Cable-stayed Bridge Research Articles

A Model of Interaction of Rigid Fibers in an Orthotropic Composite Rope

The purpose of research is to construct an algorithm for calculating a stress-strain state of a multilayer orthotropic composite rope. Research methodology involves constructing and solving the interaction model of parallel reinforcing rigid fiber elements regularly placed in layers connected through an elastic material. A method for calculating a stress-strain state of a multilayer orthotropic composite rope is developed. The scientific novelty of research is in the establishment of a dependency for distribution of internal loading forces in reinforcing rigid fibers on stay rope parameters. The distribution of internal loading forces in reinforcing fibers depends on the amount and relative location of fibers in a stay rope. Along the length, the stress-strain state of a rope depends on a square root of the ratio of shear modulus of elastic matrix and tensile rigidity of fibers. The practical value of the research is in that the presented method allows determining the rope stress-strain state during the designing stage of a permanent structure. This is based on structural parameters and mechanical properties of components of a composite rope and conditions of its interaction with the structure, thereby increasing reliability and operation efficiency of the structure, in particular, the cable-stayed bridge.

Static Performance of Multi-Span Cable-stayed Bridge: A Review

The use of multi-span cable-stayed bridge is becoming more common. By collecting a large number of domestic literature in China, this paper mainly summarizes the research results of different research methods on the static performance of multi-span cable-stayed bridges. It shows the research on the mechanical properties of multi-tower cable-stayed bridges by different Chinese scholars. It has reference for the study of static performance of multi-span cable-stayed bridge. It is foreseeable that the future research on multi-tower cable-stayed bridges will develop in the direction of ' physical ' - 'AI ' combination.

Anomaly detection in bridge structural health monitoring via 1D-LBP and statistical feature fusion

Over the past few years, numerous bridges have been equipped with structural health monitoring (SHM) systems to continuously monitor critical structural parameters, enabling early detection of potential issues and timely maintenance. However, the monitoring data frequently contain anomalies due to various interferences during the acquisition and transmission processes. To address this, this paper proposes a robust and efficient anomaly detection and classification method. The method extracts one-dimensional local binary pattern (1D-LBP) features and time-domain statistical features from the monitoring data, fusing them into a comprehensive feature representation. These fused features are then input into an extreme gradient boosting (XG-Boost) classifier for anomaly detection. Additionally, a 1D-LBP feature simplification method is introduced to enhance detection efficiency. The effectiveness of the proposed method was validated using monitoring data from a long-span cable-stayed bridge SHM system. Experimental results demonstrate the excellent performance of the method in terms of detection accuracy and efficiency.

VIV mechanisms of a non-streamlined bridge deck equipped with traffic barriers

Vortex-induced vibration (VIV) has been addressed in the literature mostly for quasi-streamlined and shallow π-deck sections, typical of long-span bridges, since the latter are particularly prone to wind-induced oscillations. In contrast, although full-scale observations demonstrate that even steel-box girder bridges, usually characterized by a shorter span length if compared to suspension and cable-stayed bridges, can experience a violent VIV response, systematic studies for these bluffer cross-section geometries are less frequent. In addition, the aerodynamic optimization of non-structural additions (barriers, screens, fairings) is rarely carried out for this bridge typology. Therefore, a wind tunnel investigation is conducted on a non-streamlined box-girder sectional model (inspired by the Volgograd Bridge, Russia) equipped with two typologies of traffic barriers giving rise to a large ratio of barrier height to deck width. A realistic range of angles of attack (from −3° to 3°) are considered, and static forces, aeroelastic vibrations and wake velocity fluctuations are measured. A large and even unexpected variability in the vibration amplitude and lock-in curve pattern is found, emphasizing the possible existence of competing excitation mechanisms. Indeed, low-porosity barriers can alter the characteristics of vortex shedding, in particular creating a cavity on the upper side of the deck, which is known to foster the impinging-shear-layer instability, as in H-shaped sections. This vortex-shedding mechanism may co-exist with Kármán-vortex shedding and may be responsible for significant anticipation of the VIV onset compared to the predictions based on the Strouhal number measured during static tests. The intensity of a secondary excitation mechanism and its interaction with the dominant mechanism strongly depend on the angle of attack and is largely responsible for profound changes in the VIV bridge response, both in terms of qualitative pattern and peak amplitude. In some cases, the tracks of these competing vortex-shedding mechanisms are even clearly visible in the VIV response curves of the tested bridge model. Finally, the wind tunnel results are also reconsidered based on the quasi-steady theory, highlighting some, even qualitative, discrepancies.

