Cable-stayed Structure Research Articles

Algorithm for determining tensions in a stay cable with a manufacturing defect

Purpose. Establishing the influence of presence of a longitudinal area, on which there is detachment of layers over a limited length of a composite orthotropic rope, on its stress-strain state. Research methodology. Development of a method for calculating the influence of presence of a longitudinal area, on which there is detachment of layers over a limited length of a composite orthotropic rope, on its stress-strain state by constructing and analytically solving a model of a stress-strain state of a composite tractive element, considering the conditions of interaction of a rope with a permanent structure using the methods of mechanics of layered composite materials with soft and hard layers. Findings. Analytical dependencies are obtained in a closed form, which allow determining a stress-strain state of a composite multi-layer rope with partial local detachment of a separate layer, considering the breakage of one reinforcing element. An algorithm for determining a stress-strain state of a composite multi-layer rope with partial detachment of a separate layer considering the breakage of one reinforcing element is established. Characteristics of a dependency of unevenness coefficients of load distribution in reinforcing elements, displacements and shear angle tangents on the ordinal number of a damaged cable in a presence of partial local detachment of a separate layer of a composite stay rope is established. Scientific novelty. Influence character of presence of a longitudinal area, on which there is detachment of layers over a limited length of a composite orthotropic rope, on its stress-strain state is established. A method of calculating the influence of presence of an area of detached layers in a rope on its stress-strain state is developed. Practical significance. Local detachment of layers is possible in a process of producing a composite multi-layer stay rope. The developed algorithm makes it possible to determine a stress-strain state of composite stay rope with local layer detachment. The known values of detachment allow implementing justified engineering solutions regarding the conditions of safe, temporary use of a composite rope in cable-stayed structure.

Research on Safety State Evaluation of Cable-Stayed Bridge Structures across the Sea

In response to the lack of relevant research on the health monitoring system and assessment of the structural safety status of a cable-stayed bridge across the sea, the real-time monitoring data was determined by the health monitoring system installed on the bridge structure. Strain and displacement data for the bridge structure were analyzed and processed. Based on operational research principles, a safety condition assessment of the Channel 1 Bridge was conducted using the Analytic Hierarchy Process (AHP). First, the reserve strength method is applied to determine the weight proportion of monitoring indicators such as strain and displacement. Secondly, the weight proportion of each monitoring indicator at different cross-sectional positions is determined. Then, the hierarchical division of the cable-stayed bridge structure is performed from the lowest layer, and the rating level of the Channel 1 Bridge structure is obtained using the variable weight synthesis method. This provides a basis for management decisions in the bridge maintenance department and serves as an example for future safety assessments of medium-span cable-stayed bridges over the sea.

Process monitoring and terminal verification of π–section girder cable-stayed bridge

PurposeIn this paper, taking a p-section girder cable-stayed bridge as an example, the construction monitoring and load test of the bridge are implemented.Design/methodology/approachIn order to ensure the safety of cable-stayed bridge structure in construction and achieve the internal force state of the completed bridge, the construction process is monitored for liner and stress of the p-section girder, construction error and safety state during construction. At the same time, to verify whether the bridge can meet the design requirements, the static and dynamic load tests are done.FindingsThe results of construction monitoring show that the stress state of the structure during construction is basically consistent with the theoretical calculation and design requirements. The final measured stress state of the structure is within the allowable range of the cable-stayed bridge, and the structural stress state is normal and meets the specification requirements. The load tests results show that the measured deflection of the midspan section of the main girder is less than the theoretical calculation value. The maximum deflection of the main girder is 48.03 mm, which is less than 54.25 mm of the theoretical value, indicating that the main girder has sufficient structural stiffness. Under the dynamic load test, the natural frequency of the three spans of the bridge is less than the theoretical frequency.Originality/valueThis study can provide important reference value for the construction and maintenance of similar p-section girder cable-stayed bridges.

Seismic Response of Cable-Stayed Spanning Pipeline Considering Medium-Pipeline Fluid–Solid Coupling Dynamic Effect

With the aim of determining the influence of the fluid–structure coupling dynamic effect of the oil and gas transmission medium and pipeline on the seismic response, an oil pipeline supported by a cable-stayed spanning structure was taken as the study object. Kinetic equations taking into account the action of oil and gas medium were studied, and a finite element model structure considering the additional-mass method and the fluid–structure coupling effect were established separately. In addition, the mechanism of the oil–gas–pipeline coupling action on the seismic response of pipeline structure was analyzed, and the results were obtained. The results show that the pipeline has a minimal seismic response at the abutment location, the seismic response gradually increases along the abutment to the main tower, and the seismic response reach is maximized at about one-fifth of the bridge platform. The seismic response of the oil and gas pipeline model structure using the additional-mass method is generally more significant than that based on the fluid–solid coupled dynamic model; moreover, the maximum displacement response differs by about 24%, and the maximum acceleration response differs by approximately 30%, indicating that the oil and gas medium has a certain viscoelastic damping effect on the seismic response of the oil pipeline, which provides a reference for the seismic response calculation theory and analysis method of cable-stayed spanning oil pipelines.

