Dissertation
Dissertation > Transportation > Road transport > Bridges and Culverts > Structural principles, structural mechanics

Experimental Research on Static and Dynamic Responses of Bridge Longitudinal Truss with Typical Welded Details

Author YinAiGuo
Tutor LiZhaoXia;HuangYuePing
School Southeast University
Course Solid Mechanics
Keywords Steel truss structure Welding details Scale model experiments Structural simulation Pseudo-dynamic experimental system Stress concentration
CLC U441
Type Master's thesis
Year 2006
Downloads 229
Quotes 9
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The structure of local damage and fatigue accumulated is the main reason for the failure of the structure, and therefore the state must accurately assess the finite element simulation of the bridge structure analysis of the dynamic response of the structure under actual service loads and critical welding details at the hot spot stress distribution. Modeling theory is still difficult to consider the fact the presence of local defects in the structure and evolution of the damage process simulation analysis. Therefore, consider the the local welding details characteristics of the structure simulation of academic importance for the analysis of structural damage. The main content of this article is the law from the point of view of the experimental study to investigate the static and dynamic response of bridge steel truss structure with local welding details. The experimental research is an effective means of understanding and analysis of complex structural system stress distribution law and dynamic characteristics parameters, test information can be obtained by the experimental study provide experimental support for the finite element simulation study of the structure of the local welding details. This study by the National Natural Science Foundation project \1:5 scale model of the experimental study Tsing Ma Bridge in Hong Kong longitudinal stiffening trusses standard segment (4.2m × 1.32m, a total of bay) as a representative of the steel truss structure with local welding details, various conditions of static Dynamic load response of experimental studies; focused on the the welding area near the strain stress distribution law, the the hotspot stress distribution and stress concentration factor discussed. For the purpose and content of the experimental study, the completion of a scale model of the steel truss structure developed and experimental program of study; tested on the material properties of the sample structure as a whole and the local welding details at the base metal, weld toe near material performance parameters of the three parts of the area and welding consumables (weld heap); according to the experimental program, based on existing laboratory equipment and part of the self-developed equipment complete with local welding details the steel trusses scale model static and dynamic load experimental the original modal parameters of the experimental model, the nodal displacement and rotation angle and overall points and three local strain of the survey area information; static and dynamic test set out in response to the information from the overall stress distribution, the distribution and the impact of the local stress factors, and other aspects of the analysis, global and local stress distribution law, as well as the hot zone of stress concentration factor changes with changes in boundary conditions, load cases, such as trends. The experimental results of the study show that: 1) containing the the local welding details sample of material performance parameters must be three types of values, base metal, weld toe area and welding consumables (weld heap), due to the local weld , by the material properties of the changed parameters, and not simply to take a value to each alternative. 2) the entire truss force characteristics of the sample is close to the beam-type structure as the main form in the boundary constraint and loading conditions, the samples of the overall model is applied to flexural, specific to the performance of the various parts of the lever member: truss structure upper and lower chords than other rod force uniform the mainly axial stress; the central abdominal lever smaller force, except both ends diagonals axial stress, both ends of the diagonals of the structural model of stress The amplitude of the largest part of the highest stress levels. 3) With the constraint strengthen, the stress distribution of the entire truss structure relatively more flatten the overall stress level will be reduced. 4) local stress distribution of the survey area with the hot zone of stress concentration phenomenon not only around the weld details, but also by the load in the form of the model structure, related to the conditions set out the Infliction position load from the experimental results, the same under the condition of uniform load caused by stress concentration is smaller than the concentrated load slows down as the load increases the rate of increase of the stress concentration factor; shading weld form of the experimental structure is complex, criss-crossing, non-linear stress concentration factor Variation. 5) the stress distribution law of the static and dynamic load caused the structure is basically the same, the amplitude appears consistent position, but different points of the relative sensitivity of different static load or dynamic load, which primarily related to the measuring point location and load cases. Dynamic strain testing

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