MULTI-MODE COUPLED BUFFETING ANALYSIS OF CABLE-STAYED BRIDGES

2001 ◽  
Vol 01 (03) ◽  
pp. 429-453 ◽  
Author(s):  
YEONG-BIN YANG ◽  
SU-VAI MAC ◽  
CHERN-HWA CHEN
Keyword(s):  
Wind Velocity ◽  
Complex Geometry ◽  
Coupling Effect ◽  
Conventional Approach ◽  
Long Span Bridges ◽  
Long Span ◽  
Asymmetric Shape ◽  
Critical Wind Velocity ◽  
Multi Mode ◽  
Cable Stayed Bridges

A procedure for the spectral analysis of buffeting response of long span bridges under unsteady wind loads is developed, with emphasis placed on inclusion of the multi-mode vibrations. The effect of mean wind velocity is considered through the aerodynamic stiffness and damping matrices using the flutter derivatives, while the effect of buffeting through the auto- and cross-power spectral densities. Compared with the conventional approach, the present approach is featured by the fact that no selection has to be made concerning the dominant modes. It can be reasonably used in analyzing cable-stayed bridges of complex geometry or of asymmetric shape, such as the Kao-Ping-Hsi Bridge, where the conventional approach has its limitations. The numerical studies indicate that using the conventional approach, by which the coupling effect is ignored, may significantly overestimate the critical wind velocity, while underestimating the buffeting responses of cable-stayed bridges.

An efficient Cholesky decomposition and applications for the simulation of large-scale random wind velocity fields

2018 ◽  
Vol 22 (6) ◽  
pp. 1255-1265 ◽  
Author(s):  
Yongle Li ◽  
Chuanjin Yu ◽  
Xingyu Chen ◽  
Xinyu Xu ◽  
Koffi Togbenou ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Large Scale ◽  
Spectral Representation ◽  
Cholesky Decomposition ◽  
Velocity Fields ◽  
Data Driven ◽  
Long Span Bridges ◽  
Long Span ◽  
Spectral Representation Method ◽  
Representation Method

A growing number of long-span bridges are under construction across straits or through valleys, where the wind characteristics are complex and inhomogeneous. The simulation of inhomogeneous random wind velocity fields on such long-span bridges with the spectral representation method will require significant computation resources due to the time-consuming issues associated with the Cholesky decomposition of the power spectrum density matrixes. In order to improve the efficiency of the decomposition, a novel and efficient formulation of the Cholesky decomposition, called “Band-Limited Cholesky decomposition,” is proposed and corresponding simulation schemes are suggested. The key idea is to convert the coherence matrixes into band matrixes whose decomposition requires less computational cost and storage. Subsequently, each decomposed coherence matrix is also a band matrix with high sparsity. As the zero-valued elements have no contribution to the simulation calculation, the proposed method is further expedited by limiting the calculation to the non-zero elements only. The proposed methods are data-driven ones, which can be applicable broadly for simulating many complicated large-scale random wind velocity fields, especially for the inhomogeneous ones. Through the data-driven strategies presented in the study, a numerical example involving inhomogeneous random wind velocity field simulation on a long-span bridge is performed. Compared to the traditional spectral representation method, the simulation results are with high accuracy and the entire simulation procedure is about 2.5 times faster by the proposed method for the simulation of one hundred wind velocity processes.

Technologies on Replacement of Structural Members in Prestressed Concrete Cable-Stayed Bridges

2012 ◽  
Vol 446-449 ◽  
pp. 1158-1166 ◽  
Author(s):  
Hong Jiang Li
Keyword(s):  
Prestressed Concrete ◽  
Engineering Application ◽  
Practical Experience ◽  
Structural Condition ◽  
Structural Members ◽  
Long Span Bridges ◽  
Long Span ◽  
Sustainable Operation ◽  
Key Techniques ◽  
Cable Stayed Bridges

Different from traditional strengthening methods, the technology on replacement of structural members is a new strengthening concept for solving the problem of local failures in prestressed concrete cable-stayed bridges. To clarify the characteristics and realization ways of this technology, practical experience and latest achievements of strengthening prestressed concrete cable-stayed bridges in recent years in China were summarized comprehensively, such as replacement of stay cables, replacement of closure segment, replacement of tension rocker bearing cables at subsidiary piers, et al. Forms of Special diseases were described, and their failure mechanisms were given. Then calculation methods and key techniques of these strengthening ways were introduced. Engineering application and practice showed, the technology on replacement of structural members is a system engineering, namely, not only new structural members should meet the mechanical requirements of their own, but also the structural condition of whole bridge should be improved through replacing structural members. Establishment and development of this technology had important and far-reaching significance to promote the technical level of strengthening long-span bridges under the condition of special diseases and ensure bridges in the sate of safe and sustainable operation.

