Cable Vibrations in Cable-stayed Bridges

Cable Vibrations in Cable-stayed Bridges
Author: Elsa de Sá Caetano (autor.)
Publisher: IABSE
Total Pages: 191
Release: 2007
Genre: Cable-stayed bridges
ISBN: 3857481153

The present book provides a comprehensive survey on the governing phenomena of cable vibration, both associated with direct action of wind and rain: buffeting, vortex-shedding, wake effects, rain-wind vibration; and resulting from the indirect excitation through anchorage oscillation: external and parametric excitation. Methodologies for assessment of the effects of those phenomena are presented and illustrated by practical examples. Control of cable vibrations is then discussed and state-of-art results on the design of passive control devices are presented.

Vibration and Mode Shapes Analysis of Cable Stayed Bridges Considering Different Structural Parameters

Vibration and Mode Shapes Analysis of Cable Stayed Bridges Considering Different Structural Parameters
Author: Nazim Nariman
Publisher: GRIN Verlag
Total Pages: 36
Release: 2014-02-05
Genre: Technology & Engineering
ISBN: 3656588791

Research Paper (postgraduate) from the year 2014 in the subject Engineering - Civil Engineering, grade: unknown, University of Weimar, language: English, abstract: The vibration characteristic of a cable stayed bridges structure is the main axis of the study in this paper, many structural parameters are used to simulate and determine the effect of vibration on the structural performance by identifying the natural frequencies of the system and the mode shapes that can occur in the real structure. Modeling the stay cables with three famous styles of arrangements such as Harp, Semi Harp and Fan styles, and assigning roller, hinged and fixed boundary conditions on the deck support of the cable stayed bridge, in addition to using two design cases of the girders and pylons dimensions in the global structure for that purpose. Through the use of ABAQUS finite element analysis, the models were generated for each mentioned cases and the results of the frequency linear perturbation step of 10 mode shapes were determined through the simulation of the deformed shapes and the determined values of the natural frequencies of each mode for each case of interest. It was seen that the roller boundary condition was much prone to the early vibration and the stay cables of the direction near to the roller support were vibrated and stressed much more than the other direction compared with the hinged and fixed boundary conditions, and the mode shapes 7, 8, 9 and 10 were the most vibrated cases for all the boundary conditions without any distinction. The week design of the girders and the pylons has the great effect on the vibration of the stay cables, pylons and deck of the structure especially near the roller support direction due to the early vibration of the case of roller support, so the use of cross ties and damping between the stay cables and the girders are very important in the cases of significant vibrations which affect the performance of the cable stayed bridges.

Rain-wind-induced Cable Vibrations in Cable-stayed Bridges

Rain-wind-induced Cable Vibrations in Cable-stayed Bridges
Author: Oscar F. Calle
Publisher:
Total Pages: 91
Release: 2014
Genre: Bridges
ISBN:

This research is aimed at investigating and analyzing the rain-wind-induced cable vibration phenomena experienced in cables of cable-stayed bridges and also the countermeasures employed by engineers to mitigate the large-amplitude vibration problem reported by various researchers around the world. In order to investigate the problem of the water rivulet creation at the top of the cable surface, a single-degree-of-freedom (SDOF) analytical model was developed and analyzed. This thesis studies the aerodynamic instability of cables in cable-stayed bridges by doing literature review of a typical in-situ test, developing a single degree-of-freedom (SDOF) analytical model, and an ANSYS finite element model. Furthermore, a linear viscous damper that acts as a countermeasure to the large amplitudes of vibration is reported and analyzed. The suppression characteristics and damper effectiveness of such countermeasure are summarized.

Inspection and Maintenance of Bridge Stay Cable Systems

Inspection and Maintenance of Bridge Stay Cable Systems
Author: Habib Tabatabai
Publisher: Transportation Research Board
Total Pages: 214
Release: 2005
Genre: Technology & Engineering
ISBN: 0309097606

TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 353: Inspection and Maintenance of Bridge Stay Cable Systems identifies and explains various inspection and maintenance techniques for bridge stay cable systems. It discusses both short- and long-term approaches. The report information on methods for inspections and assessments, including nondestructive testing and evaluation procedures; repair and retrofit; methods for control of cable vibrations, including rainwind vibrations; stay cable fatigue and failure; effectiveness of various inspection and repair methods; limitations of available technologies; and trends and recommendations for future study.

Wind Induced Vibration of Stay Cables

Wind Induced Vibration of Stay Cables
Author:
Publisher:
Total Pages: 140
Release: 2005
Genre: Bridges
ISBN:

This study was conducted in order to develop a set of consistent design guidelines for mitigation of excess cable vibration on cable-stay bridges. In order to accomplish this objective the Project Team started with a thorough review of existing literature to determine the state of knowledge and identify any gaps that must be filled in order to enable the formation of a consistent set of design recommendations. This review indicated that while the rain/wind problem is known in sufficient detail, galloping of dry inclined cables was the most critical wind-induced vibration mechanism in need of further experimental research. A series of wind-tunnel tests was performed to study this mechanism. Analytical and experimental research was performed to study mitigation methods, covering a range of linear and nonlinear dampers and cross-ties. The study also included brief studies on live load induced vibration and establishing driver/pedestrian comfort criteria. Based on the above, design guidelines for mitigation of wind-induced vibrations of stay cables were developed.

