Design Of Cable-stayed Bridges Research Articles

Numerical Investigation of the Shear Lag Effect on a Cable-Stayed Bridge with an Extra-Wide Composite PK Girder

The composite PK (Pasco-Kennewick) girder cable-stayed bridge (CSB) is a trendy structure with a super-wide girder, excellent lateral rigidity, and high wind resistance. However, the shear lag effect (SLE) of the composite PK girder grows severe due to the super-wide deck. Meanwhile, the SLE of the composite PK girder CSB subjected to huge axial forces significantly differs from that of bridges subjected to only bending moment. Therefore, global and local analyses are conducted on a composite PK girder CSB to determine the SLE during construction and after completion. Furthermore, the effective slab width (Beff) of the composite PK girder under combined bending moment and axial force is analyzed. The results can offer guidance and reference for the design and construction of composite PK girder cable-stayed bridges.

Unified framework for stochastic dynamic responses and system reliability analysis of long-span cable-stayed bridges under near-fault ground motions

Long-span cable-stayed bridges are complex systems with numerous components, and prone to failures of multiple components under near-fault ground motions with long-period velocity pulses. The evaluation of dynamic system reliability of cable-stayed bridges is an important challenging issue. In this work, a unified framework for simultaneously determining both the stochastic dynamic responses and system reliabilities of long-span cable-stayed bridges under near-fault stochastic ground motions is proposed based on direct probability integral method (DPIM) with adaptive strategy. Firstly, the 3-dimensional finite element model of typical cable-stayed bridge and the stochastic synthesis model of near-fault ground motions are established. Based on probability density integral equation, new formulas in input probability space of time-variant moments of response are derived. Then, DPIM with adaptive strategy is suggested to calculate the mean value and standard deviation of response via new formulas. Dynamic system reliability of cable-stayed bridge under near-fault stochastic ground motions is evaluated by establishing failure criteria of extreme value mappings of multiple performance functions. Finally, numerical results indicate that the long-period velocity pulse of near-fault motions imposes an important effect, resulting in large mean responses and failure of cables. Failure probability of cables is significantly increased with the occurrence of velocity pulses, which causes the decrease of system reliability of cable-stayed bridge. Thus, the randomness and velocity pulse effect of near-fault ground motions should be seriously considered for reliability-based design and safety assessment of cable-stayed bridges.

Design and Validation of a Fiber-Reinforced Polymer Cable-Stayed Pedestrian Bridge: Human-Induced Actions vs. Comfort Levels.

The investigation into advanced structural materials, such as composite materials, has revealed numerous possibilities within the field of bridge engineering. Glass-fiber-reinforced polymers (GFRPs) are notable among these materials, particularly in footbridge construction, encompassing both arch and cable-stayed designs. While GFRPs boast advantages, such as their high strength-to-weight ratio, they may exhibit some deficiencies, particularly when subjected to dynamic loads induced by wind or pedestrian forces. Two noteworthy global examples are the Lleida arch bridge (Spain, 2001) and the Aberfeldy cable-stayed bridge (Scotland, 1992). These structures have recently undergone comprehensive studies by the authors to assess their behavior when subjected to specific conditions regarding pedestrian traffic and vibrations induced by under-passing trains, as far as Lleida is concerned. The methodologies employed in these studies are detailed herein, incorporating the relevant scientific literature and technical regulations that provide guidance on fundamental principles for bridge design, pedestrian modelling, and acceleration thresholds aimed at minimizing discomfort. While the framework of principles is clear, the regulations are extensive, requiring designers to have a comprehensive understanding of the diverse outcomes achievable through various approaches. Therefore, the provided state-of-the-art overview serves as a roadmap for assessing the performance of an innovative cable-stayed bridge recently proposed by one of the authors. Initially designed with six spans, this prototype has been reconfigured here as a three-span train station overpass. The analyses conducted allowed for the assessment of induced accelerations. According to current accredited standards, the resulting comfort classification is considered minimal, even if, for crowded conditions, more specific studies are required.

