Single Pylon Cable-stayed Bridge Research Articles

A general data quality evaluation framework for dynamic response monitoring of long-span bridges

The structural health monitoring system (SHM) of long-span bridges inevitably produces low-quality data. It is important to evaluate the data quality and screen out normal data. Most existing studies on data anomaly detection have focused on abnormal data with abnormal waveforms in time domain. Usually there are pseudo-normal data in the SHM system, which seems normal in time domain. However, the pseudo-normal data of bridge dynamic responses may cause wrong dynamic characteristics identification. In this study, the existing data anomaly detection was further expanded to data quality evaluation, and both obvious abnormal and pseudo-normal data are evaluated. A general data quality evaluation framework for dynamic response monitoring of long-span bridge structures was proposed. The time–frequency characteristics of monitoring data were obtained by continuous wavelet transform, and the data quality was classified and evaluated by constructing and training a convolutional neural network (CNN). The proposed framework was verified by using acceleration monitoring data of a cable-stayed bridge. The results reveal that this framework solves the problem that CNN cannot detect pseudo-normal data through time-domain characteristics, and improves the accuracy of data quality evaluation by using time–frequency information of the monitoring data. The acceleration monitoring data of a suspension bridge and a single pylon cable-stayed bridge were used to demonstrate the feasibility of the cross-object application of the proposed framework. The evaluation accuracy for the acceleration data quality of the suspension bridge exceeded 96%. After the reinforced training of a small number of pseudo-normal data samples, the evaluation accuracy for the acceleration data quality of the cables of the cable-stayed bridge reached 96.8%. The framework shows a good generalization capacity and robustness in cross-object applications.

Study on the multi-criteria seismic mitigation optimization of a single pylon cable-stayed bridge across strike-slip fault rupture zones

Bridge structures across active faults suffer the serious threats from large surface deformation and velocity pulses. This study focuses on developing a multi-criteria optimizing method and investigating the damping effect of the optimized damper system on a cable-stayed bridge across a strike-slip fault. A simplified baseline corrected method is adopted to recover the static offsets in near-fault records and the improved record-decomposition incorporation method is modified to produce artificial across-fault ground motions. A single pylon cable-stayed bridge across a strike-slip fault is taken as the case bridge and the refined nonlinear numerical model is established in OpenSees. The conventional multi-criteria decision making (MCDM) theory is improved by introducing new function forms and a control parameter to assess the best fault-crossing angles of the case bridge. The improved MCDM method is integrated with the beetle antennae search algorithm to optimize the damper system of the case bridge. Finally, the influence of fault-crossing angles and earthquake parameters (permanent displacements and ratios of maximum to permanent displacement) on the damping effect of the optimized damper system are investigated. The results indicate that the cable-stayed bridge reaches optimal seismic performance when the fault-crossing angle is around 90° (75°-105°) as both the biaxial nonlinearity of the pylon and the risk of the girder unseating are reduced. The damper system is efficiently optimized by the proposed method, and the displacement and force demand of the case bridge are balanced. Both the fault-crossing angles and earthquake parameters are observed to have considerable influence on the damping effects. More specifically, the damping effect on most seismic responses is optimized when the fault-crossing angle approaches 90° (60°-120°). As the permanent displacement increases, the damping effect on the pier-girder relative displacement is significantly reduced and the damping effect on the pier moments is moderately decreased. Moreover, the damping effect is improved for all the seismic responses as the ratios of maximum to permanent displacements increase, with the exception of transverse displacement.

Analysis of tower foundation of long span single tower cable stayed bridge

The pylon is an important stressed structure in the single pylon cable-stayed bridge. The rationality of bearing platform and pile foundation of pylon foundation is one of the key research contents in the design of single pylon cable-stayed bridge. The main bridge of Tarim bridge in Xinjiang is a single tower double span cable-stayed bridge with span arrangement of (41 + 168 + 168 + 41) m and total height of cable tower of 125m. Arc shaped concrete tower columns are adopted. The stress of cable tower foundation is complex. The stress analysis of foundation scheme is one of the key problems of this project. In this paper, the geological conditions, structural stress, economic rationality, construction convenience and other factors are comprehensively considered, the different foundation types are compared and analyzed, the reasonable foundation type and layout type are determined, and the stress of the pile and cap structure of the main tower foundation is calculated and analyzed. Through the solid finite element model, this paper analyzes the influence of the stiffness deformation of pile cap on the stress of pile group foundation. The calculation results show that the stress of dumbbell shaped pile cap is more reasonable than that of rectangular foundation pile cap, and the number of pile foundation and the calculated pile length are reduced in varying degrees. By adjusting the pile foundation arrangement under dumbbell shaped foundation, the stress of pile foundation can be more uniform, which can be used as the foundation for similar projects. The foundation design provides reference and reference.