A universal algorithm for linear and quadratic programming in the problems of contact deformation of cable-stayed structures with one-way connections

Problems in production activities that require optimization problems are extremely numerous and very diverse. Optimization approaches are most often associated with the search for the best version of a structure or building. Mathematical methods for solving such problems are developing rapidly and are widely used. They actively and productively penetrate into many areas of scientific research, into engineering and design developments, are an important tool for improving design efficiency throughout the entire process of creating structures. The search for the best design solution is reduced to the selection of a set of parameters that provide a stationary value of the objective function. A wide range of extreme problems of practical orientation, as a rule, in mathematical models contains restrictions on design parameters of the equality-inequality type. In general, their set makes up the content of such a section of mathematics as Mathematical Programming. Due to the fact that there is no single solution method, diversity in research approaches has formed, which divides them into groups, classes, etc. Linear programming (LP), as one of the sections, with a linear objective function and constraints is well studied and successfully applied. Methods of solving problems of nonlinear programming, which includes quadratic programming, are more complex. Therefore, the development of convenient computational schemes is relevant. The essence of this work is that the statements of 2 optimization problems are formalized in a single and convenient form of a symmetric matrix dependence, which makes it possible to obtain an effective (in our opinion) algorithm for their implementation. Namely, a unified scheme for solving both LP and KP problems based on matrix algebra operations is proposed. Quadratic programming (QP), as the second section, also has wide possibilities, in particular, it allows considering the practical tasks of calculating VAT in the mechanics of a deformed solid body under the conditions of contact interaction. Such problems, in particular, include cable-stayed structures with one-way connections and span lengths that can reach tens or hundreds of meters. As an example, the behavior of a model cable-stayed span structure under varying wind loads is considered. The given results may be of interest.

Monitoring of the Queensferry Crossing, Scotland

The Queensferry Crossing opened in 2017 to enhance the resilience for road vehicles crossing the Firth of Forth outside Edinburgh, Scotland. The M90 carriageway consists of two lanes of traffic in each direction and hard shoulders. The three-tower, cable-stayed structure extends for 2.7 km, including approach viaducts. Structural health monitoring was specified by the employer in the construction works including 2184 physical sensors, which is believed to be the world's largest bridge monitoring system. This paper describes the monitoring and its uses thus far. A load test was conducted in 2020, comparing the sensor data favourably to the design. The monitoring is now integral to the operation of the bridge for measurement of structural performance and the management of the route. Automated reports give analysis of fixed periods of time and further detail for specific triggered events in occurrences of high load, abnormal load movements and extreme weather. The user interface includes a threshold alert system informing of the need for specific inspection and maintenance regimes. Route management in winter and extreme weather response is enhanced with the inclusion of sensor data. Monitoring data are also being used for research at various universities, each of which is described in brief.

An Improved Static Residual Force Algorithm and Its Application in Cable Damage Identification for Cable-Stayed Bridges

For cable-stayed bridges, cables are very important components to maintain the safety of the whole bridge structure. It is well-known that change in cable force reflects the health of the cable-stayed bridge. Therefore, it is necessary to detect and quantify local damage in cables prior to the occurrence of a failure. To this end, an improved residual force algorithm independent of static load vector was proposed in this study. The proposed method mainly makes use of the particularity that only a few coefficients in the residual force and static load vectors are nonzero. By combining two different static loading modes, a new damage indicator vector was defined in the method for damage localization and quantification. Compared with existing static residual force methods, the significant advantage of the proposed algorithm is that the specific value and loading position of the static load are not required in the damage identification process. This special advantage causes this method to not require special static loading, but instead uses any load vehicle. This advantage can make the operation process of structural damage identification based on static tests easier and faster. A single tower cable-stayed bridge structure was used to verify the feasibility of the proposed method in cable damage identification. It was shown that the proposed method successfully identified cable damage, even if the value and loading point of the static load were uncertain.

