of circular arch are deduced, obtains arch total potential energy equation of out-of-plane stability. Secondly,The finite element methods to analyse stability are summarized, including the nonlinearity theory, and the ways and means to solve nonlinear stability are presented;the criterions to judge buckling and estimate stability are refered; the techniques to analyse stability in ANSYS are introduced.Elastic lateral stability capability is studied. The buckling loads of arch with different load condition ,subtended angle, support restraint, lateral bracing is derived by using the finite elements method. Obtains the buckling loads along with the center of circle angle to increase reduces gradually. the paper analyze the condition of lateral bracing than the other conditions. the paper also use the later bracing to keep the steel arches structure overall stability, this is because without lateral bracing the arch of buckling loads is very small. In the actual engingeering of no significance, lateral bracing shoule be provided to raise their buckling loads. and analyze the relations of the number of the lateral bracing and overall stability. When there is a lateral bracing in arch rib and central angle greater than 60°,To simplify analysis, the two hinged arch of the no lateral bracing can be used to be replace the arch rib between lateral bracing points and bearing. In the design, when with lateral bracing the bearing set to hinge bearings. this is not only on the impact of smaller buckling loads, but also the hinge for the construction of the bearing structure requirements easier to achieve.