Structural and Economical Analysis of Cable-Stayed Bridges

Abstract: Cable-stayed bridges have emerged as prominent structures in modern civil engineering, renowned for their aesthetic appeal, structural efficiency, and economic viability. This review paper provides a comprehensive analysis of the structural and economic aspects of cable-stayed bridges. It encompasses a thorough examination of various design considerations, construction techniques, material selection, and economic factors influencing the feasibility and performance of cable-stayed bridges. Through the synthesis of existing literature and case studies, this paper aims to offer insights into the key factors driving the design, construction, and economic evaluation of cable-stayed bridges, thereby aiding engineers, planners, and decision-makers in making informed choices in bridge infrastructure development projects.

Optimum design of cable-stayed bridges considering cable loss scenarios

Optimum design of cable-stayed bridges considering cable loss scenarios

Shaking table experiment study of a multi-tower cable-stayed bridge with consideration of seismic pounding effect between the main bridge and approach bridge

In this study, a 1/100-scale shaking table experiment was designed and conducted for a multi-tower cable-stayed bridge in order to investigate its seismic response characteristics with consideration of seismic pounding between the main and approach bridges. The test parameters include the expansion gap size and period ratio between the main bridge and the approach bridge. Both the near-field and far-field ground motions were selected to excite the model. Test results indicate that the seismic response of multi-tower cable-stayed bridges is very sensitive to the gap size and a reasonable gap size of expansion joint can mitigate the pounding effect on structural response. In addition, a period ratio close to 2:1 resulted in the most significant pounding effect and should be avoided in the design stage to reduce the collision risk. Moreover, seismic pounding could significantly amplify the relative displacement between the pier and girder of the main bridge elevating the risk of girder unseating. The test results can provide a valuable reference for the seismic design of cable-stayed bridges with multi-tower.

The Design and Construction of Anchor Block Pedestrian Cable-Stayed Bridge on Celebes Island

The Design and Construction of Anchor Block Pedestrian Cable-Stayed Bridge on Celebes Island

Analytical Solution for Longitudinal Anti-Push Stiffness of the Middle Tower of Cross-Cable Multi-Tower Cable-Stayed Bridge

The Queensferry Crossing in Scotland is the first multi-tower cable-stayed bridge with crossed cables in the world. This means that the conceptual design of a cross-cable multi-tower cable-stayed bridge has become a reality. In this paper, the cross-cable action mechanism is studied deeply. Suppose that the small displacement amount at the top of the side tower is ignored. The deformation coordination principle is used twice to analyze the relationship between the horizontal external force and the top displacement amount of the middle tower. Thus, derive the formula for estimating the anti-push stiffness of cross cables to the middle tower of the multi-tower cable-stayed bridge under the influence of the stiffness of the tower and beam. A numerical example is given to verify this. The research results show that the error between the analytical solution and the finite element solution is less than 8%, which meets the conceptual design requirements of cross-cable multi-tower cable-stayed bridges. The cross cables can reduce the deflection of the main beam and improve the stiffness of the bridge. After setting 10 pairs of cross cables, the displacement amount of the middle tower decreases by as high as 51%. The stiffness of the multi-tower cable-stayed bridge increases with an increase in the number of cross cables, but the increasing trend of stiffness gradually slows down. Increasing the stiffness of the tower or beam can improve the structural stiffness to a certain extent, but the effect is much less potent than that of the cross cable in the middle span.

Review of design and innovative construction of steel truss cable-stayed bridges in China

Many steel truss cable-stayed bridges have been built in China in the past two decades, providing a wealth of design and construction experience. This paper provides a review of their development, the structural configurations used, the mechanical characteristics of decks, pylons and cables, and the various innovative construction methods adopted. With main spans now exceeding 1 km, the sturdy structures are mainly used for combined rail-and-road crossings in preference to more flexible suspension bridges. The aim of the paper is to provide a comprehensive and useful reference for further design and construction of steel truss cable-stayed bridges worldwide.