Digital modelling of a double-inclined-arch-pylon cable-stayed bridge in Beijing, China

Completed in 2019, the New Shougang Bridge in Beijing, China is an innovative double-inclined-arch-pylon cable-stayed structure with uniquely curved and twisted steel pylons. The 1354 m long, five-span steel road crossing carries eight lanes of traffic over the Yongding River to the west of the city. This paper describes the use of building information modelling to help design and construct the complex-shaped structure. Three-dimensional visual checks and virtual preassembly were carried out prior to construction, while laser scanning of as-built components was used to check accuracy and deflection.

Vertical Vibrations of Footbridges Due to Group Loading: Effect of Pedestrian–Structure Interaction

The vibration serviceability of footbridges has evolved from the adoption of a single pedestrian crossing in the resonance condition to load cases in which several pedestrians cross the structure simultaneously. However, in spite of this improvement, pedestrians continue to be considered as applied loads in codes of practice. Recent research has pointed out that modeling pedestrians as dynamic systems is a step further in the search for a more realistic design approach. This is explored in this paper, focusing on the case of vertical vibration. A two-span cable-stayed test structure was selected, and accelerations were measured from single and group crossings, both at the structure and at a pedestrian’s waist. Numerical simulations considering the pedestrians modeled as loads only and also as dynamic systems were implemented, and numerical and experimental time response vibration signatures were compared. Reductions of up to 25% and 20% in peak and RMS acceleration, respectively, were obtained when pedestrians were modeled as dynamic systems, in comparison with the less realistic model of pedestrians as loads only. Such reductions were shown to depend on the number of pedestrians involved in the group. The results, thus, highlight that pedestrian–structure interaction is an asset for the vibration serviceability design of footbridges.

The design of super long span pedestrian landscape cable stayed bridge with sightseeing bridge tower

According to the design requirements of the super long-span pedestrian landscape cable-stayed bridge in Lake view Park, a kind of sightseeing tower-style pedestrian landscape three-tower cable-stayed bridge structure system was proposed. Sightseeing tower type bridge tower structure and duck egg arched bridge tower replace traditional cable-stayed bridge tower structure. Through the establishment of Midas finite element analysis model, dynamic modal analysis research was carried out. The analysis shows that: the sightseeing tower structure and the cable-stayed bridge tower structure are combined into one, and the two have good structural matching.

Delivering a Masterpiece

The new Kosciuszko Bridge, also known as the K Bridge, is a twin-span, cable-stayed structure that traverses Newtown Creek, linking the New York City boroughs of Brooklyn and Queens via the Brooklyn–Queens Expressway, which runs east to west. Built in two phases, the eastbound bridge was completed in April 2017, and the westbound bridge was completed in August 2019. Both phases represent the first major bridge in New York City since the Verrazano–Narrows Bridge in 1964, and it is the state's first cable-stayed bridge.

Experimental and numerical study on cable breakage equivalent force in cable-stayed structures consisting of low-relaxation seven-wire steel strands

Investigation of a global structural dynamics model of a cable-stayed structure subjected to the cable breakage event requires the determination of the Cable Breakage Equivalent Force with respect to time [CBEF(t)]. The CBEF(t) is an applied axial force to the structure from the stay cable considered to break which is reduced from before the breakage to after the breakage. In this study, a generic CBEF(t) in cable-stayed structures consisting of low-relaxation seven-wire steel strands is obtained experimentally and numerically. The generic CBEF(t) can be introduced in a global structural dynamics model of a cable-stayed structure directly, without the need of a very detailed and costly model for the cable breakage. An experimental program was performed as representative of a stay cable, for which three different lengths of the 3/8-inch strand were tested. A full 3D finite element (FE) model was also developed in ABAQUS/Explicit in which, by a predefined imperfection, the breakage location corresponding to the experimental observation was assigned to the FE models of the 3/8-inch and 0.6-inch strands. The results reveal that the CBEF(t) is determined in two time intervals: a tensile rectangular force in the first and a compressive force in the second. Moreover, the breakage location affects the CBEF(t), while the CBEF(t) is independent of the total length of the unbroken strand, lubricating, and the interaction between the broken cable and the damaged cable-stayed structure. The comparison between wires shows that the main part of the CBEF(t) is related to a center wire. In the last part of this paper, a simplified and generic CBEF(t) is proposed which can be used for global dynamics models of all cable-stayed structures with 3/8-inch and 0.6-inch strands.

