大跨度多塔悬索桥主缆服役安全性评估方法研究

Large-span multi-tower suspension bridge is widely used in the construction of bridges across the river and sea. The loading bearing and anti-skidding safeties of its main cable directly affect the safety of suspension bridge structure. The main cable of large-span multi-tower suspension bridge is chosen as the research object in this project. Firstly, effects of temperature, wind parameters and design parameters of the suspension bridge on the dynamic load, vibration states and tribo-fatigue damage parameters of the main cable at the main cable saddle under the coupled vibration of wind, traffic loads and bridge system will be studied. Secondly, evolution models of internal and external tribo-corrosion-fatigue damages of the main cable under coupled effects of temperature and electrochemical corrosion. Afterwards, we will reveal dynamic contact and micro-slip mechanisms between the main cable and the main cable saddle under coupled roles of temperature, electrochemical corrosion and dynamic load. Therefore, the model of loading bearing safety factor attributed to tribo-corrosion-fatigue damage will be proposed, and the safety factor model of anti-skidding between the main cable and the main cable saddle under coupled roles of temperature, electrochemical corrosion and dynamic load will be established. Thereafter, the correlations between loading bearing safety factor, and design parameters of the suspension bridge and environmental parameters (temperature, wind and electrochemical corrosion medium), will be established, respectively. Meanwhile, the correlations between the anti-skidding safety factor, and suspension bridge design parameters and environmental parameters, will be obtained, respectively. Thus, main factors affecting the service safety of the main cable will be determined. Finally, optimum design parameters of the suspension bridge improving the service safety of main cable will be proposed. Research results are of important theoretical significance to improving the service safety of the main cable and to ensuring the safety of the large-span multi-tower suspension bridge.

大跨度多塔悬索桥广泛应用于跨江、跨海桥梁建设，其主缆承载安全性和抗滑安全性直接关系到悬索桥结构安全性。本项目将以大跨度多塔悬索桥主缆为研究对象，研究风-车-桥梁系统耦合振动工况下温度、风参数和悬索桥设计参数对主缆时变动载荷、振动状态和摩擦疲劳损伤参数的影响规律，建立温度和电化学腐蚀效应下主缆内、外部摩擦腐蚀疲劳损伤演化模型，揭示温度-电化学腐蚀-时变动载荷耦合作用下主缆-主鞍座动态接触和微滑移机理，提出基于内、外部摩擦腐蚀疲劳损伤的主缆承载安全系数模型以及充分考虑温度-电化学腐蚀-时变动载荷的主缆-主鞍座抗滑安全系数模型，建立主缆承载安全系数、抗滑安全系数与悬索桥设计参数和环境条件（温度、风和电解质腐蚀溶液）之间的关联关系，确定影响主缆服役安全性的主要因素，提出提高主缆服役安全性的最佳悬索桥设计参数。研究成果对提高主缆服役安全性和保障大跨多塔悬索桥结构安全性有着重要的理论意义。

大跨度多塔悬索桥广泛应用于跨江、跨海桥梁建设，其主缆承载安全性和抗滑安全性直接关系到悬索桥结构安全性。本项目以大跨度多塔悬索桥主缆为研究对象，围绕“主缆摩擦腐蚀疲劳/动态微滑移-主缆承载/抗滑安全性-主缆服役安全性”这一主线，建立了大跨度三塔悬索桥全桥有限元模型和风-车-桥系统耦合动力学模型，研究了主缆时变载荷、振动状态和摩擦疲劳损伤参数及其受到风参数和悬索桥设计参数的影响规律，发现风速和垂跨比增加导致主缆承受载荷增大，不同主缆-索鞍接触位置摩擦疲劳损伤参数动态变化。研制了温度效应下主缆钢丝腐蚀磨损试验机和摩擦腐蚀疲劳试验机，揭示了主缆钢丝腐蚀磨损机理和定量表征模型，探究了不同摩擦配副材料时主缆钢丝摩擦腐蚀疲劳磨损劣化行为，建立了温度和电化学腐蚀效应下主缆内、外部摩擦腐蚀疲劳损伤演化模型，发现摩擦配副材料为鞍槽、温度较高和有电解质腐蚀溶液时主缆钢丝摩擦腐蚀疲劳损伤更严重。研制了主缆-鞍座动态接触和微滑移试验平台，探究了主缆索股/钢丝与鞍座间的动态接触与微滑移机理和定量表征模型，发现主缆索股/钢丝与鞍座间接触状态分为黏着区、部分滑移区、完全滑移区三个分区，上层较下层索股呈现较大的滑移幅值以及较大对应于完全滑移时的最大滑移幅值。建立了不同摩擦配副时主缆钢丝承载强度劣化模型和主缆承载安全系数理论模型，提出了基于主缆接触状态分区的主缆抗滑安全系数计算方法，研究了风速、风载荷、风攻角、垂跨比等悬索桥设计参数和环境条件对主缆静风稳定性的影响规律。研究成果对提高主缆服役安全性、保障大跨多塔悬索桥结构安全性有着重要的理论意义。