Design and Dynamic Analysis of Cable-Stayed Bridge in STAAD Pro

Design and Dynamic Analysis of Cable-Stayed Bridge in STAAD Pro

Investigation of the Temperature Actions of Bridge Cables Based on Long-Term Measurement and the Gradient Boosted Regression Trees Method

Cable-stayed bridges have been commonly used on high-speed railways. The design, construction, and maintenance of cable-stayed bridges necessitate an accurate assessment of the cable temperature field. However, the temperature fields of cables have not been well established. Therefore, this research aims to investigate the distribution of the temperature field, the time variability of temperatures, and the representative value of temperature actions in stayed cables. A cable segment experiment, spanning over one year, is conducted near the bridge site. Based on the monitoring temperatures and meteorological data, the distribution of the temperature field is studied, and the time variability of cable temperatures is investigated. The findings show that the temperature distribution is generally uniform along the cross-section without a significant temperature gradient, while the amplitudes of the annual cycle variation and daily cycle variation in temperatures are significant. To accurately determine the temperature deformation of a cable, it is necessary to consider both the daily temperature fluctuations and the annual cycle of uniform temperatures. Then, using the gradient boosted regression trees method, the relationship between the cable temperature and multiple environmental variables is explored, and representative cable uniform temperatures for design are obtained by the extreme value analysis. The presented data and results provide a good basis for the operation and maintenance of in-service long-span cable-stayed bridges.

Conceptual Design of Cable-Stayed Bridges Using Graphic Simulation

The paradigm for structural design has been shifted from traditional engineering-oriented to more comprehensive holistic designs that consider visual aspects. Such trends need an integrated strategy to design a structure that follows force flow resulting in a pleasing visual appearance. Graphic statics is perfect for designing structural forms while visualizing structural behavior. Despite the advantages of graphic statics, there are limitations to its use manually in conceptual design, where various design alternatives must be created and compared. The objective of this study is to present the conceptual design of cable-stayed bridges by exploiting the novelty of graphic statics. It also focuses on the rapid prototyping of computer-supported design to overcome the problem of tedious and iterative manual tasks. The generation of form and force diagrams for some representative cable-stayed bridges is first discussed. This is for parametric modeling to generate structural forms with genetic information and to develop into a family of design alternatives by varying the values for predefined input parameters. Then, the information and tasks involved in the development of the form and force diagrams are formalized by using the concept of entity-based model for the computer-supported graphic simulation. The formalized entities are further implemented into the generative algorithms of graphics software that link form and force diagrams through dynamic binding. It is expected that the implemented design tool support designers to perform conceptual design iteratively and interactively by considering structural behaviour and visual silhouette in a balanced way.

Optimal design of cable-stayed bridge and its approach spans under spatially varying ground motions

The out-of-phase vibration between neighboring structures owing to their different vibration characteristics and spatially varying seismic excitations may result in strong impact between the adjacent structural components, which might result in detrimental damage to the structures. To preclude such damage, the gap size of the expansion joint and the vibration period ratio between the adjacent structures should be carefully selected. Herein, the framework of performance-based seismic design (PBSD) is extended to optimize the gap size and period ratio between the cable-stayed bridge and its approach spans under the spatially varying ground motions. Considering the computational burden, an equivalent cable-stayed bridge model is proposed and verified, and then adopted in the optimization process. Based on the multi-stripe analysis (MSA) method, the component fragility curves (pylons, bearings, and local damage) for the typical cable-stayed bridge are derived, and then the corresponding structural fragility functions, namely, repair cost ratios (RCRs) are derived. The optimal gap size and period ratio between main bridge and approach spans could be identified by the proposed optimization framework under both uniform and spatially varying excitations. The analytical results demonstrated that the optimal gap size and period ratio depend on the earthquake characteristics and the excitation methods. The optimized RCR values of the bridge subjected to the spatial varying ground motions are much larger than those of bridge under the uniform excitation.

