Hybrid Girder Cable-stayed Bridge Research Articles

Fatigue Performance of a Novel Steel–Concrete Joint of a Long-Span High-Speed Railway Hybrid Girder–Cable-Stayed Bridge

Fatigue Performance of a Novel Steel–Concrete Joint of a Long-Span High-Speed Railway Hybrid Girder–Cable-Stayed Bridge

Mechanical properties of an innovative steel–concrete joint for high-speed railway long-span hybrid girder cable-stayed bridges

This study investigates the mechanical properties of an innovative steel–concrete joint (SCJ) in a four-line long-span high-speed railway hybrid girder cable-stayed bridge with a main span of 672 m. Tests were conducted on a partial 3:8 scale model, supported by nonlinear finite element analysis (FEA), and the results of both were used to derive and validate mathematical formulae for bearing plate force transfer. The results revealed an uneven transverse distribution of stress in the SCJ, with a larger stress observed in the edge box. The non-uniformity coefficient λi is defined as the ratio of the absolute maximum stress to the transverse cross-sectional average at a given location, and λi,max of steel and concrete in the SCJ were 1.59 and 1.68, respectively. Drastic stress changes appeared in the bearing plate in the longitudinal direction. The maximum measured slip was relatively small, indicating that the steel and concrete in the SCJ functioned cooperatively. Concrete cracks observed in physical tests were mainly distributed in the edge box of the steel and concrete segments, revealing the superior force performance of the SCJ compared to the steel and concrete segments. The deformations of the SCJ changed elastically with an increasing load and satisfied Chinese standards. The bearing plate transferred approximately 59.92% of the axial force and dominated the force transfer. Formulae for the force transfer of the bearing plate were derived based on the stress characteristics of the innovative SCJ, revealing that, rather than its thickness, the bearing plate mainly relied on welds connecting the top and bottom plates and ribs to transfer force. Parameter analysis of the weld sizes of the bearing plate based on the derived formulae and FEA indicated that a reasonable thickness of the bearing plate is 38–60 mm, based on the matched weld sizes. The SCJ structure, the formulae for bearing plate force transfer, and the optimal bearing plate thickness can serve as valuable references during the initial design phase of SCJs.

Mechanical behaviour of steel-concrete joint in hybrid girder cable-stayed bridge

A steel-concrete joint section test model was constructed based on a mixed-scale ratio of the Lancang River hybrid girder cable-stayed bridge in Jinghong City, Yunnan Province. The internal forces and test loading values during normal operations were determined using finite element analysis. The performance was analysed by determining the mechanical indicators at key positions during the loading process. A finite element model of the test girder section was established to analyse the force transmission mechanism of the studied steel-concrete joint section. The test results showed that the centroid of the section moved upward during force transfer from the concrete to the steel girder. The relative slippage at the steel-concrete interface resulted in local unloading and an uneven distribution of longitudinal stresses in the crosswise direction. In addition, the cooperative bearing of the steel-concrete joint girder was transformed to a single bearing of the concrete girder, leading to a monotonic variation of stresses in the web plate. The simulation results showed that the surface plate force-sharing ratio of the composite bridge was the highest. In addition, the force-sharing ratios under the axial force and bending moment scenarios were 57.65% and 78.91%, respectively, indicating that the investigated steel-concrete joint demonstrated good stiffness transition stability. Furthermore, four force transfer types were identified in the steel-concrete joints. The research outcomes provide a fundamental basis for the rational design of joint components applied in hybrid girder cable-stayed bridges.

Research review on steel–concrete composite joint of railway hybrid girder cable-stayed bridges

PurposeThis 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.Design/methodology/approachBased 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.FindingsThe 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.Originality/valueThis 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.

Improved Metaheuristic Algorithm Based Finite Element Model Updating of a Hybrid Girder Cable-Stayed Railway Bridge

This study proposes a generally applicable improvement strategy for metaheuristic algorithms, improving the algorithm’s accuracy and local convergence in finite element (FE) model updating. Based on the idea of “survival of the fittest” in biological evolution, the improvement strategy introduces random crossover and mutation operators into metaheuristic algorithms to improve the accuracy and stability of the solution. The effectiveness of the improvement strategy with three typical metaheuristic algorithms was comprehensively tested by benchmark functions and numerical simulations of a space truss structure. Meanwhile, the initial FE model of a railway hybrid girder cable-stayed bridge was updated to examine the effect of the improved metaheuristic algorithm within the FE model, updating for complex engineering structures. The results show that the accuracy and stability of the improved metaheuristic algorithm were improved by this process. After the initial FE model of the hybrid girder cable-stayed bridge was updated, the calculated frequencies and displacements were closer to the measured values, better representing the actual structure, and showing that this process can be used for baseline FE models of bridges.

