Concrete-filled Steel Tube Arch Research Articles

A Study on the Ultimate Span of a Concrete-Filled Steel Tube Arch Bridge

In order to study the ultimate span of a concrete-filled steel tube (CFST) arch bridge, taking the structural strength, stiffness, and stability as the limiting conditions, the finite element analysis method is adopted to carry out research on the influence law of a single parameter of the pipe diameter, wall thickness, and cross-section height on the ultimate span of the arch axial shape. The result is used as a sample point to determine the ultimate span of the CFST arch bridge under multifactor coupling based on the response surface method. The finite element method is used to check the strength, stiffness, stability, number of segments and maximum lifting weight, steel content rate, and steel pipe concrete constraint effect coefficient of the CFST arch bridge under the ultimate span diameter. The results show that, when analyzed using a single parameter, the ultimate span diameter of the CFST arch bridge increases with the increase in the steel pipe diameter and the cross-section height, and then decreases. Moreover, it increases with the increase in the wall thickness of the steel pipe, and the CFST arch bridge reaches the ultimate span with the increase in the steel pipe wall thickness. When the pipe diameter is 1.38 m, the CFST arch bridge reaches the ultimate span; according to a multi-parameter coupling analysis, when the pipe diameter is 1.49 m, wall thickness is 37 mm, and cross-section height is 17 m, the CFST arch bridge reaches the ultimate span of 821 m, which meets all of the limiting conditions, and, at this point, the arch axial coefficient is 1.2. The results of the finite element calculation show that the structural strength, prior to the stiffness, stability, and other limitations, just reaches the critical value of the limiting conditions.

Cooling-excited infrared thermography for enhancing the detection of concrete filled steel tube interfacial debonding at concrete hydration

Interfacial Debonding occurring in concrete-filled steel Tube (CFST) arch bridges during construction is a critical issue, which can reduce the CFST carrying capacity and thus degrade the operational lifespan of the bridge. Timely detection of this type of defect during bridge construction can be highly cost-effective but rare sensing technology was reported for detection at this stage. Infrared thermography has been recognized as a potential detection method but still faces the challenge of low thermal contrast developed from concrete hydration. This research investigates the feasibility of using hydration heat as an internal heat source and proposes water-spray cooling as an external excitation to improve infrared debonding detection. The experimental study is carried out to investigate the detectability enhancement before and after the cooling excitation in terms of different debonding sizes and thicknesses. An image enhancement method is then proposed for debonding visualization based on the temperature difference matrix. In addition, the numerical simulation is conducted to analyze the cooling effect regarding the excitation intensity variation. The findings reveal that the thermal contrast of debonding ranges from 0.1 to 0.35℃ before cooling excitation and is enhanced by 2–3 times thereafter. In addition, the developed maximum thermal contrast of debonding can be characterized through a linear relationship to the cooling excitation intensity based on numerical analysis. The proposed method shows significant feasibility for early detection of debonding in CFST during arch bridge construction, which enables a new potential for structural inspection.

Shaking table test study on the seismic control of concrete-filled steel tube arch bridges based on dampers

Shaking table test study on the seismic control of concrete-filled steel tube arch bridges based on dampers

DNN surrogate model based cable force optimization for cantilever erection construction of large span arch bridge with concrete filled steel tube

Determining an ideal set of erection cable forces is crucial for concrete filled steel tube (CFST) arch bridges built using the cable-based cantilever erection method. As the span of these bridges increases, the intricacy and nonlinearity of their cable-based construction systems become more pronounced. For cable force optimization in such systems, the linear methods yield considerable inaccuracy, while the nonlinear methods based on the finite element model compromise on efficiency. To address this challenge, an erection cable force optimization method based on deep neural network (DNN) surrogate model is proposed. Firstly, the finite element model is utilized to generate force-alignment samples to depict the optimization problem. The mapping inherent in these force-alignment samples is learned by a DNN surrogate model to decouple the optimization process from the finite element analysis. Subsequently, random erection cable forces within plausible constraints are fed into the surrogate model to predict their corresponding arch rib alignments. The set of cable forces with an arch rib alignment closest to the target alignment is identified as the optimal result. Finally, the proposed method is applied to a 310 m span CFST arch bridge, and the maximum alignment error is limited within 11 mm.

