楊永斌臺灣大學:土木工程學研究所陳立人Chen, Li-JenLi-JenChen2007-11-252018-07-092007-11-252018-07-092004http://ntur.lib.ntu.edu.tw//handle/246246/50536纜索在斜張橋的承載機制中,扮演著不可或缺的角色。但出乎意料地,斜張橋纜索在車行載重下的振動問題,或可以更精確地說,由支承運動所引致的纜索振動問題,卻很少成為學者研究的題材。唯近年來釵h工程師常發現,有時即便是在微風且車流量少的情況下,某些特定纜索的振動量竟然大到可以破壞錨定端的披覆材料,此一現象使得纜索振動的問題逐漸受到世人的重視。為了進一步分析纜索振動的問題,在考慮纜索的撓曲勁度下,本文根據受初始張力下纜索的振動方程式,推導出由支承運動而引致纜索振動的解析解。在假設支承運動可經由有限元素法事先分析橋樑求得的情況下,此解可以進一步地推廣至分析斜張橋的纜索振動問題。 傳統上由於缺少一有效分析纜索振動的方法,使得纜索佈置的選擇多取決於美觀考量,鮮少考慮其相對應纜索的動力特性。為了彌補這缺憾,本文將依前所提的纜索分析方法,來探討不同的纜索佈置,對於纜索振動的影響。此外,本文亦會探討斜張橋纜索在斜張橋受序列載重下的動力特性。而由本文的分析可發現,由於斜張橋是一相當複雜的結構系統,有可能因為纜索頻率與橋梁或驅動頻率之間的重合或接近,而造成纜索振動反應被放大的情形。本文各項分析所得的結果,應有助於解釋並進一步減少斜張橋纜索的振動。Cables play an important role in the load-carrying system of cable-stayed bridges. Surprisingly, the problem of vehicle-induced vibration of cables mounted on cable-stayed bridges or, specifically, the problem of cable vibration induced by support motions, received only very limited attention from researchers. Based on the governing differential equation of a cable with initial tension, an exact solution was derived for the cable with support motions, considering the contribution of flexural rigidity. Such a solution is then extended to the analysis of vibration of cables mounted on a cable-stayed bridge under the moving loads, with the support motions of the cables made available by a finite element analysis carried out in advance for the entire bridge. Conventionally, the arrangement of cables is chosen primarily based on the aesthetic considerations, while the corresponding dynamic property of the cables is seldom considered, partly due to the lack of a simple approach for analyzing the cable vibrations. To fill the gap, the influence of arrangement of cables on cable vibration will be investigated in this study, based on the proposed analysis procedure. Furthermore, the dynamic behavior of cables in cables-stayed bridges under serial moving loads will also be studied, from which it is concluded that the responses of cables in cable-stayed bridges will be amplified, when the frequency of the cable concerned coincides with any of the bridge or excitation frequencies. The results presented herein are useful for the design of bridges aimed at reducing the cable vibrations.Acknowledgement (Chinese) I Abstract II Abstract (Chinese) III Table of Contents IV List of Tables VIII List of Figures IX Chapter 1 Introduction 1 1.1 Motivation and Purpose 1 1.2 Literature Review 3 1.3 Layout of Thesis 6 Chapter 2 Development of Cable-Stayed Bridges and Fundamental Cable Problems 8 2.1 Introduction 8 2.2 Development of Cable-Stayed Bridges 8 2.3 Fundamental Analysis of Cable Problems 12 2.3.1 Inextensible Cable 13 2.3.2 Extensible Cable 15 2.3.3 Derivation of Equation of Motion for Cable 17 2.4 Summary 19 Chapter 3 Derivation of Analytic Solution for Cables with Support Motions 20 3.1 Introduction 20 3.2 Analytic Solution for Cables with Support Motions – Ignoring the Effect of Flexural Rigidity 21 3.3 Analytic Solution for Cables with Support Motions – Considering the Effect of Flexural Rigidity 25 3.4 Numerical Example and Comparison 32 3.4.1 Numerical Example 32 3.4.2 Discussion on the Difference between Results by Different Approaches 35 3.5 Summary 36 Chapter 4 Procedure of Analysis for Stay Cables Mounted on Cable-Stayed Bridges 38 4.1 Introduction 38 4.2 The Composition of Cable-Stayed Bridges 39 4.3 Analysis Procedure for Stay Cables Mounted on Cable-Stayed Bridges 42 4.3.1 Introduction 42 4.3.2 Vibration of Cables in a Simple Cable-Stayed Bridge - Nonresonant Case 46 4.3.3 Vibration of Cables in a Simple Cable-Stayed Bridge - Resonant Case 47 4.3.4 Vibration of Cables in a Harp-Type Cable-Stayed Bridge 48 4.3.5 Validity of Assumption Evaluated from the Kinetic Energy Point of View 50 4.4 The Influence of Arrangement of Cables on Cable Vibration 53 4.4.1 Introduction 53 4.4.2 Numerical Analysis – Velocity of Moving load As a Constant 54 4.4.3 Numerical Analysis – Velocity of Moving load as a Parameter 57 4.5 Summary 63 Chapter 5 Analysis of Cables in Cable-Stayed Bridges under Serial Moving Loads .. 64 5.1 Introduction 64 5.2 Introduction of Theory of Vehicle-Induced Vibration on Bridges 65 5.3 Numerical Analysis 70 5.3.1 Bridge Type I – Simple Cable-Stayed Bridge 72 5.3.2 Bridge Type II – Complex Harp-Shaped Cable-Stayed Bridge 76 5.4 Effect of Modal Shapes of Bridges 79 5.4.1 Condition 1: Coincidence of Bridge Frequency with Cable Frequency 79 5.4.2 Condition 2: Coincidence of Excitation Frequency with Bridge Frequency 80 5.5 Summary 82 Chapter 6 Concluding Remarks and Future Works 84 6.1 Concluding Remarks 84 6.2 Future Works 86 References 881808280 bytesapplication/pdfen-US斜張橋共振撓曲勁度車橋互制振動纜索纜索佈置cablecable arrangementcable-stayed bridgeresonancevehicle-bridge interactionflexural rigidityvibration斜張橋纜索在車行載重下之振動分析Vibration Analysis of Cables in Cable-Stayed Bridges due to Moving Loadsthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/50536/1/ntu-93-R91521205-1.pdf