Development of structural countermeasures against instability phenomena of long-span cable-stayd bridges

大跨斜拉桥失稳现象结构对策研究进展

• 批准号: 05555124
• 负责人: ITO Manabu
• 金额: $ 9.98万
• 依托单位: Saitama University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05555124/
• 关键词: Cable-Stayd Bridges; Load Carrying Capacity; Nonlinear Analysis; Instability Phenomena; Damping; Tuned Mass Damper

The objective of this research is to establish structural countermeasures against instability phenomena in long-span cable-stayd bridges. The instability phenomena, such as buckling due to static loading and wind-induced vibration, are not significant for cable-stayd bridges with conventional range of the span length. For extremely long-span cable-stayd bridges with a span of more than 1000 m, however, the instability phenomena must be paid attention in design stages. In the present research, three span cable-stayd bridges with a multi-fan cable system are considered as a standard cable-stayd bridge.The main results obtained in the present research are as follows :1.It is shown that the modified E_f method is applicable to evaluate the load-carrying capacity of the girders in cable-stayd bridges with spans above 800 m, where the bending stress is small compared with the normal stress due to the axial force.2.Based on the E_f method, a rational design method for the buckling of the girders is proposed.3.To improve the load carrying capacity of the girders, elastic supports of the girders in the longitudinal direction and reinforcement of the girders are considered as recommendable countermeasures.4.A numerical method to find the initial configuration of cable-stayd bridges under dead load is developed. The present method is required for the finite displacement analysis to evaluate the load-carrying capacity of flexible cable-stayd bridges.5.Damping characteristics of stay in cable in cable-stayd bridges are investigated on the basis of experimental data as well as energy analysis. The effects of mechanical countermeasures against wind-induced vibrations, i.e., cable-cross tie and viscous damper on damping is clarified. Furthermore universal estimation curve of damping is proposed for design of viscous damper.

本研究的目的是建立大跨度斜拉桥不稳定现象的结构对策。在常规跨度范围内，斜拉桥的失稳现象，如静载屈曲和风致振动，并不显著。但对于跨度超过1000 m的超大跨度斜拉桥，其失稳现象在设计阶段就必须引起重视。本文将三跨多扇索体系斜拉桥视为标准斜拉桥，主要研究结果如下：1.对跨径在800 m以上的斜拉桥主梁的承载能力进行了研究，结果表明：修正的E_f法适用于主梁的承载能力评估，因为主梁的弯曲应力与轴力引起的正应力相比较小; 2.基于E_f法，提出了主梁屈曲的合理设计方法; 3.为了提高主梁的承载能力，提出了确定斜拉桥恒载初始线形的数值方法。该方法可用于柔性斜拉桥承载能力的有限位移分析。5.在试验数据和能量分析的基础上，对斜拉桥拉索的阻尼特性进行了研究。机械措施对风致振动的影响，即，阐述了斜拉索-横拉杆和粘滞阻尼器对阻尼的影响。并提出了通用的阻尼估算曲线，可用于粘滞阻尼器的设计。

项目成果

前田研一 他: "長大斜張橋の立体有限変位解析" 土木学会構造工学論文集. Vol.41A. 443-454 (1995)

Kenichi Maeda 等人：“长斜拉桥的三维有限位移分析”日本土木工程师学会结构工程学报第 41A 卷（1995 年）。

M.Nagai et al.: "Applicability of the E_f method and design method for evaluating the load-carrying capacity of girders in cable-stayd bridges" J.of Structural Engineering. Vol.41A,in press. (1995)

M.Nagai 等人：“E_f 方法和设计方法用于评估斜拉桥大梁承载能力的适用性”J.of Structural Engineering。

Masatsugu NAGAI: "Estimation of ultimate strength of cable-stayed girders by E_f method" Proc.New Requirements for Structures and their Reliablity. (1994)

Masatsugu NAGAI：“E_f 法斜拉梁极限强度估算”Proc.结构及其可靠性的新要求。

M.Nagai, et al.: "Evaluation of ultimate strength of steel cable-stayd girders by the effective tangent modulus (E_f) method" Proc.of new requirements for structures and their reliability. 213-218 (1994)

M.Nagai 等人：“通过有效切线模量 (E_f) 法评估钢斜拉梁的极限强度”Proc.of 新的结构要求及其可靠性。

M.Nagai and Y.Fujino: "Instability issues in extremely long-span steel cable-stayd bridges" Proc.of the third symposium on Straight Crossing. 94. 271-276 (1994)

M.Nagai 和 Y.Fujino：“极大跨度钢斜拉桥的不稳定问题”第三届直交研讨会论文集。