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The purpose of this paper is to provide a variety of viewpoints to illustrate the mechanism of the deck-stay interaction with the appropriate initial shapes of cable-stayed bridges, which is validated by a symmetrical structure.

Based on the smooth and convergent bridge shapes obtained by the initial shape analysis, the one-element cable system (OECS) and multi-element cable system (MECS) models of the symmetric harp cable-stayed bridge are developed to verify the applicability of the analytical model and numerical formulation from the field observations in the authors’ previous work. For this purpose, the modal analyses of the two finite element models are conducted to calculate the natural frequency and normalized mode shape of the individual modes of the bridge. The modal coupling assessment is also performed to obtain the generalized mass ratios among the structural components for each mode of the bridge.

The findings indicate that the coupled modes are attributed to the frequency loci veering and mode localization when the “pure” deck-tower frequency and the “pure” stay cable frequency approach one another, implying that the mode shapes of such coupled modes are simply different from those of the deck-tower system or stay cables alone. The distribution of the generalized mass ratios between the deck-tower system and stay cables are useful indices for quantitatively assessing the degree of coupling for each mode. For each identical group of stay cables in the MECS model, the local modes with similar natural frequencies and normalized mode shapes consist of the participation of one or more stay cables. These results are demonstrated to fully understand the mechanism of the deck-stay interaction with the appropriate initial shapes of cable-stayed bridges.

It is important to investigate the deck-stay interaction with the appropriate initial shape of a cable-stayed bridge. This is because such initial shape not only reasonably provides the geometric configuration as well as the prestress distribution of the bridge under the weight of the deck-tower system and the pretension forces in the stay cables, but also definitely ensures the satisfaction of the relations for the equilibrium conditions, boundary conditions and architectural design requirements. However, few researchers have studied the deck-stay interaction considering the initial shape effect. The objective of this paper is to fully understand the mechanism of the deck-stay interaction with the appropriate initial shapes of cable-stayed bridges, which is validated by a symmetrical structure. The modal coupling assessment is also performed for quantitatively assessing the degree of coupling for each mode of the bridge.

The existing methods for determining cable forces in cable‐stayed bridges constructed are based on assumption of complete determinacy of structural parameters. This is usually referred to as deterministic analysis. But in reality there are uncertainties in design variables. These uncertainties include geometric properties (cross‐sectional properties and dimensions), material mechanical properties (modulus and strength, etc), load magnitude and distribution, etc. Thus deterministic analysis cannot provide complete information regarding cable forces in cable‐stayed bridges constructed. The purpose of this paper is to determine cable forces in cable‐stayed bridges constructed under parametric uncertainty.

An efficient and accurate algorithm is proposed to determine the cable forces in cable‐stayed bridges constructed under parameter uncertainty. The proposed method is a hybrid method, consisting of the improved Monte Carlo simulation method and forward process analysis method.

The proposed algorithm can obtain more information about the cable forces at different construction stages than the commonly used deterministic method, and it provides an improved understanding of the cable forces in cable‐stayed bridges constructed with parameter uncertainties.

The values of this type of research are that: it developed an efficient and accurate algorithm for determining the cable forces in cable‐stayed bridges constructed under parameter uncertainty; and it provided an improved understanding of the cable forces in cable‐stayed bridges constructed with parameter uncertainties.

In this paper, taking a p-section girder cable-stayed bridge as an example, the construction monitoring and load test of the bridge are implemented.

In 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.

The 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.

This study can provide important reference value for the construction and maintenance of similar p-section girder cable-stayed bridges.

This study aims to research the development trend, research status, research results and existing problems of the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge.

Based on the investigation and analysis of the development history, structure form, structural parameters, stress characteristics, shear connector stress state, force transmission mechanism, and fatigue performance, aiming at the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge, the development trend, research status, research results and existing problems are expounded.

The shear-compression composite joint has become the main form in practice, featuring shortened length and simplified structure. The length of composite joints between 1.5 and 3.0 m has no significant effect on the stress and force transmission laws of the main girder. The reasonable thickness of the bearing plate is 40–70 mm. The calculation theory and simplified calculation formula of the overall bearing capacity, the nonuniformity and distribution laws of the shear connector, the force transferring ratio of steel and concrete components, the fatigue failure mechanism and structural parameters effects are the focus of the research study.

This study puts forward some suggestions and prospects for the structural design and theoretical research of the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge.

In order to replace the conventional human maintenance of cable‐stayed bridges, a robot is designed and constructed for tasks such as cleaning, painting and rust‐detecting.

Adopting a modular approach, two kinds of climbing mechanisms, plus a painting mechanism and a rust‐detecting method are designed.

A robot that can climb and maintain the cables of cable‐stayed bridges has been designed and constructed. It has been proved by experiment that the robot can overcome many disadvantages of conventional human bridge‐maintenance, and drastically improve efficiency, cost, and safety.

The robot is of industrial size, but a new mechanism requiring less installing time will be designed for the future.

The robot has been applied to cables of the Nanpu Bridge and Xupu Bridge in Shanghai. More than 80 cable‐stayed bridges and six suspension bridges have been built or are being constructed across large rivers in China alone. This gives an enormous potential market.