Experimental and Numerical Studies on Dynamic Response of Parallel Wire Cables Subjected to Close-In Explosions

The recent trend of increasing global terrorist attacks and identified vulnerabilities associated with critical bridges highlights the necessity to protect cable-stayed bridges from terrorist assaults. The cables are the most crucial load-carrying components within the envelope of a cable-stayed bridge, whose failure could result in the progressive collapse of the whole bridge structure with disastrous consequences. However, there is a very limited understanding of the blast effects on cables. This paper presents an experimental and numerical investigation of the blast performance of parallel wire cables under close-in explosions. Field blast tests were conducted on three identical parallel wire cable specimens with varying explosive charge weights. An equivalent beam–shell model was developed in LS-DYNA to reproduce the dynamic response of parallel wire cables subjected to close-in explosions and was comprehensively validated against the experimental results. With the validated numerical modeling techniques, the dynamic behavior of parallel wire cables in a realistic blast scenario of vehicle-borne improvise explosive devices (VBIEDs) detonated on the bridge deck was investigated. The results showed that high bending stress was induced in the cable end near the deck, indicating that the cable-to-girder anchorage zone is the most vulnerable position under the close-in blast scenario. Parametric analyses were carried out to further investigate the effects of cable dimension, prestressing force, cable length, and anchorage angle on the dynamic response of the parallel wire cables. It was found that the cables with smaller dimensions and higher prestressing force are more vulnerable, while the cable length and anchorage angle have limited effects on the performance. The results could be used in the safety evaluation and preliminary protective design of cable-stayed bridges under potential blast threats.

BEHAVIOR OF PRE-STRESSED INTERSECTING CABLE STEEL BRIDGE

Cable-stayed bridges are known as one of the most effective and graceful forms of bridges. The main problem in the design of cable-stayed steel bridges is their deformability, especially under asymmetrical loads. Stabilization of the initial form of cable-stayed bridges can be achieved by selecting the appropriate cross-sectional area of the cables and their pre-stressing, as well as by increasing the cross-sectional height of the stiffness beam. However, a greater effect can be achieved by applying new forms of such bridges. Solutions for such bridges with an atypical arrangement of cables and additional pylons are already applied in practice. The article discusses an innovative pre-tensioned intersecting cable steel bridge structure system. The behavior of this bridge system under permanent and temporary loads is analyzed. Based on the performed numerical experiment, the efficiency of the innovative cable-stayed steel bridge system was determined. This newly designed bridge system is more effective in terms of stress and displacement distribution than a classic cable-stayed bridge system.

Reasonable completed state evaluation for hybrid cable-stayed suspension bridges: An analytical algorithm

Hybrid cable-stayed suspension bridges have broad application prospects due to their superior spanning ability, excellent overall stiffness, and economical efficiency, which outperform other long-span bridges. An analytical approach is proposed to determine the reasonable completed bridge state of hybrid cable-stayed suspension bridges in the paper. The specific steps are as follows: Firstly, the vertical supports offered by some stay cables and hangers in the main span to the main beam are estimated by assuming a continuous beam on multi-point rigid supports. For regions where both stay cables and hangers are used, the ratio of hanger force to the vertical force in the stay cable is assigned manually. Next, according to the assumption that the horizontal component force exerted by the main cables on both sides of the bridge tower and each pair of stay cables on the bridge tower are equal, the configuration and the internal force of the main cables and the stay cables are determined using the multi-segment catenary theory. The vertical forces exerted by the main and stay cables on the towers are summed up to estimate the axial force and strain acting at each position of the tower. In the side spans, the difference between the vertical support reaction in the continuous beam on multi-point rigid supports and the vertical force in the stay cable is used to calculate the weight of ballast of the main beam. The weight of ballast is apportioned as a uniformly distributed load acting on no more than three segments. The horizontal forces exerted by the stay cables on the main beam are summed up to estimate the axial force and strain acting at each position of the main beam. Finally, the analytical data of the full bridge are obtained as inputs of the finite element model. These data include the node coordinates and internal forces of the main cables, stay cables, towers, and the main beam. The calculation results obtained by the analytical method can be used for the preliminary design of hybrid cable-stayed suspension bridges. The proposed analytical algorithm can quickly solve the reasonable completed bridge state without complex adjustment of cable forces. It has the benefits of simplicity, high accuracy, and a clearly defined physical meaning. Finally, we verify the reasonability and effectiveness of the proposed analytical method in an asymmetric hybrid cable-stayed suspension bridge with a main span of 1400 m.