Stayed Buckle Cable Recycling for Seismic Upgrading of Super-long-span Concrete Filled Steel Tube Arch Bridges

Stayed Buckle Cable Recycling for Seismic Upgrading of Super-long-span Concrete Filled Steel Tube Arch Bridges

Condition assessment of a concrete filled steel tube arch bridge using in-situ vibration measurements and an Improved Artificial Fish Swarm Algorithm

This study aims to assess the condition of a Concrete-Filled Steel Tube (CFST) arch bridge using in-situ vibration measurements, Finite Element Model Updating (FEMU) and an Improved Artificial Fish Swarm Algorithm (IAFSA). Dynamic coefficients, derailment coefficients and wheel unloading rates are extracted from the responses of running safety assessment. An updated finite element model using a kriging model and IAFSA is employed to evaluate the strength and rigidity of the structures. The results indicate that the natural frequencies and damping ratios of the CFST arch bridge meet the requirements of design code. The maximum bridge dynamic coefficient is found to be 1.085, indicating that the bridge dynamic performance is good. The wheel unloading rates of vehicle and locomotive exceed the specification limit, indicating that the track condition has to be improved before the bridge is operated. By updating an initial FE model, the errors between the predicted and the measured parameters are reduced to less than 5%.

A New Method for Correcting the Deviation of a Middle Pier Tower of a Long-Span Intermediate Arch Bridge

To control the deviation of a long-span concrete-filled steel tube (CFST) arch bridge during construction monitoring, a practical method for controlling tower deviation is studied and established. The form of construction of this bridge is an intermediate double-arch bridge, which differs from conventional bridges, thus requiring the urgent resolution of the issue of unbalanced middle piers. Therefore, the mechanical characteristics and construction process of an intermediate long-span, dual-coupled steel pipe arch bridge are meticulously examined by using a 1:10 scale model, with particular focus on discussing the deflection of the buckle tower during the installation of the arch rib segments. Construction control is implemented using a novel tower deflection control method that addresses unilateral torsion problems and difficulties in controlling the deflection of the tower. The model results are compared with the finite element analysis output, demonstrating that this new approach can resolve unbalanced tower deviations by maintaining absolute values within 0.5 mm. After correcting these deviations, the measured results from the model bridge tower align with the calculated analytical results and even surpass the theoretical expectations for tower deviation. This remarkable new method accurately resolves real-world bridge tower deviations.

Optimal Cable Force Adjustment for Long-Span Concrete-Filled Steel Tube Arch Bridges: Real-Time Correction and Reliable Results

For complex structures, the existing optimization method for suspender cable forces involves extensive matrix operations during the solution process, requiring high computational power and time. As a result, obtaining a more accurate solution becomes challenging. To address this issue and improve the stress distribution of suspenders in the completed state, while minimizing the need for frequent cable force adjustments and grid beam elevation changes during construction, a novel method for cable force optimization is proposed. In this study, the Pingnan Third Bridge, which is the world’s longest large span arch bridge with a span of 575 m, is taken as the engineering background. This study combines finite element analysis and multi-objective optimization methods to develop a cable force optimization approach for real-time correction during the panel girder lifting of long-span concrete-filled steel tube (CFST) arch bridges. The optimization method involves treating the panel girder weight and displacement during construction as parameter variables, and considering the displacement and unevenness of the panel girder in the completed state as constraint conditions. The objective equation is defined based on the displacement and cable force during the lifting construction process and, through optimization, the cable forces and displacements of each lifting section are calculated. The results demonstrate the feasibility of integrating optimization theory into the cable force optimization process during panel girder lifting. In this study, we have taken into account the characteristics of real-world engineering and focused on specific key points to reduce the order of the influence matrix. Consequently, the computational costs are reduced, facilitating the development of a multi-objective tension optimization program. By minimizing segment displacement variations and ensuring even cable force distribution in the completed state, the method ensures that the bridge meets the required completion requirements without the need for repetitive iterations or cumbersome calculations. It provides higher optimization efficiency and superior outcomes, offering significant value for cable force calculations during suspender construction of similar bridge types and guiding construction processes.