The cable maintenance robot developed in this paper is the world's first special robot for the cables of cable‐stayed bridges.

Over-limit transportation has the characteristics of large axle load, large number of axles and lateral distribution width. Under the action of over-limit load, the coupling vibration effect of vehicle–bridge is more obvious, and the deformation of bridge components is large. Thus, research and analysis of the vehicle–bridge coupling dynamic response of long-span bridges under over-limit transportation has practical engineering significance.

Based on the principle of invariable elastic potential energy, this paper derives dynamic model of over-limit transportation n-axis flat vehicle. The numerical simulation method is used to model and calculate a cable-stayed bridge, and the static effect of the cable-stayed bridge and the dynamic response of vehicle–bridge coupling under different parameters are compared and analyzed.

The focus is on the influence of vehicle load and vehicle velocity parameters on the stress and amplitude of different cables under over-limit transportation, and the corresponding variation law is obtained.

The research on the coupled dynamic response of cable-stayed bridges has attracted the attention of many scholars, but there are relatively few studies on the coupled vibration of out-limit vehicles and bridges. In this paper, based on finite element software, a vehicle–bridge coupling model under bulk transportation is established.

Due to the deformation between the pylon and the girder caused by single tension of cables, the previously tensioned steel strands have stress relaxation, resulting in the actual cable forces being less than the design cable forces. To compensate the stress loss caused by the single tension of cables, this paper aims to present a practical compensation algorithm of stress relaxation during the construction period.

From the perspective of the essential cause of the stress relaxation, finite element analysis is used to solve the tension control force of each steel strand after a rigorous theoretical formula derivation.

The deformation and tension control force of each steel strand decrease with the advance of the tension sequence, and the decline rate drops gradually. However, the calculated force values of the steel strand are in good agreement with the measured value as the cable length decreases.

The previous rough calculation methods for the tension force of steel strands cannot meet the accuracy, and the accurate calculation methods often include the solution of nonlinear equations, which complicate the calculating process. Otherwise, there are few studies on the compensation of stress loss by calculating the deformation of the steel strand during the tension process. So, it developed an accurate and efficient algorithm to determine the tension control forces.

Owing to the cable flexibility, it is practically a lot easier to measure the high‐vibration frequencies of the cable than the fundamental vibration frequency. The objective of this study is to present a method to determine the cable tension based on frequency differences so that the effects of cable sag and bending stiffness can be included.

The paper includes theoretical derivation, laboratory study to verify the method and practical application in a real bridge.

It is suggested to measure the high‐vibration frequencies, and to use the vibration frequency difference to determine the fundamental vibration frequency of the cable and then to estimate the cable tension. The reliability of the method is verified by laboratory tests and the method is then applied to determine cable tensions in a real bridge.

This paper provides theoretical derivations to demonstrate that under certain conditions, the frequency difference of a cable with sag and bending is almost equal to the natural frequency of the same cable when it is taut. This unique characteristic of cable vibration is used to determine the cable tension similar to the fundamental frequency‐based taut‐string formula that is commonly used in practice.

The purpose of this paper is to analyze the cable-supported bridges more efficiently by building the finite element model with the spatial combined cable element.

The spatial combined cable element with rigid arms and elastic segments was derived. By using the analytical solution of the elastic catenary to establish the flexibility matrix at the end of the cable segment and adding it to the flexibility matrix at the ends of the two elastic segments, the flexibility matrix at the end of the cable body is obtained. Then the stiffness matrix of the cable body is established and the end force vector of cable body is given. Using the displacement transformation relationship between the two ends of the rigid arm, the stiffness matrix of the combined cable element is derived. By assigning zero to the length of the elastic segment(s) or/and the rigid arm(s), many subdivisions of the combined cable element can be obtained, even the elastic catenary element.

The examples in this field and specially designed examples proved the correctness of the proposed spatial combined cable element.

The combined cable element proposed in this study can be used for the design and analysis of cable-stayed bridges. Case studies show that it is able to simulate cable accurately and could also be used to simulate the suspenders in arch bridges as well in suspension bridges.

Field robots can surmount or avoid some obstacles when operating on rough ground. However, cable-climbing robots can only surmount obstacles because their moving path is completely restricted along the cables. This paper aims to analyse the dynamic obstacle-surmounting models for the driving and driven wheels of the climbing mechanism, and design a mechanical structure for a bilateral-wheeled cable-climbing robot to improve the obstacle crossing capability.

A mechanical structure of the bilateral-wheeled cable-climbing robot is designed in this paper. Then, the kinematic and dynamic obstacle-surmounting of the driven and driving wheels are investigated through static-dynamic analysis and Lagrangian mechanical analysis, respectively. The climbing and obstacle-surmounting experiments are carried out to improve the obstacle crossing capability. The required motion curve, speed and driving moment of the robot during obstacle-surmounting are generated from the experiments results.

The presented method offers a solution for dynamic obstacle-surmounting analysis of a bilateral-wheeled cable-climbing robot. The simulation, laboratory testing and field experimental results prove that the climbing capability of the robot is near-constant on cables with diameters between 60 and 205 mm.

The dynamic analysis method presented in this paper is found to be applicable to rod structures with large obstacles and improved the stability of the robot at high altitude. Simulations and experiments are also conducted for performance evaluation.