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Research on Time-Varying Reliability of Suspension Bridge Hanger in a Whole-Life Period

Author: YangZuo
Tutor: ShaoXuDong
School: Hunan University
Course: Bridge and Tunnel Engineering
Keywords: Suspension Bridge Slings Resistance to degradation Corrosion Dynamic Reliability Fluctuating wind buffeting force Fatigue reliable indicator LCCA
CLC: U443.38
Type: Master's thesis
Year: 2009
Downloads: 272
Quote: 0
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Abstract

In recent years, with the rapid development of China's transport undertakings, the construction of many large span, King-span bridge across the canyon, Strait land-island and large rivers. Suspension bridge spanning capacity sling as the suspension bridge's main power transmission components, the use of the environment is poor and vulnerable to the surrounding atmosphere, the effect of temperature and deterioration, and long-term affordable car wind dynamic load, easily lead to fatigue problems. More than the cable system bridges due to various reasons and have been forced to change cable, it will affect the use of the bridge and caused huge economic losses. To Aizhai bridge engineering background, sling suspension bridge in the lifetime of reliable indicators of change, carried out the research work of the following aspects: (1) analysis of the reasons for the suspension bridge the sling resistance degradation, including slings protection system damaged and sling wire resistance degradation mechanism. Climate according to the Aizhai bridge location at the environment and corrosive media to explore the mechanism of corrosion in acid rain environment and corrosion damage morphology compared the impact of pitting and uniform corrosion in two different corrosion model, results showed that the corrosion initial , the widening gap between growth over time, the late grown over time both gradually close. (2) asymmetry for Aizhai bridge structure, according to the Segmental catenary method, preparation of the XLX.FOR procedures, and ANSYS mixed calculated get into bridge state. (3) Summary of the bridge structure reliability theory, focus on comparing the merits of different methods of solving. Using response surface binding JC method to calculate the sling Aizhai bridge over the lifetime of static, dynamic and reliable indicators, the results show that when the impact of corrosion consider only the cross-sectional area decreases, the sling has been in a safer state. Sensitivity analysis of some parameters, indicating that the sling cross-sectional area of ??the variability of the reliable indicators. (4) of the bridge Aizhai fluctuating wind buffeting vibration force under stress time calculated by rainflow counting procedure statistics stress amplitude fatigue reliability analysis Aizhai bridge slings. The calculation results show that the fatigue reliability index is basically reduced with the shortened length of the sling, cross-the short sling fatigue in reliable indicators of only 3.062. According to the slings degradation in the lifetime of the law, considering the fatigue a reliable indicator of changes in life expectancy during the period fitting a fatigue reliable indicators consider the time and sling length formula. (5) preliminary design of improvements made the Aizhai bridge slings structure, increased fatigue reliable indicator of the sling, and contrast with the original design of the full life cycle cost. The sling system in the whole life of the examination, conservation and replacement sling and sling structure preservation of new materials and new technology development.

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