Static And Stability Analysis Of A Long-span Double-arch-support Steel Structure

Since the virtues of the good compression performance of the arch and lightweight steelmaterial, steel arch structure has a large span and can reduce the stress level under gravityload efficiently and horizon thrust force in column footing greatly. A long-spandouble-arch-support steel structure this thesis studies is combined with the upper tube archand lower space truss-arch. The upper tube arch is ensured its out-of-plane stability bylimitation of spacing cable. Considering static and stability analysis of this new structuresystem is not abundant in recent years, the resrarch work of this thesis appears to besignificant.Firstly, this thesis formulates the nonlinear finite element theory of the long-spandouble-arch-support steel structure, including geometric nonlinear analysis, material nonlinearanalysis, solution methods of nonlinear finite element problem and so on.Secondly, in this thesis, two types of arch structures which are single arch structure anddouble-arch-support structure are selected for detail to investigation. Nonlinear static analysisis given as well as similarities and differences of these two types of strcutures’ static behaviorin terms of internal force, deformation and support reation in arch foot of the arch. Moreover,this thesis also researches vertical load share ratio of the upper and the lower arch underdifferent load cases and change rules of arch’mechanical properties under different loadcombinations. According to the calculation results, it is insecure to adopt the simplified modelof omitting the lower concrete stand structure. So this simplified model is not proposed to usein the engineering pratice.Thirdly, this thesis introduces two examples of single arch structure anddouble-arch-support structure, providing the stability problem and the research method ofsteel structure. Compareing single arch structure, elastic stability capacity ofdouble-arch-support structure increases while deformation and initial imperfection sensitivityreduce. After that, this thesis studies stability behavior, deformation performance andimperfection sensitivity of the double-arch-support structure under uniform load for differentparameters. Analysis results indicate that the parameters this thesis chooses is reasonable. Ifsimplified model of omitting the lower concrete stand structure made application forengineering practice, it is better to establish a reduction factor for ensuring accuracy of theresults. In the end of the thesis, based on the assumption that teel structure material iselastic-perfectly plastic material while cable is perfectly elastic material, elastic-plasticstability behavior of single arch structure and double-arch-support structure is analyzed. Itshows that stable ultimately bearing capability of structure reduces obviously when doublenonlinear taken into account. Finally, this thesis studies stability behavior and imperfectionsensitivity of the double-arch-support structure under uniform load for different parameters indetail. The conclusions of this thesis is valuable for similar engineering.