| The steel box girder-tree-shaped steel column pillar pedestrian landscape bridge has many advantages such as beautiful shape and reasonable stress.It is more and more used in ecological park attractions.However,the current research on steel box girder-tree-shaped steel column pillar pedestrian landscape bridge is still insufficient,and the study of its mechanical properties is of great significance to its popularization and application.According to the stress characteristics of the steel box girder-tree-shaped steel tube column pier pedestrian landscape bridge,this study uses the isolation method,which is divided into two research objects: bridge span structure and tree-shaped steel tube column pier.When studying the mechanical properties of the bridge span structure,the effect of the tree-shaped steel pipe column piers on the bridge span structure can be simplified as the restraining effect of the branch branch steel pipe on the bridge span structure;The characteristics of the reaction force are analyzed,and the loading characteristics of the tree-shaped steel tube pier are reversed according to the principles of the acting force and the reaction force,so as to determine the loading scheme.Research on bridge span structure: This paper combines the software Midas FEA to study the influence of central angle,height difference and span on the dynamic characteristics,vertical acceleration,von Mises stress and deflection of bridge span structure and other mechanical indicators.Then based on the principle that the error of the simplified model is not more than 5%,a reasonable simplified scheme for the calculation model of the bridge span structure is proposed.Finally,taking a pedestrian landscape bridge in Kuitun,Xinjiang as an example,the reliability of the simplified scheme of the bridge span structure calculation model was verified.Through analysis,the following conclusions can be obtained:(1)The maximum vertical acceleration of the bridge span structure is not obtained when the first-order vertical natural vibration frequency of the bridge span structure is equal to the pedestrian excitation load frequency.In addition,the comfort of the bridge span structure cannot meet the specifications,and vibration damping measures need to be taken.(2)Under constant live load,the von Mises stress of the bridge structure increases exponentially with the increase of the span;under temperature load,the von Mises stress of the bridge structure gradually increases and changes with the increase of the span The amplitude is smaller.(3)When ignoring the height difference(slope i?14.28%)of the calculation model of the bridge span structure,the errors caused by various mechanical indexes are less than 5%.Therefore,when the bridge span structure(slope i?14.28%)is used for structural design,the calculation model can be directly simplified without considering the height difference.(4)When the center angle is not greater than 45 °,when the calculation model of the bridge span structure is simplified to ignore the center angle,the error of each mechanical index is less than 5%,and the calculation model can be directly simplified to ignore the center angle and substitute the straight curve.When the center angle is greater than 45 °,the error caused by the straight-line simplification of the calculation model is greater than 5%,and the straight-line simplification cannot be used directly.Study on the mechanical properties of tree-shaped steel tube column piers: This paper combines the finite element software ABAQUS to analyze the presence and absence of filled concrete and the strength grade of the filled concrete and the thickness of the steel tube wall on the tree-shaped steel tube column piers under axial load,The impact of carrying capacity.Through analysis,the following conclusions can be obtained:(1)Under axial compression and lateral thrust loads,the yielding area of the tree-shaped steel tube pier first appears at the steel tube node and the root of the main trunk.(2)After the concrete-filled steel tubes of the tree-shaped steel column pier are filled with concrete,their axial compression bearing capacity and lateral displacement bearing capacity have been greatly improved,of which the axial compression bearing capacity has been more obviously improved.(3)As the strength level of the filled concrete increases,the bearing capacity of the tree-shaped steel tube pier increases less.(4)Regardless of factors such as the presence or absence of filled concrete and the strength grade of filled concrete,the bearing capacity of tree-shaped steel tube pier increases linearly with the increase of the thickness of the steel tube wall.(5)As the wall thickness of the steel tube increases and the strength level of the filled concrete increases,the increase in the bearing capacity of the concrete filled with tree-shaped steel tube pier decreases. |
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