Structural Performance and Reasonable Cross-Ratio of Cross-Cable Multi-Tower Cable-Stayed Bridges

The Queensferry Crossing in the UK is the first multi-tower cable-stayed bridge in the world to use mid-span cross-stayed cables to improve structural rigidity. To study the structural performance and economy of cross-cable multi-tower cable-stayed bridges, a total of 11 finite element models were established using two cross-cable setting methods. By changing the number of crossed cables in the mid-span, the variation laws of structural deformation and internal force are obtained. The cross-cable efficiency based on structural stiffness and the cross-cable economy based on the consumption of cables used in the entire bridge are quantitatively analyzed, and it is considered that there is a reasonable cross-ratio of cross-cables. Combined with the current design specification and the empirical data of the actual bridge, the limits of the double indicators were determined, and a scheme comparison chart was formed. The results show that under the action of unbalanced load, the cross cable can greatly reduce deformation and balance the internal force of the structure. The optimal solution is to form a mid-span cable crossing by adjusting the cable spacing, and the reasonable range of cross-ratio is 15%~35%. If the structural stiffness is improved by adding additional cross cables, the cross-ratio should be controlled within 16% to ensure structural economy. This provides a reference for the design and research of cross-cable multi-tower cable-stayed bridges in the future.

Life-Cycle Cost Analysis of Long-Span CFRP Cable-Stayed Bridges

With the advantages of high strength, light weight, high corrosion and fatigue resistance, and low relaxation, carbon-fiber-reinforced polymer (CFRP) is an excellent cable material for cable-stayed bridges. However, the relatively high unit price of CFRP compared to that of steel may hinder the large-scale application of CFRP stay cables. This paper presents the economic comparison between long-span cable-stayed bridges using CFRP cables and the corresponding steel cable-stayed bridges through life-cycle cost analysis (LCCA). Three CFRP cable-stayed bridges with a main span of 600 m, 1200 m, and 1800 m, respectively, along with their steel counterparts, were designed, and their life-cycle costs (LCCs) were calculated. The comparison of LCCs was not only between the CFRP and steel cable-stayed bridges with the same span, but also between the cable-stayed bridges with different spans. Furthermore, the different unit prices of CFRP cables and different replacement frequencies of steel cables were also investigated. The results show that the initial design and construction cost of the long-span CFRP cable-stayed bridge is higher than that of the corresponding steel cable-stayed bridge, although using CFRP cables can reduce the materials used, primarily due to the higher unit price of the CFRP cable. Despite the higher initial cost, the long-span CFRP cable-stayed bridge can still achieve lower LCC than the steel cable-stayed bridge, because it has significantly lower rehabilitation cost and user cost, as well as slightly lower vulnerability cost. Furthermore, with the increase in the main span and the decrease in the unit price of CFRP cables, the LCC advantage of the long-span CFRP cable-stayed bridge becomes more obvious.

Survey Technology Design of Highway Cable-stayed Bridge

Survey Technology Design of Highway Cable-stayed Bridge

In-situ testing and model updating of a long-span cable-stayed railway bridge with hybrid girders subjected to a running train

This study investigates the dynamic responses of a long-span cable-stayed railway bridge with steel–concrete hybrid girders in different train load scenarios. The investigated scenarios included driving and braking of running trains. The bridge was instrumented with different types of sensors to measure strains, displacements, and accelerations during train load testing. Based on the measurement results, this study evaluated the effects of train speed on the vertical and transverse accelerations, impact factor, derailment coefficient, and wheel unloading rate, which are critical parameters that affect safety and riding comfort. Assessment results revealed that the bridge had adequate dynamic behavior to ensure safe operation and riding comfort of the train. Based on test data, a finite element model was developed, and a finite element model updating framework was proposed to improve the prediction accuracy. This study provides real-life test data and an assessment tool for promoting design and evaluation of cable-stayed railway bridges.