scholarly journals Serviceability Assessment Method of Stay Cables with Vibration Control Using First-Passage Probability

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Seunghoo Jeong ◽  
Young-Joo Lee ◽  
Sung-Han Sim
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Principal Component ◽  
Assessment Method ◽  
Stay Cable ◽  
First Passage ◽  
Long Span Bridges ◽  
Long Span ◽  
Stay Cables ◽  
Cable Stayed Bridges

As the construction of long-span bridges such as cable-stayed bridges increases worldwide, maintaining bridge serviceability and operability has become an important issue in civil engineering. The stay cable is a principal component of cable-stayed bridges and is generally lightly damped and intrinsically vulnerable to vibration. Excessive vibrations in stay cables can potentially cause long-term fatigue accumulation and serviceability issues. Previous studies have mainly focused on the mitigation of cable vibration within an acceptable operational level, while little attention has been paid to the quantitative assessment of serviceability enhancement provided by vibration control. This study accordingly proposed and evaluated a serviceability assessment method for stay cables equipped with vibration control. Cable serviceability failure was defined according to the range of acceptable cable responses provided in most bridge design codes. The cable serviceability failure probability was then determined by means of the first-passage problem using VanMarcke’s approximation. The proposed approach effectively allows the probability of serviceability failure to be calculated depending on the properties of any installed vibration control method. To demonstrate the proposed method, the stay cables of the Second Jindo Bridge in South Korea were evaluated and the analysis results accurately reflected cable behavior during a known wind event and show that the appropriate selection of vibration control method and properties can effectively reduce the probability of serviceability failure.

Simulation of Stochastic Wind Velocity Field on Long-Span Bridges

2001 ◽  
Vol 127 (4) ◽  
pp. 408-409 ◽  
Author(s):  
Chunhua Liu ◽  
Luyu Wang ◽  
Yinghong Cao
Keyword(s):  
Velocity Field ◽  
Wind Velocity ◽  
Long Span Bridges ◽  
Long Span

Sustainability design strategies for cable-stayed bridges

2019 ◽  
Author(s):  
Juan A. Sobrino
Keyword(s):  
Economic Benefits ◽  
Design Strategies ◽  
Long Span Bridges ◽  
Long Span ◽  
Sustainability Strategies ◽  
The Social ◽  
Relevant Role ◽  
Magdalena River ◽  
Local Materials ◽  
Cable Stayed Bridges

<p>Sustainability design considerations play a relevant role in long span bridges. In addition to the social and economic benefits to communities, a good design must be respectfully integrated into the environment and implement other sustainability strategies: prioritizing the use of local materials and labour, and design for durability to extend its lifetime. Minimization of the amount of materials, even with solutions that require more labour, is also an unrecognized strategy to reduce the carbon print.</p><p>The paper presents the sustainability strategies utilized in the design of two cable-stayed bridges recently completed in Colombia: The Hisgaura Bridge and the Magdalena River crossing at Honda. The design of both bridges has been driven by a combination of various factors, all aligned with sustainability practices, such as minimum impact on the natural environment, use of light-weight structures to minimize consumption of materials, use of local materials and labor, along with constructability and cost considerations.</p><p>The Hisgaura bridge is a concrete cable-stayed structure with a main span of 330 m and 148 m tall pylons that is one of the tallest bridges in Latin-America. The Honda bridge is a similar structure with a main span of 247 m over the longest river in Colombia.</p>

Research on Temperature Influences in Cable-Stayed Bridges’ Health Monitoring

2012 ◽  
Vol 188 ◽  
pp. 162-167 ◽  
Author(s):  
Chang Rong Yao ◽  
Ya Dong Li
Keyword(s):  
Health Monitoring ◽  
Temperature Fields ◽  
Effect Of Temperature ◽  
Long Span Bridges ◽  
Bridge Health Monitoring ◽  
Long Span ◽  
Monitoring Strategies ◽  
Structure Monitoring ◽  
Structural Responses ◽  
Cable Stayed Bridges

The health monitoring for long-span bridges has become a hotspot in civil engineering. However, because of the complexity and particularity in bridge structure, monitoring variables are greatly influenced by environmental factors, which results in more difficulties in evaluation. The paper analyzes structural responses in different temperature fields, and the results show that effect of temperature difference among members and temperature gradient are remarkable on structures. The results may be of reference for formulation of bridge health monitoring strategies.