Study on progressive failure behavior and mechanical properties of tunnel arch support structures

Multi-layer composite support structure is widely applied in tunnel excavation but shows complicated failure behavior under rock pressure. Local joint broken, out-of-plane instability and arch-shotcrete interface slip widely exist and highly weaken the overall strength of support structure, which is inconsistent with the ideal assumption, leading to sever engineering disaster. Based on above situation, this paper adopts laboratory and numerical methods to investigate the bearing mechanism and failure behavior of arch joint, arch frame and arch-shotcrete composite lining. Then, a modified safety evaluation method of arch is proposed based on convergence-confinement method. The research results proved that, component strength and arch critical instability strength check are necessary in arch design. On the other hand, compared with thin-walled steel arch, the concrete-filled steel tube arch shows higher critical instability strength and better ductility, effective for controlling large deformation of soft rock. The research conclusions can provide reference for related tunnel design and construction.

Research on Optimal Arch Rib Inclination of Large Span Highway CFST through Arch Bridge

To investigate the reasonable range of the inclination angle of arch ribs, a spatial finite element method was employed based on a concrete-filled steel tube (CFST) basket-handle through an arch bridge with a span of 360 m. A spatial finite element model was established using Midas/Civil software, which was verified with actual bridge data. The effects of different arch rib inclination angles were investigated under static loads. The structural natural frequencies, linear elastic stability coefficients, internal forces, and displacements were comprehensively considered to determine the reasonable range of the inclination angle. The results show that when the inclination angle ranges between 8° and 10°, the first, third, and sixth natural frequencies of the structure are increased. It effectively improves the lateral and torsional stiffness of the arch ribs while ensuring optimal out-of-plane stability of the arch ribs. Compared with the parallel arch, the stability is improved by 20.2%. The effects of angle variation on displacement and internal force of the arch ribs were not significant. Considering all indicators, the optimal range of the inclination angle for the arch ribs of 300-m-level highway CFST arch bridges is suggested to be 8~10°.

Stress optimization analysis of long-span concrete-filled steel tube arch bridge based on Midas full-bridge finite element analysis model

CFST is a new building material developed on the basis of steel bars and concrete, which is frequently employed in bridge construction in China. The arch rib is the main stress part CFST arch bridge has a long span, and the safety of the arch rib directly determines the working performance of the whole bridge. Therefore, to better understand the stress of the arch bridge and ensure its safety of the bridge, the research employs the finite element program Midas to establish a long span concrete filled steel tube full bridge model and analyzes axial force, stress, and displacement of arch rib in each construction stage of the arch bridge. The results show that in different construction stages, the axial force on each section increases gradually. The upper and lower edges of the steel pipe are shown as a gradually increasing negative stress. The displacement change between each section is between (2–4) mm. To sum up, the finite element full bridge analysis based on Midas can accurately obtain the stress state of long-span bridges with CFST arcs. By using this technology, data from large-span CFST arch bridges may be efficiently employed in bridge optimum building, improving the load-bearing capabilities of the arch bridge.

Corrigendum: Calculation model of concrete-filled steel tube arch bridges based on the “arch effect”

Incorrect Author NameIn the published article, All author name was incorrectly written as Wang Shaorui, Li Yingbin*, Liu Zengwu, Cheng Tianlei. The correct spelling is Shaorui Wang, Yingbin Li *, Zengwu Liu, Tianlei Cheng. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.Incorrect Funding In the published article, there was an error in the Funding statement. Information about the source of funds was not added to the article. The correct Funding statement appears below.FUNDINGThis work was supported by Science and Technology Innovation Project of Chongqing Education Commission "Construction of Twin Cities Economic Circle in Chengdu-Chongqing Region" (KJCXZD2020032), Natural Science Foundation of Chongqing (cstc2021jcyj-msxm2491), Guangxi Key Research and Development Program (GuikeAB22036007-8), Chongqing Technology Innovation and Application Development Special Key Project (CSTB2022TIAD-KPX0205), This support is gratefully acknowledged. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.

A study on the dynamic instability of CFST arches with spatial curvature differences

With the rapid development of the construction technology of concrete-filled steel tube (CFST) arch bridges, the width-span and width-to-height ratios continue to increase, which cause stability problems, especially for the dynamic stability. The current Budiansky-Roth criterion (B-R criterion) and the energy criterion are hard to use and cannot be quantitatively described. Therefore, a CFST arch dynamic instability criterion by the difference in spatial curvature based on the changes in fiber strains is proposed in this paper. Firstly, the critical spatial curvature difference is derived based on the structural characteristics of CFST arches and is the threshold value of the dynamic stability discrimination. Then, the calculation format of the CFST arches’ dynamic instability criterion is established by the central difference method, and the calculation procedure is programmed. Furtherly, the accuracy of the proposed critical curvature difference method is validated by the instability-induced failure experiments. In addition, the discrimination results of instability-induced failure experiments are also obtained by B-R criterion as well as the energy criterion. The discrimination result of the proposed critical curvature difference method is consistent with those of B-R criterion and energy criterion. Moreover, the method proposed quantifies the critical load of dynamic instability into the threshold index by the critical curvature difference and has easy-to-measure parameters as well as easy to operate, which are more suitable for the engineering applications compared with other methods.