Optimization of cables size and prestressing force for a single pylon cable-stayed bridge with Jaya algorithm

In recent years, due to the many advantages cable-stayed bridges have often constructed in medium and long span. These advantages can be listed as an aesthetically pleasing appearance, economic and easy construction, etc. The main structural elements of cable-stayed bridges are listed as deck, pylon, cables and foundation. Perhaps one of the most vital and expensive of these structural elements is stay-cables. Stay-cables ensure the allowable displacement and distribution of bending moments along the bridge deck with prestressing force. Therefore the optimum design of the stay-cables and prestressing force are very important in achieving the performance expected from the cable-stayed bridges. This paper aims to obtain the stay-cables size and prestressing force optimization of the cable-stayed bridge. For this purpose, single pylon and fan type cable configuration Manavgat Cable-Stayed Bridge was selected as an example. The three dimensional (3D) finite element model (FEM) of the bridge was created with SAP2000. Analysis of the 3D FEM of the bridge was conducted under the different combined effects of the self-weight of the structural element, prestressing force of stay-cable and live load. Stay-cable stress and deck displacement were taken into account as constraints for the optimization problem. To optimize this existing bridge a metaheuristic algorithm named Jaya was used in the optimization process. 3D FEM of the selected bridge was repeatedly analyzed by using Open Applicable Programming Interface (OAPI) properties of SAP2000. To carry out the optimization process the developed program which integrates the Jaya algorithm and the required codes for calling SAP2000 is coded in MATLAB. At the end of the study, the total weight of the stay-cables was reduced more than 40% according to existing stay cables under loads taken into account.

Girder crack of concrete single pylon cable-stayed bridge

Taking the reinforcement and maintenance project of a concrete cable-stayed bridge as the background, aiming at the stress cracks on the web of the box girder of the main bridge after several years of operation, starting from the actual situation of design and construction, the integral calculation model of the bridge is established by Midas Civil and the local analysis and calculation model of the main girder is established by the general finite element software. Four kinds of analysis and calculation models are analyzed. Finally, it is shown that the web cracks of the bridge are caused by the cable tension when the bridge is cantilevered. On this basis, the concrete and feasible bonded steel plate method is proposed to repair and strengthen the cracks, which is of certain reference significance for the reinforcement and maintenance of the same type of bridge cracks in the future.

Seismic Response of Single Pylon Cable-Stayed Bridge under Scour Effect

Seismic Response of Single Pylon Cable-Stayed Bridge under Scour Effect

Seismic performance analysis of concrete-filled steel tubular single pylon cable-stayed bridge with swivel construction

For the cable-stayed bridge with swivel construction, due to the need of swivel construction, there is no consolidation between the bottom of the pier and the foundation during the construction process. Once an earthquake occurs, it is easy to cause the overturning of the bridge or the destruction of the bottom turntable. It can cause major safety incidents. In order to study the seismic safety of the single-pylon cable-stayed bridge in the swivel construction, it uses ANSYS finite element analysis software to establish a finite element analysis model for the construction stage of the single pylon cable-stayed bridge based on a certain project in this paper. Through the calculation and analysis of the single-pylon cable-stayed bridge with swivel construction under earthquake excitation, it is found that the locating pin at the center of the ball-end hinge has excessive shearing force under the 6-degree and 7-degree seismic excitation. It will cause the concrete around the pin to be crushed or even the ball joint to be destroyed. In view of the above problems, it proposes the seismic measures for arranging anchor rods at the edge of the turntable in this study, and calculates and compares the seismic effects of anchoring arrangements with different diameters and different inclination angles. It shows that the solution can significantly reduce the positioning pin shear force and prevent the upper structure from overturning under earthquake from results.

Nonlinear seismic response of a base isolated single pylon cable-stayed bridge

The vulnerability of single pylon cable-stayed bridges under strong ground motions are of great concern to both researchers and engineers. This paper investigates the seismic performance of reinforced concrete (RC) single pylon cable-stayed bridge equipped with friction sliding bearings under bi-directional earthquake excitations. Three-dimensional numerical models, consisting of the dynamic p-y elements, the fiber elements and the multi-layer shell elements, were developed in this study based on the prototype of a single pylon cable-stayed bridge in Guizhou Province, China, to investigate its seismic response. Three different types of friction sliding bearings were implemented between the base of the RC pier and the pile foundation to mitigate the dynamic response of the bridge superstructure under strong ground motions. The results of the nonlinear time history analyses indicate that friction sliding bearings can effectively reduce the base shear and the bending moment of the RC pier, as well as the seismic responses of substructure, at the cost of increasing the absolute displacement of the deck. To reduce the deck displacement, viscous dampers were implemented in parallel to the friction sliding bearings. Parametric studies and optimization analyses were performed on the critical parameters of the viscous dampers with the target of minimizing the absolute displacement of the deck and reducing the base shear of the RC pier to an acceptable level. The numerical results show that implementation of friction sliding bearings together with the viscous dampers is an effective seismic control approach to mitigate the seismic damage of the single pylon cable-stayed bridge.