LEVERAGING LOTUS SEEDS’ DISTRIBUTION PATTERNS FOR FRACTAL SUPER-ROPE OPTIMIZATION

The seeds within a lotus seedpod are distributed in an orderly fashion and safeguarded within a secure packaging system. The distribution law is thus revealed, and the packaging mechanism can be emulated for contemporary applications. This paper presents a novel and ingenious method for optimizing fractal super-ropes, inspired by the captivating distribution patterns observed in lotus seeds. The distinctive configuration of the lotus seed represents a model of natural optimization, offering insights that can enhance the exceptional performance and multifaceted functionality of super-ropes utilized in the construction of formidable aircraft carriers, elegantly designed cable-stayed bridges, and stab, bulletproof fabrics. The lotus seedpod provides the fundamental structural framework upon which super-ropes with a sophisticated hierarchical configuration are meticulously constructed. The five super-ropes are presented for detailed examination, offering a promising avenue for further investigation. This paper presents a novel geometrical approach to the optimal design of super-ropes, thereby establishing a promising foundation for extensive future research.

Dynamic response and tension estimation of stay cables with disturbed images acquired from vision sensors

ABSTRACT This study introduces a novel approach to measure cable responses of such bridges using a vision sensor comprising a digital camcorder mounted on a tripod. Prioritizing simplicity and efficiency, this setup requires minimal equipment. The sensor is strategically positioned to ensure the target cable remains within the camcorder’s field of view. However, operational bridge imagery is frequently disturbed by vehicular traffic, leading to defocusing and blurring due to the camcorder’s automatic focus adjustments. These disturbances complicate the identification of reference points essential for accurate cable response measurements, potentially skewing results. To address this, we apply an image quality evaluation method to distinguish reference points from disturbed images, mitigating the impact of these disturbances on measurement accuracy. We evaluated the method’s effectiveness in estimating cable tension under disturbances by capturing images of an operational cable-stayed bridge experiencing ambient vibrations. Cable tension estimations were derived from the analysed responses using the vibration method and validated against data from a long-term monitoring accelerometer. This comparison highlights the potential of the proposed vision sensor method to enhance the accuracy of cable tension measurements in cable-stayed bridges, even in the presence of disturbed images.

Vision-based identification of cable tensions and finite element model verification of a cable-stayed bridge

Vision-based identification of cable tensions and finite element model verification of a cable-stayed bridge

A NSGA-II-based approach for optimizing structural component pre-reinforcement to enhance cable-stayed bridge resilience

As critical transportation nodes, the resilience of cable-stayed bridges has always been a focal point of interest. This paper proposes an optimization decision framework for the pre-seismic reinforcement of cable-stayed bridges based on the NSGA-II algorithm, considering temporal, economic, and performance resilience. In this method, time, seismic resilience, and cost efficiency are used as resilience evaluation indicators for the pre-seismic reinforcement stage of cable-stayed bridges. Based on the NSGA-II algorithm, optimized results for the pre-seismic reinforcement sequence are provided. An actual cable-stayed bridge is used as an example to illustrate the effectiveness of this method. The results show that, when performance resilience is used as the primary objective function, the optimization achieved through this decision framework can reduce time by 2.0%, improve economic resilience by 17.9%, and enhance seismic resilience by 1.8%. If economic resilience is used as the primary objective function, time can be reduced by 2.5%, while economic resilience is increased by 43.1%, with a slight improvement in performance resilience (0.7%).

Experimental study on the aerodynamic force and vibration of a scratched stay cable perpendicular to the wind

The wind load and wind-induced vibration of stay cables, as the primary load-bearing component in cable-stayed bridges, are highly important. Inevitably, cables experience scratches during production, transportation, and installation. Scratches may have an important effect on a cable's aerodynamic force and wind-induced vibration. Consequently, three sectional cable models with varying scratches were prepared for wind tunnel tests. The incoming wind was perpendicular to the cable model. The aerodynamic and vibration responses in precritical, critical Reynolds number regions were investigated. The results showed that scratched cables exhibit Reynolds number effects similar to those of smooth cables. Within attack angles ranging from 50° to 85°, scratching significantly reduced the corresponding Reynolds numbers of the TrBL0-1 and TrBL1-2 transitions. This caused the scratched cable to vibrate substantially at a lower Reynolds number (wind speed) than the smooth cable. There is a smaller attack angle range between 50° and 90° in which scratches cause the average lift coefficient to climb slowly with the Reynolds number, without a bistable phenomenon. This implies that there is no significant vibration. The critical Reynolds number effect effectively predicts the vibration of the scratched cable, and the complex flow in the critical Reynolds number region limits the accuracy of the Den Hartog criterion.