Design of Pre-stressed Cable Rod Radar Array Structure Based on Finite Element Analysis

In recent years, with the increasingly high requirements of radar thinness, the radar array appears thinner and thinner, which is easy to make the stiffness of the radar array is not enough, leading to serious deformation of the radar array, and thus affecting the work of the radar and the whole machine life. As a new type of space structure with light weight and high strength, the pre-stressed cable-stayed structure can play a good role in replacing the traditional front structure. According to the overall design requirements of a radar and the RMSE requirements for the plane flatness, the pre-stressed cable-stayed structure of the radar array is preliminarily designed, and the finite element analysis results are used to optimize the design and finally meet the design requirements.

Seismic Assessment of Footbridges under Spatial Variation of Earthquake Ground Motion (SVEGM): Experimental Testing and Finite Element Analyses.

In this paper, the seismic assessments of two footbridges, i.e., a single-span steel frame footbridge and a three-span cable-stayed structure, to the spatial variation of earthquake ground motion (SVEGM) are presented. A model of nonuniform kinematic excitation was used for the dynamic analyses of the footbridges. The influence of SVEGM on the dynamic performance of structures was assessed on both experimental and numerical ways. The comprehensive tests were planned and carried out on both structures. The investigation was divided into two parts: in situ experiment and numerical analyses. The first experimental part served for the validation of both the finite element (FE) modal models of structures and the theoretical model of nonuniform excitation as well as the appropriateness of the FE procedures used for dynamic analyses. First, the modal properties were validated. The differences between the numerical and the experimental natural frequencies, obtained using the operational modal analysis, were less than 10%. The comparison of the experimental and numerical mode shapes also proved a good agreement since the modal assurance criterion values were satisfactory for both structures. Secondly, nonuniform kinematic excitation was experimentally imposed using vibroseis tests. The apparent wave velocities, evaluated from the cross-correlation functions of the acceleration-time histories registered at two consecutive structures supports, equaled 203 and 214 m/s for both structures, respectively. Also, the coherence functions proved the similarity of the signals, especially for the frequency range 5 to 15 Hz. Then, artificial kinematic excitation was generated on the basis of the adopted model of nonuniform excitation. The obtained power spectral density functions of acceleration-time histories registered at all supports as well as the cross-spectral density functions between registered and artificial acceleration-time histories confirmed the strong similarity of the measured and artificial signals. Finally, the experimental and numerical assessments of the footbridges performance under the known dynamic excitation generated by the vibroseis were carried out. The FE models and procedures were positively validated by linking full-scale tests and numerical calculations. In the numerical part of the research, seismic analyses of the footbridges were conducted. The dynamic responses of structures to a representative seismic shock were calculated. Both the uniform and nonuniform models of excitation were applied to demonstrate and quantify the influence of SVEGM on the seismic assessment of footbridges. It occurred that SVEGM may generate non-conservative results in comparison with classic uniform seismic excitation. For the stiff steel frame footbridge the maximum dynamic response was obtained for the model of nonuniform excitation with the lowest wave velocity. Especially zones located closely to stiff frame nodes were significantly more disturbed. For the flexible cable-stayed footbridge, in case of nonuniform excitation, the dynamic response was enhanced only at the points located in the extreme spans and in the midspan closely to the pillars.

Numerical Simulation of Buffeting Response of Cable-stayed Truss Bridge with Unconventional Load in Port

Zhang, X.-T.; Chen, X.-J.; Wang, Q.; Li, P., and Zhou, H.-M., 2019. Numerical simulation of buffeting response of cable-stayed truss bridge with unconventional load in port. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 275–279. Coconut Creek (Florida), ISSN 0749-0208.Wind and waves seriously threaten the safety of structures in coastal ports. In this paper, the long-span cable-stayed truss structure in port for ore transportation along the coast is taken as the analysis object, with the static three-point force coefficient which obtained based on numerical wind tunnel simulation, the buffeting response of structure induced by turbulent wind load is studied by time-domain analysis method. The results show that the amplitude of buffeting response induced by turbulent wind load is larger than that of static wind load and it is also found that the increase of the main girder retaining wall and the operation load have great influence on the buffeting response of the structure. The research results can provide a strong theoretical basis for the design of the project and similar projects.

Design and construction of a launched cable-stayed bridge in China

Zhengbei Bridge is a key structure on the new Nongye Road in Zhengzhou, central China. Completed in 2019, it crosses the city’s north railway marshalling yard, the biggest in Asia. The main bridge is a cable-stayed structure with a single pylon and two 221 m spans. This paper describes the design and construction of the bridge, including the incremental launching of the steel–concrete composite main girder over temporary trestles between the railway tracks. To avoid disrupting rail operations the trestles were up to 92 m apart, so the 56 m launch nose was supplemented with a kingpost and cables.