Simplified seismic resistant design of base isolated single pylon cable-stayed bridge

The seismic vulnerability of single pylon cable-stayed bridges under strong ground motions in the transverse direction is of great concern to earthquake engineering researchers and bridge engineers. Introduction of base isolation to cable-stayed bridges has been proved very effective in reducing seismic forces in the bridges in previous studies. This paper proposes a direct displacement based seismic design (DDBD) procedure for base isolated cable-stayed bridge under transverse seismic excitation. One of the key aspects of the DDBD is the realization of a uniform transverse target displacement of the deck under seismic excitation, which is achieved by appropriate design of the isolator stiffness at the bottom of the pylon and the ends of the deck. The proposed DDBD procedure is applied in this paper to the seismic design of a single pylon cable-stayed bridge isolated by friction pendulum bearings. The effectiveness and the accuracy of the resulting design are checked by nonlinear time history analyses. The numerical results indicate that the proposed DDBD procedure can predict the deck displacement profile and amplitudes, as well as the base shear within a reasonable degree of accuracy. The case study demonstrates that the proposed DDBD procedure is sufficiently accurate and practical for the seismic design of base isolated single pylon cable-stayed bridges.

Experimental Study on the Steel-Concrete Composite Girder Joint of a Single Pylon Cable-Stayed Bridge

Hybrid girder cable-stayed bridges have been widely used around the world due to its advantages including the large-span viability of the main span with steel girder and the counterweight effect of the side span with concrete girder. The steel-concrete composite joint in hybrid girder cable-stayed bridges plays an important role in connecting the steel girder with the concrete girder and transferring the internal forces between two segments of different materials. Therefore, the performance and reliability of the composite joint is of great importance to such bridges. In order to examine the performance of the steel-concrete composite joint of a hybrid girder cable-stayed bridge with single pylon, a 1/4 scaled joint model was fabricated in the laboratory and static test was conducted. The stress distribution and the relative slip between concrete and steel under the combined action of axial force and bending moment were investigated. The test results showed that the maximum stresses of the steel and concrete components are within the allowable limits and the internal forces can be transferred smoothly between the steel girder and the concrete girder via the composite joint. The findings from this study provide useful reference and guidance for the design and testing of steel-concrete composite joints in hybrid girder cable-stayed bridges.

Analysis on Vertical Swivel Construction of Cable-Stayed Bridge with Steel Arch Pylon

Single pylon cable-stayed bridge with its attractive appearance , economical advantages, become more and more widely. Vertical swivel construction of cable-stayed bridge with steel arch pylon has just begun in recent years. Similar to the construction of Bridges are rare in our country,so many of the key technologies and construction techniques remains to be further research and improvement. This project is to Gaoxin second road single pylon cable-stayed bridge as the engineering background, to research the key technologies of vertical swivel construction.

Finite Element Modal Analysis of the Cable-Stayed Bridge

In the process of modeling, ignoring the displacement of the pier directly replaced with fixed constraint, beam elements were adopted to simulate girder and pylon, and link elements were adopted to simulate the cable. The first ten order natural vibration mode and natural frequency were obtained, and the dynamic characteristics analysis of a single pylon cable-stayed bridge was discussed, which can provide certain reference and guidance for solving the problem of the cable-stayed bridge design.

Method for Identifying Bridge Collapse Patterns: Analysis of Cases

AbstractA method is proposed to identify bridge collapse patterns based on the limit analysis theorem. The Erchong Floodway single-pylon cable-stayed bridge in Taiwan and the Kap Shui Mun twin-pylon cable-stayed bridge in Hong Kong were taken as examples. The bridge collapse patterns were identified, and the results were verified using nonlinear finite element analysis method. The simplified calculation method can correctly identify the damaged components that caused the total or partial collapse of the bridges. The calculation errors of the ultimate load-bearing capacity of the two bridges were less than 1.1% and 1.3%, respectively. Considering that the simplified method is accurate and computationally efficient, it can be used to study bridge collapse mechanisms to identify critical components and provide scientific foundation for bridge collapse-resistance design and reinforcement.

Static Analysis of Loading Properties of Small-Size Single-Pylon Cable-Stayed Bridge

This paper introduces the design of a small-size single-pylon cable-stayed bridge to be built in Xingtai city, China. The main structural members of this bridge including box-girder, stayed cables and pylon were selected to meet the requirement of bearing properties and artistic display. The numerical model for analyzing the static properties of the bridge structure was made by the design software MIDAS/Civil. The distribution and ultimate value of internal forces, stress and displacement of these main members are summarized, which provide the basis for calculating the reinforcement and prestressed strands of the bridge.