Study on the Effect of Temperature on the Alignment of a Long-Span Steel–Concrete Composite Beam Track Cable-Stayed Bridge

In order to study the effect of temperature on the alignment of a long-span special track bridge, this paper provides a theoretical basis and technical support for bridge design, construction and later operation. This research established the section model of the steel-hybrid beam by COMSOL, and the internal temperature field, transverse temperature, and vertical temperature gradient were analyzed. The Midas Civil bridge model analysis system was established to investigate the influence of temperature difference and temperature gradient on the vertical deformation of the whole bridge. Based on the temperature and displacement monitoring system of the Chongqing Nanjimen track bridge, the temperature and displacement data in 2023 were obtained for comparative analysis. The results show that the temperature field inside the composite beam presents a nonlinear distribution, the daily temperature difference can reach 26.0 °C, and there is a significant temperature gradient between the steel beam and the concrete. The highest temperature is 60.3 °C at 15:00 when the temperature difference between the upper and lower edges of the concrete slab is 11.1 °C, and the daily transverse temperature gradient is 3.2 °C, 5.3 °C and 7.4 °C, respectively. Under the temperature difference in the system, the maximum displacement of the main beam is 92.3 mm, and the mid-span displacement is 132.1 mm under the positive temperature difference. Based on the measured data for the whole year, it is found that the displacement of the main beam under the combined action of ambient temperature and solar radiation significantly exceeds the influence of a single temperature. The research shows that temperature change has an important impact on the stability and durability of the bridge, and temperature monitoring and management should be strengthened in the design and operation stage to ensure the bridge’s safety and smooth operation of the train.

A Framework for Evaluating the Reasonable Internal Force State of the Cable-Stayed Bridge Without Backstays

The synchronous construction of the pylon and cables of a cable-stayed bridge without backstays has the characteristics of a short construction period and reduced support costs. However, it also increases the difficulty of construction control, making the reasonable completion state of the bridge more complex. To investigate the impact of various load parameters on the structural state of a cable-stayed bridge without backstays during the synchronous construction process, and to ensure a rational final bridge state, this study proposes an assessment framework for evaluating the internal forces of the bridge. The framework initially uses the response surface method to establish explicit equations relating the control indicators of the bridge’s final state to various load parameters. Subsequently, through sensitivity analysis, the degree of influence of each load parameter on the structural response of the cable-stayed bridge without backstays is examined. The most sensitive factors are identified to create a bridge parameter influence library, which helps reduce computational costs. Based on this, a method for controlling construction errors and predicting cable forces is proposed. This method utilizes the pre-established bridge parameter influence library, combined with the internal force state of the bridge at the current construction stage, to accurately predict the tension force of the stay cables in the subsequent stage, thereby ensuring a rational final bridge state. The framework is ultimately validated through a case study of the Longgun River Bridge to assess its rationality and effectiveness.

Reliability and durability assessment of bridge stay cables

An algorithm for the reliability and durability assessment of stay cables in bridges is presented in this study enabling their probability of failure and a safe working period to be determined under various loading scenarios. The algorithm was originally developed based on data collected from an extensive structural monitoring campaign of the biggest single-pylon concrete cable-stayed bridge in Poland and used to assess the durability of its suspension system. It was then modified to be suitable for the evaluation of stay-cables subjected to wind excitation and structural reliability of the suspension system in a real steel bridge where permanent plastic deformations occurred in the anchor zones of the stay cables. The algorithm takes into account analytical models describing the stay cables and their numerical finite element models (FEM). As such, it is a universal tool having a wide range of applications, also beyond stay cables often encountered in medium- and long-span bridges forming a critical part of the civil engineering infrastructure.

Response of Guiana dolphins to the construction of a bridge in Ilhéus, Northeastern Brazil.