Large Bridges Recently Built in Poland

2018 ◽  
Author(s):  
Robert Toczkiewicz ◽  
Jan Biliszczuk ◽  
Marco Teichgraeber
Keyword(s):  
Construction Technology ◽  
Structural Configuration ◽  
Arch Bridge ◽  
Long Span Bridges ◽  
The Road ◽  
Long Span ◽  
Railway Infrastructure ◽  
Cable Stayed Bridges

<p>The road and railway infrastructure in Poland has been intensively developed and modernized for the last years. Around 300 new bridges are built annually. Among the new structures there is a group of modern long span bridges.</p> <p>This paper presents examples of selected, most interesting large road bridges built in recent years in Poland. The following structures are described:</p><ul><li> <p>two largest extradosed bridges in Europe – with spans exceeding 200 m;</p></li><li> <p>the largest arch bridge in Poland with 270 m long fixed arches and an expressway bridge with 200 m long arch span;</p></li><li> <p>two cable-stayed bridges.</p> <p>Structural configuration and construction technology of the above mentioned bridges are described.</p>

An Improved Flutter Analytical Method for Bridge

2014 ◽  
Vol 587-589 ◽  
pp. 1468-1472
Author(s):  
Guo Fang Chen ◽  
Wei Xu ◽  
Bao Chu Yu
Keyword(s):  
Wind Velocity ◽  
Damping Ratio ◽  
Classical Case ◽  
Pulse Load ◽  
Fe Model ◽  
Transient Dynamic Analysis ◽  
Long Span Bridges ◽  
Long Span ◽  
Stiffness And Damping

With the help of the commercial FE package ANSYS, this paper presents a finite element (FE) model for analyzing coupled flutter of long-span bridges. This model models the aero-elastic forces acting on the bridge utilizing a specific user-defined element Matrix27 in ANSYS, by which stiffness and damping matrices can be expressed in terms of the reduced wind velocity and flutter derivatives. Taking advantage of this FE model, Transient dynamic analysis is carried out to determine the dynamic response of a structure under the action of pulse load, of which the damping ratio can be obtained by considering response peaks which are several cycles apart. The condition for onset of flutter instability turns into that, at a certain wind velocity, the structural system incorporating fictitious Matrix27 elements does simple harmonic vibration with zero damping ratios or near zero one. The damping ratio is completely calculated in post-analysis of ANSYS and the initial frequency is given by any value and the last frequency can be got by iterating several times. In order to validate the developed procedure, a classical case study on three hundred meter simple supported beam is provided.

Optimization of Pre-Tensioning Cable Forces in Highly Redundant Cable-Stayed Bridges

2015 ◽  
Vol 15 (01) ◽  
pp. 1540005 ◽  
Author(s):  
Banafsheh Asgari ◽  
Siti Aminah Osman ◽  
Azlan Bin Adnan
Keyword(s):  
Structural Performance ◽  
Fe Model ◽  
Optimization Strategy ◽  
Unit Load ◽  
Long Span Bridges ◽  
Long Span ◽  
Moment Distribution ◽  
Unit Load Method ◽  
Cable Forces ◽  
Cable Stayed Bridges

Cable-stayed bridges have been developing rapidly in the last decade and have become one of the most popular types of long-span bridges. One of the important issues in the design and analysis of cable-stayed bridges is determining the pre-tensioning cable forces that optimize the structural performance of the bridge. Appropriate pre-tensioning cable forces improve the damaging effect of unbalanced loading due to the deck dead load. Because the cable-stayed structure is a highly undetermined system, there is no unique solution for directly calculating the initial cable forces. Numerous studies have been conducted on the specification of cable pre-tensioning forces for cable-stayed bridges. However, most of the proposed methods are limited in their ability to optimize the structural performance. This paper presents an effective multi-constraint optimization strategy for cable-stayed bridges based on the application of an inverse problem through unit load method (ULM). The proposed method results in less stresses in the bridge members, more stability and a shorter simulation time than the existing approaches. The finite element (FE) model of the Tatara Bridge in Japan is considered in this study. The results show that the proposed method successfully restricts the pylon displacement and establishes a uniform deck moment distribution in the simulated cable-stayed bridge; thus, it might be a useful tool for designing other long-span cable-stayed bridges.

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