THE PRELIMINARY DESIGN AND TECHNICAL-ECONOMIC EFFICIENCY OF THE TWO-LEVEL BRANCHED CABLE-STAYED BRIDGE

An innovative steel cable-stayed pedestrian bridge structure and the preliminary design methodology are provided in this article. The advantages and disadvantages of the bridge design are presented. The comparative analysis of the innovative steel cable-stayed pedestrian bridge structure and a similar structure of a single pylon fan cable-stayed bridge with an 80 m span is provided, the main criteria are reviewed and conclusions are formulated. The main features of the innovative branched cable-stayed bridge behaviour are reviewed. An overview of technical-economic efficiency and conclusions are presented.

Damage diagnosis in bridge structures using rotation influence line: Validation on a cable-stayed bridge

This study proposes a new damage identification technique for condition assessment of bridge structures. The method is based on the concept of rotation influence line (RIL) at the bridge bearing locations, and solely relies on measurements obtained from two points at either end of the bridge e.g., RILR and RILL. The sensitivity of the rotation measurement to damage is first investigated using a 1-D simply supported beam model and it is demonstrated that unlike conventional strain measurements, the rotation measurement is capable of providing useful information about damage even though it is far from the measurement point. Further, an existing cable-stayed bridge is considered to validate the capability of RIL in damage identification. A comprehensive three-dimensional finite element model (FEM) of the bridge is established and calibrated using the measured static and dynamic responses. Numerous field tests are conducted on this large-scale structure to extract static and dynamic characteristics, including natural frequencies, mode shapes and influence lines (ILs). Sixteen hypothetical damage scenarios are induced in the numerical model, including symmetric and asymmetric cases of cable loss. A damage index based on the normalised discrepancy of RIL between the benchmark state and an unknown state is introduced and through extensive investigations it is demonstrated that regardless of damage location, either RILR or RILL (or both) can successfully identify the induced damage in all of the sixteen damage scenarios. In contrast, the success of strain-based measurement is highly dependent on the closeness of damage to the sensor location, thus a much higher number of strain gauge sensors is required not to misidentify damage. The contribution of this work is four-fold. First, a novel and robust damage identification technique based on RIL is proposed which has not been reported in the literature. Second, the method solely relies on two measurement points e.g., two tilt meters at either end of the bridge and it is capable of identifying damage, even far from the sensor location. Third, the validation of the technique is demonstrated through extensive numerical and field test investigations on a statically indeterminate cable-stayed bridge structure. Finally, it is demonstrated that the conventional strain-based measurement is very likely to misidentify cable damage even with extreme case of cable loss.

Fatigue Assessment of a Slender Footbridge Based on an Updated Finite Element Model

Finite element model updating is a well-known technique to better characterize the real behaviour of civil engineering structures. The updated numerical model can be used to perform a more accurate structural assessment. Herein, its effectiveness is validated through the fatigue assessment of a lively footbridge considering two different numerical models: (i) a preliminary finite element (FE) model and (ii) an updated version of the preliminary model based on the modal parameters of the footbridge identified experimentally. For this purpose, the Malecon footbridge (Murcia, Spain) has been considered. This footbridge, a cable-stayed structure, is prone to vibrate in vertical direction under continuous walking pedestrian flows so fatigue damage might be expected on its supporting cables. A detailed FE model of the footbridge has been performed and subsequently updated based on the experimental modal parameters of the structure. The behaviour of the pedestrian flows was characterized by field observations. Finally, a comparison is performed between the fatigue damage of some cables of the footbridge considering the two mentioned FE models. The safe life method was used to assess such damage. As result, a maximum relative difference around 52 % was obtained between the two numerical models.

Nonlinear dynamic analysis of cable-stayed arches under primary resonance of cables

In this paper, the one-to-one interaction of a cable-stayed arch structure under the cable’s primary resonance is investigated. Based on the coupling condition at the arch tip, the partial differential equations governing the planar motion of the system are derived using the extended Hamiltonian principle, while with the application of the Galerkin method, these equations are transformed into a set of ordinary equations. Applying the method of multiple scales to these ordinary equations, the first approximated solutions and solvability condition are obtained. The one-to-one interaction between the cable and the arch is investigated under simultaneous internal and external resonances for an actual cable-stayed arch structure. Based on the shooting method and the pseudo-arclength algorithm, the dynamic solutions of the system are obtained, and a period-doubling route to chaos is analyzed. The effects of the cable’s initial tension, inclination angle, the arch’s rise-to-span ratio and intersection angle between the cable and the arch are explored, and the results show that the interaction response mainly depends on specific parameters.