Cable Supported Bridges

Cable Supported Bridges
Author: Niels J. Gimsing
Publisher: John Wiley & Sons
Total Pages: 760
Release: 2011-12-30
Genre: Technology & Engineering
ISBN: 1119951879

Fourteen years on from its last edition, Cable Supported Bridges: Concept and Design, Third Edition, has been significantly updated with new material and brand new imagery throughout. Since the appearance of the second edition, the focus on the dynamic response of cable supported bridges has increased, and this development is recognised with two new chapters, covering bridge aerodynamics and other dynamic topics such as pedestrian-induced vibrations and bridge monitoring. This book concentrates on the synthesis of cable supported bridges, suspension as well as cable stayed, covering both design and construction aspects. The emphasis is on the conceptual design phase where the main features of the bridge will be determined. Based on comparative analyses with relatively simple mathematical expressions, the different structural forms are quantified and preliminary optimization demonstrated. This provides a first estimate on dimensions of the main load carrying elements to give in an initial input for mathematical computer models used in the detailed design phase. Key features: Describes evolution and trends within the design and construction of cable supported bridges Describes the response of structures to dynamic actions that have attracted growing attention in recent years Highlights features of the different structural components and their interaction in the entire structural system Presents simple mathematical expressions to give a first estimate on dimensions of the load carrying elements to be used in an initial computer input This comprehensive coverage of the design and construction of cable supported bridges provides an invaluable, tried and tested resource for academics and engineers.

Mitigation of wind-induced vibration of stay cables

Mitigation of wind-induced vibration of stay cables
Author: Sunwoo Park
Publisher:
Total Pages: 101
Release: 2014
Genre: Bridges
ISBN:

Cable-stayed bridges have been recognized as the most efficient and cost effective structural form for medium-to-long-span bridges over the past several decades. With their widespread use, cases of serviceability problems associated with large amplitude vibration of stay cables have been reported. Stay cables are laterally flexible structural members with very low inherent damping and thus are highly susceptible to environmental conditions such as wind and rain/wind combination. Recognition of these problems has led to the incorporation of different types of mitigation measures on many cablestayed bridges around the world. These measures include surface modifications, cable crossties, and external dampers. Modifications to cable surfaces have been widely accepted as a means to mitigate rain/wind vibrations. Recent studies have firmly established the formation of a water rivulet along the upper side of the stay and its interaction with wind flow as the main cause of rain/wind vibrations. Appropriate modifications to exterior cable surfaces effectively disrupt the formation of a water rivulet. The objective of this study is to supplement the existing knowledge base on some of the outstanding issues of stay cable vibrations and to develop technical recommendations that may be incorporated into design guidelines. Specifically, this project focuses on the effectiveness of cable crossties, external dampers, and the combined use of crossties and dampers. Finite element simulations are carried out on the stay cable systems of constructed stay cable bridges under realistic wind forces in order to address these issues. Explicit time-history analysis enabled the performance of stay cable systems with different mitigation strategies to be assessed and compared for their relative advantages and disadvantages.

Wind Effects on Cable-Supported Bridges

Wind Effects on Cable-Supported Bridges
Author:
Publisher:
Total Pages: 334
Release: 2018-05
Genre:
ISBN: 9781642241983

Cable stayed bridges have only become an established solution for long span structures over the last 60 years. This recent ascendency is primarily due to the development of reliable high strength steels for the cables and perhaps more importantly, the advent and widespread use of computers to analyze the complex mathematical models. Cable-stayed bridges are preferred these days as they provide much greater stiffness than the suspension bridge and deformations of the deck under live loads are reduced. A cable stayed bridge has one or more pylons, from which cables support the deck of the bridge. A distinctive feature of the bridge is the cables which run directly from tower to deck, normally forming a fan like pattern or a series of parallel line. The main objective of this book is to review the various wind effects and the different vibrations which are induced due to the wind on cable-stayed bridges. Cable-stayed bridges being more flexible, a proper wind study is inevitable.Wind Effects on Cable-Supported Bridges provides in-depth information to understanding wind effects on cable-stayed bridges; this book uses analytical, numerical and experimental methods to give readers a fundamental and practical understanding of the subject knowledge. It describes the structural behavior of cable-stayed bridges, identifies cable-stayed bridge elements, and discusses their role in supporting the structure. It presents methods of pre-sizing the stays and describes the mathematical procedure that allows optimal tensioning of forces in the stays, so that the structure complies with the design criteria. This book is intended to supplement information from introductory areas through to advanced topics currently being developed from research work. Cable-stayed bridges under wind loading exhibit dynamic behaviors that depend on the aero elastic forces and coupling among vibration modes.