某独塔混合梁斜拉桥施工分析

某独塔混合梁斜拉桥施工分析

Analysis on steel-concrete joint section of hybrid girder cable-stayed bridge

Hybrid girder cable-stayed bridge has some advantages, such as structure mechanism performance and the low cost. In China, more and more cable-stayed bridge with hybrid girder appeared. The steel–concrete joint part is one of the key structures of large span cable-stayed bridge with hybrid girder, the static bearing capacity and fatigue performance of steel–concrete joint part structure is directly related to security and durability of the bridge. Through the finite element simulation calculation, the stress distribution is calculated, and the stress distribution of the steel structure top plate, steel structure baseplate, concrete top plate and concrete baseplate is analysed emphatically. Verify the bearing capacity and safety of the structural design of joint section.

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.

Structural Performance of a Hybrid Girder Cable-Stayed Bridge during Rotation Construction

The structure of hybrid girder cable-stayed bridges with single pylon and single cable plane is very complex, which leads to their complicated structural behavior and adds difficulties to their construction. Few studies have been conducted to investigate the structural performance of such bridges under rotation construction. In the present study, the structural performance of a hybrid girder cable-stayed bridge with single pylon and single cable plane during rotation construction is simulated with the Midas/Civil program. The deflection and the stress of the bridge girder and the deformation of the pylon at different construction stages during the rotation construction are investigated and are checked against the bridge design code. The camber for the bridge girder is also studied. The findings from this study provide useful reference for the design of such bridges for rotation construction and the control of the bridges during rotation construction.

Influence of Error of Unstressed Cable Length on Mechanical Behavior of Thousand-Meter-Scale Hybrid Girder Cable-Stayed Bridge

AbstractTaking Edong Yangtze River Bridge as the research subject, the influence of error of unstressed cable length on the geometric shape and internal force of super-span hybrid girder cable-stayed bridge during completion is studied on the basis of the geometry control method with full consideration of the structural nonlinear geometrical effect. Moreover, the mechanical behaviors of the center and side spans of the bridge and their control strategies are discussed. The analysis shows that structural differences between the center and side spans exerted an influence on the geometric shape and internal force. The influence of unstressed cable length error on the geometric shape in the center span of the completed bridge is greater than that of the side span, whereas the impact on internal force in the side span is greater than that in the center span. The mechanical behavior is relatively independent between span types. In addition, the percentage change of the girder stress reaches the maximum level in...

Research on the Equivalence and the Mechanical Performance of the Model of Steel-Concrete Joint

The hybrid girder cable-stayed bridge of railway has been applied in the design of the Yongjiang Bridge, it is first used in our country as yet. The mechanical performance of the steel-concrete joint as the key position of the hybrid girder cable-stayed bridge determine its safety and durability. Based on the background of a bridge in Zhejiang Province , the spatial finite-element model of model and actual bridge is developed to study the mechanical performance and verify the feasibility of design method of the model. As it turned out, the model can better reflect the stress of actual bridge. The trend of the stress of the key plates of its is basically identical. The steel-concrete joint can perfectly accomplish the transmission of the stress function. Bearing plate plays a vital role in the stress transfer, the function of the PBL shear connector near the bearing plate is obvious.

Dynamic Characteristics of Hybrid Girder Cable-Stayed Bridge

This paper is made after the dynamic test on Jing hang Channel Bridge in Wujiang, Jiangsu Province. Based on the test on this bridge, we get dynamic characteristics of the bridge span structure. We will analysis the vibration generated from the steel and concrete box girders of the bridge while the car is running on it. Based on the different characteristics of vibration from the two kinds of girders, we can analysis the influence of this hybrid girder on driving comfort.

Construction Technology of Jiu-Jiang Yangtze River Highway Bridge

Jiu-Jiang Yangtze River Highway Bridge, with a main span of 818m, is another long span hybrid girder cable-stayed bridge which connects Jiang Xi province and Hu Bei province in China. Steel box girder is adopted in main span and north side span, and main girder of south side span and south tower nearby is designed of concrete box girder. The pylon is concrete structure, with the height of 242.3m and H-shape. There are 216 cables used in this bridge, of which are assembled by parallel strands. Jiu-Jiang Yangtze River Highway Bridge began to construct in 2009, and was closed in December, 2012. The bridge opened to traffic officially in the next year. Design concept, construction method and vibration control measures about Jiu-Jiang Yangtze River Highway Bridge are introduced in this article.