Huangpu Pearl River Bridge, China

The Huangpu Pearl River Bridge is a key project on the second ring highway of Guangzhou, which is the largest bridge in southern China. The total length of the bridge is 7049 m, including the northern approach bridge, northern channel bridge, central approach bridge, southern channel bridge and the southern approach bridges.The main bridge of the northern channel is a single pylon cable-stayed bridge with a main span of 383 m and steel box girder, which was constructed by balanced cantilever method. The main bridge of southern channel is a single span suspension bridge with a main span of 1108 m and steel box girder. This paper presents the tender design, the final design, the construction of the southern channel main bridge and the northern channel bridge including the foundation, pylon, main girder, main cable, main saddle and splay saddle.

Huangpu Pearl River Northern Channel Bridge, Guangzhou – the longest single‐pylon cable‐stayed bridge span in China

Huangpu Pearl River Northern Channel Bridge, Guangzhou – the longest single‐pylon cable‐stayed bridge span in China

Research on Construction Technology of Inclined Pylon of Single Pylon Cable-Stayed Bridge without Backstays

A new type of cable-stayed bridge, single pylon cable-stayed bridge without backstays is used in the Zhenshui Road Bridge in Xinmi City, China’s Henan Province, which adopts PC box girder with corrugated steel webs. It has many advantages such as light girder deadweight, low pylon height and avoiding webs longitudinal cracks. This novel bridge is adopted firstly in China. Cast-in-place method with bracket is used in the construction of the bridge’s inclined pylon because of its complex construction technology and tight construction period. In this paper, interests are focus on the scheme comparison and selection of bracket construction, the establishment of bracket’s computational model and the result of numeric analysis etc. The chief aim of this investigation was provides useful reference and enlightenment to similar bridge types.

Study on Seismic Performance of Single Pylon Cable-Stayed Bridge at High Intensity Seismic Region

Seismic design of long-span single pylon cable-stayed bridge at high intensity seismic region has been a difficult issue for designers. There is few references in this aspect at present. Based on the research achievements and the engineering background of a single pylon cable-stayed bridge at high intensity seismic region of East China, a full bridge model is established to analyze dynamic characteristics and seismic responses of the structure. According to the characteristics of excessive displacements of the pylons and main beams and greater plastic deformations of the pylons and the piers when the bridge is under strong earthquake, the damping effect of viscous dampers on the bridge is discussed. The results show that it is necessary to take measures to absorb seismic shocks. The results of this study can be as a reference for seismic design of similar bridges.

Analysis of Mechanical Behaviors of a Single Pylon Cable-Stayed and Continuous Rigid-Frame Composite Bridge

Xijiang River Bridge is the first hybrid railway bridge composed of single pylon cable-stayed and continuous rigid-frame system in China. To study the mechanical behaviors of the novel bridge, 3-D finite element model (FEM) based on Midas/Civil software is created; spatial effect of stayed cable is discussed; the self-vibration behavior of this unique bridge is analyzed by adopting the subspace iteration method; then by means of simulating analysis of the whole construction process, stress paths of critical parts in different construction stages are calculated and presented to study its mechanical behaviors. Results reveal that the composite bridge embodies features of both traditional cable-stayed bridge and rigid-frame bridge. Further study, however, shows that the unique hybrid system is mostly characterized by the rigid-frame type, meanwhile, as safety storage, the stay cable will play an important role in the “stiffness kept” of the whole structure, improving the actual stress and working condition of the whole structure in the long run.

Vulnerability assessment of single-pylon cable-stayed bridges using plastic limit analysis

Vulnerability of a structure hazards can be regarded as the study of its strength and robustness against damages caused by these hazards. Measures to quantify vulnerability of a structure provide an insight into its possible performance and help to identify critical components or damage locations that can lead to a catastrophic consequence. From structural viewpoint, one possible quantitative measure for structural vulnerability assessment is the ultimate load-carrying capacity. In this study, a technique based on the plastic limit analysis is proposed for the vulnerability assessment of single-pylon cable-stayed bridges. The limit analysis assumes that, for a steady-state collapse without an inertia effect, the power done by the external forces is dissipated by the yielding components. Hence the ultimate load-carrying capacity of a bridge can be calculated directly if a proper collapse pattern is assumed. Such a concept is illustrated by assuming plastic hinge models for the healthy and the damaged bridge. The technique is illustrated on a single-pylon cable-stayed bridge with two equal side spans of 200 m. Results show that the load-carrying capacities of both the healthy and the damaged bridges can be accurately determined using this technique. The proposed technique not only provides an efficient tool to assess the vulnerability of a single-pylon cable-stayed bridge but also can be used to study the effects of different design parameters on the load-carrying capacity and the vulnerability of cable-stayed bridges.