This study aimed to investigate whether the use of space and movements of Guiana dolphins were altered during the construction of a cable-stayed bridge at the mouth of the Cachoeira River estuary in Ilhéus, Brazil. We described and compared the visitation rate, use of space, and movements of the Guiana dolphins across two periods: before the construction began (2015-2016) and during the construction of the bridge (2017-2020). A theodolite and a total station were used to observe and record the trajectories of the dolphins. From these trajectories, we estimated the Utilization Distribution (UD) using the biased random bridge kernel (BRBK) method, the area of use, and the core area, based on the 95% and 50% BRBK density, respectively. The dolphins did not change their visitation frequency to the estuary. No significant change in area fidelity was identified by comparing the overlap of areas used during two-month periods. No change occurred in the velocity and linearity of the trajectories of the dolphins swimming close to the bridge. However, contrary to expectations, the results indicated an increase in the use of areas close to the bridge during its construction. This may have been caused by the change in the distribution of their prey in the estuary due to the emergence of a sandbank near the bridge. Bridge construction work seems not to have directly affected the Guiana dolphins' use of the area, but the impact of the construction on the local topography has changed their areas of use and core areas of activity.

Response analysis of a long-span cable-stayed bridge with ultra-high piles subjected to near-fault ground motions considering deep-water, sedimentation, local site, and wave-passage effect

The objective of this study is to examine the dynamic response behavior of a long-span cable-stayed bridge with ultra-high piles subjected to near-fault ground motions, comprehensively considering deep-water, sedimentation, local site, and wave-passage effects. Firstly, a 3D finite element (FE) model of the long-span cable-stayed bridge with ultra-high piles (Approximately 105 m) and a tower height of 216.4 m was established using Midas software. The deep-water, sedimentation, local site, and wave-passage effects were synthetically considered in this FE model. The FE model incorporates the sag effect of the stayed cable and the pile-soil interaction, enabling a detailed seismic analysis. Secondly, the examined near-fault ground motions with long-period velocity pulses were selected from the PEER database according to the design acceleration response spectrum with a fortification intensity of VIII degrees. Finally, nonlinear time history analyses of the selected long-span cable-stayed bridge, subjected to spatial near-fault ground motions including local site effect and wave-passage effect, were conducted, and the responses of critical design sections and points in structures were examined and evaluated. The results demonstrate that long-period velocity pulses can significantly affect the structural responses, while deep-water and sedimentation effects do not have a significant impact on the dynamic responses of long-span cable-stayed bridges. For the local site effect, the softer the soil at the support site and the greater the difference in soil conditions at the support, the larger the structural response. Regarding the wave effect, the structural response will increase or decrease depending on the magnitude of the wave speed and the span length between towers.

Modal analysis of natural dynamic frequency for a double deck cable-stayed steel bridge by using finite element method

Double-deck cable-stayed bridges are appropriate when there is a high traffic volume and little space for the structure. They combine road and rail transit to maximize the utilization of bridge structures and tackle traffic issues. This study investigates the fluctuations in the modal properties caused by several factors that impact the modal characteristics of bridges. The aim is to ascertain the system’s inherent frequencies, associated natural periods, and mode shapes. The modal analysis inquiry was conducted utilizing a software model grounded in the finite element method. The bridge deck slab, cable, pier, and pylon are discretized utilizing SHELL 181, CABLE 280, and BEAM 188 elements in this finite element model. The model’s dependability was validated by mesh convergence analysis and comparison with findings from prior research investigations. The cumulative mass participation factor analysis reveals that the bridge induces vibrations in 90% of the mass associated with the first five modes in the research of cumulative modal vibration. The application of prestressing force has significantly increased the natural frequencies of the bridges, resulting in a large rise. An increase in the damping ratio leads to a reduction in the natural frequency. Several factors, such as the existence or absence of prestressing force and different damping ratios in the bridge system, will affect free vibration results. Additionally, it can provide the foundation for subsequent fatigue analysis related to different dynamic loads.

Optimizing vortex-induced vibration suppression in π-shaped girders using wind tunnel testing and CFD analysis

This investigation meticulously explores the vortex-induced vibration (VIV) characteristics in Π-shaped girders within long-span cable-stayed bridges, presenting novel VIV mitigation techniques. Employing detailed wind tunnel evaluations of a 1:50 scale model alongside computational fluid dynamics (CFD) analyses to model the two-dimensional flow around the girder, this study reveals the formation and shedding of vortices behind the railings and main steel girder, which significantly contribute to VIV in such structures. The introduction of horizontal splitter plates, one m in width, in conjunction with two-m-wide V-shaped guide vanes, was found to substantially reduce the VIV amplitude of the Π-shaped girder, minimizing vortex generation on the deck’s sides and dramatically reducing the maximum vertical VIV amplitude from 208.75 mm to only 5.56 mm. CFD simulations confirm the effectiveness of these measures in suppressing Karman vortex street formation, thereby significantly improving downstream airflow characteristics. These findings offer pivotal insights for the advancement of bridge design and the proactive management of VIV, showcasing the potential of integrated aerodynamic modifications to enhance structural resilience and performance.