Research on Load Transfer Mechanism of Steel-Concrete Joint Section of Hybrid Beam Cable-Stayed Bridge

The WuSu Bridge of HeiXiaZi Island is a hybrid girder cable-stayed bridge with one pylons and single cable plane. Based on the similarity principle, a 1:3 reduced scale test model of steel-concrete joint section was designed to study the load transfer mechanism and verify the rationality. The test model was loaded according to the serviceability limit state, and the stress distribution of control sections and main members were obtained. The finite element analysis on the test model was carried out and the load transfer mechanism was studied by the way of combining the test results and the FEA results. As shown in the results, the load from steel is smoothly delivered to concrete through steel-concrete joint section, and the load distribution of the components of steel-concrete joint section is rational. It is proved that the steel-concrete composite joint section is reasonably designed.

Analysis of Parameters' Sensitiveness of Long-Span Hybrid Girder Cable-Stayed Bridge

In order to improve the construction control precision of long-span hybrid girder cable-stayed bridge, the design parameters such as the weight of girder, the cable tensile force and the stiffness of cable are conducted sensitivity analysis through computing and comparing the influences of these parameters on the deflection of girders, the stress of girders and the cable force in the bridge's completion state. It was shown by the computation results that the main parameters of long-span hybrid girder cable-stayed bridge are the weight of girder and the cable tensile force, the stiffness of cable has a little influence on the completion state of the bridge. With this approach, through modifying the main parameters, while ignoring the influences of the secondary ones, the Jingyue Yangtze River Highway Bridge construction control has been successfully done. The test results show that the cable force and the contour of the bridge are in good state. They are both in the range of control, the relative error of the cable force is less than 3% and the elevation deviation is less than 5mm.

Experimental Study on Static Mechanical Behavior of Steel-Concrete Joint Section of Hybrid Girder Cable-Stayed Bridge

According to the structural characteristics of steel-concrete joint section of WuSu Bridge, a 1:3 reduced scale test model was designed to study the static mechanical behavior of the steel-concrete joint section. The test model is loaded according to the serviceability limit state and ultimate limit state separately, the stress of each members of the control sections of the test model is obtained. As shown in the results, the load from steel is smoothly delivered to concrete through the steel-concrete joint section, the stress values of the test model are generally less than the permissible value of the material given by the standard. The load-stress curve shows that the structural materials are in the elastic stage when being loading. All these show the steel-concrete joint section of WUSU Bridge has sufficient security reserve, the design of the steel-concrete joint section meets the security requirements. of the bridge is 140m+140m. The girder is consolidated with tower and pier. The main beam of the bridge is steel box beam with long cantilever while the beam at the tower root is made of concrete with two steel-concrete joint sections set up on both sides of main tower. Axial force, bending moment and torque from steel box beam are delivered to concrete beam through the bearing plate and the shear studs in steel-concrete joint section. The layout of the steel-concrete joint section of WuSu Bridge is shown in Fig. 1.

Preparation and Performances of Self-Compacting Concrete Used in the Joint Section between Steel and Concrete Box Girders of Edong Yangtze River Highway Bridge

The joint section between steel and concrete box girders is the key localization of the super-long span hybrid girder cable-stayed bridge in the Edong Yangtze River, a high strength self-compacting concrete (SCC) was required to use in the joint section. This paper systematically investigated the performances of three types of C55 grade self-compacting concretes (SCCs), such as plain SCC, micro-expansion and polypropylene fiber reinforced SCC and steel fiber reinforced SCC. The results indicated that the steel fiber reinforced SCC had the best workability and mechanical properties. The flexural toughness of the steel fiber reinforced SCC was much better than that of the other two types of concretes. The addition of steel fiber, or polypropylene fiber and expansive agent improved the crack resistance of SCC, and the micro-expansion and polypropylene fiber SCC reinforced had better crack resistance than steel fiber reinforced SCC. The three types of SCCs have very high chloride penetration resistance and advanced freezing and thawing resistance. Moreover, the test achievement of concrete casting technology for the full-scale model of steel girder chambers in the joint section is introduced. The steel fiber reinforced SCC was preferred to be used in the steel-concrete joint section.