Improvement of Stockbridge Damper Design for Cable-Stayed Bridges

Stockbridge dampers are widely used to mitigate the vibrations of cable-stayed bridges and of many other cable-suspended or cable structures exposed to the action of pedestrians, traffic or wind load. Within the current research work, one of the most effective and likely used damper types, the Stockbridge damper, was investigated to support its design and application within the daily engineering praxis. The Stockbridge damper has a relatively simple structural layout, which ensures its modular design allows it to easily adapt the damper to cables having different dynamic properties (eigenfrequencies, mass, etc.). This paper focuses on two main research areas: (i) to understand the static and dynamic behaviour of the damper and the stay cable interaction to investigate the effectiveness of its damping; (ii) to study the sensitivity of the natural frequencies of the damper to the design parameters. The final aim of the research is to develop a simple design method that is easy to apply in engineering practice and allows the efficient adaptation of the Stockbridge damper to different cable-stayed bridges. Key findings include the recommendation to position the damper at approximately 20% of the cable length for optimal attenuation, the importance of detuning to maintain effectiveness under varying cable forces, and the observation that increasing the damper mass improves efficiency, particularly for detuned elements.

A study of the nonlinear behaviour of the irregular Beni Haroun cable-stayed bridge to progressive seismic failure under SVGM

The progressive failure of the nonlinear irregular Cable-Stayed Bridges (CSBs) under Spatial Variability of Ground Motions (SVGM) counting seismic wave propagation, incoherence effect and site-response effect is investigated. A spectral representation method is used in order to develop a computer code. This code is used to simulate SVGM time histories to be compatible with an overall coherency function and a target response spectrum, A three-dimensional Finite Element Model (FEM) of an asymmetric bridge: the Beni Haroun cable-stayed bridge (CSB) (North Eastern Algeria) is developed in order to include the effects of the main components of SVGM on response parameters in terms of variations of absolute maximum vertical displacements and flexural moments along the deck and on height of short and tall pylons of study CSB, in particular, nonlinear bridge response quantities are examined in terms of rotational ductility demands at the ends of the short and tall piers of the bridge under all components of SVGM. The numerical results are comforted with those obtained assuming uniform seismic excitations. The analysis results reveal, among others, that the bridge responses are very sensitive to the SVGM, with site-response effects being more critical for bridge response than those of incoherence components and wave propagation. As a general trend, it is showed that the assumption of uniform excitation results in much lower ductility demands on bridges than incoherence and site SVGM components and that the latter should be considered for the seismic response assessments and progressive seismic failure studies of irregular cable-stayed bridges.

Experimental verification of the compressive stiffness of high-damping rubber bearings (HDRB) according to STN EN 1337-3 and their effectiveness in seismic isolation for cable-stayed bridges

Experimental verification of the compressive stiffness of high-damping rubber bearings (HDRB) according to STN EN 1337-3 and their effectiveness in seismic isolation for cable-stayed bridges

Modal Frequency Shifts Measured on Xinjiang Bridge Excited by Traveling Vehicles

To excite sufficient vibrations of bridges for more effective modal experiments to take place, traveling vehicles were utilized in many bridge field inspection campaigns in history. However, the dynamics of a bridge subjected to the traveling vehicles are of changed resonant properties compared with those of the same structure with the ambient excitation in nature. Therefore, the field modal experiments employing vehicle excitations might unfavorably lead to shifted measurement results of low-order natural frequencies for long-span bridges of large mass. Using Xinjiang Bridge (a single-tower pre-stressed concrete cable-stayed bridge with spans [Formula: see text]) as the engineering background, this paper validates this technical notion based on reliable physical experiments and numerical simulations and seeks a practical approach to deal with the issue. It is found that the maximum deviation between the low-order modal frequencies measured on Xinjiang Bridge for the vehicle excitation case and those measured for the ambient excitation case (the accurate values) reaches 0.65[Formula: see text]Hz, and the deviation between the lower limit of the usual vehicle excitation’s energy band and the modal frequency measured (factor 1) and the traveling vehicles’ speed (factor 2) are the two key factors influencing the modal frequency shifts. An empirical model to compensate for modal frequencies’ deviations is formulated considering the two key factors accordingly, which is of high-practical significance in future applications of the modal experiments using vehicle excitations to other long-span bridges.