Calculation model of concrete-filled steel tube arch bridges based on the “arch effect”

In view of the limitations of the current code based on the equivalent beam-column method with the “rod mode” instead of the “arch mode” for the calculation of concrete-filled steel tube arch bridges, this paper takes the real bearing mechanism of the arch as the starting point and analyzes the different bearing mechanisms of the arch and eccentric pressurized column. The concrete-filled steel tube arch model test was carried out to analyze the deformation state and damage mode, and the geometric non-linear bending moment of the measured arch was compared with the bending moment value calculated by the eccentricity increase coefficient of the “rod mode.” The results showed that the transfer of internal force is from the axial force to the arch axis, causing the vertical reaction force and horizontal thrust. However, the eccentric compression column only produced the vertical force at the bottom and combines with the lateral deformation indirectly generated by the eccentric distance. In addition, the deformation stage of the arch is basically the same as that of the eccentric compression column. The final failure mode of the arch is 4-hinge damage, and the final failure mode of the eccentric compression column is single-hinge damage. The preliminary geometric non-linear bending moment value obtained by the two modes accords well. Therefore, the main factors for the difference in the bearing mechanism between the two modes are different force structures, force transmission routes, and sources of deformation. Due to the difference in the bearing mechanism, the final failure mode is different, and the deformation ability of the arch is weakened by using the “rod mode” instead of the “arch mode.” The geometric non-linear bending moment of the control section calculated by the eccentricity increase coefficient is conservative, but the influence of the geometric non-linearity of other sections is not considered enough.

Time history analysis of seismic response of through CFST non isolated and isolated arch bridges

To explore the difference in the impact of transverse bracing on the seismic effect of through concrete-filled steel tube arch bridges with non-isolated and earthquake-isolated, nine non-isolated and earthquake-isolated structural models under different cross-bracing arrangements were established, and Elcentro seismic waves were selected. The internal force, displacement, velocity, absolute acceleration, relative acceleration, and separation of arch ribs of each model were compared and analyzed under uniform excitation along the bridge, transverse and vertical directions, multi-dimensional combined excitation, and multipoint excitation considering the traveling wave effect. Based on the shear force and displacement of the earthquake support, it is concluded that the internal force response of different excitations of various models is more complicated. The installation of transverse bracing on the upper part of the arch rib can reduce the vertical displacement of the arch rib of the nonseismic structure. The “X”-shaped cross brace at the top of the arch rib and the “K”-shaped cross brace at the lower part help to reduce the transverse acceleration of the arch rib. The absolute acceleration and relative acceleration of the seismic structure arch ribs are significantly reduced.

Conceptual design of long span steel-UHPC composite network arch bridge

An innovative half-through network arch bridge with a main span of 470 m was proposed and designed using coarse aggregate ultra-high-performance concrete (CA-UHPC) and steel. To effectively resist the tremendous axial forces, we utilized circular hollow section arch ribs with a CA-UHPC outer layer and an inner steel tube in this proposal. To minimize the bending moment of the arch ribs, we arranged the inclined crossed hangers above the deck and similarly the columns below the deck, connecting the arch ribs with the main girder, and adopting a structural system of double-hinged arches. By incorporating the recently developed multi-material bi-directional evolutionary structural optimization method and through various parametric studies, we determined the best configuration for the bridge. We also used finite element analysis to investigate the corresponding structural responses. The numerical analysis demonstrates that the proposed bridge has excellent mechanical performance in terms of stability, overall structural stiffness, stress, and fatigue strength of each component. A comprehensive comparison between the proposed bridge and the more conventional concrete-filled steel tube (CFST) arch bridge under the same conditions reveals that: the construction-related CO2 emissions of the proposed bridge are significantly lower than those of the CFST bridge, while the economic indicators are slightly better. The proposed bridge is simpler, slenderer, and more elegant. Due to its innovative design, the proposed bridge can overcome a series of problems associated with conventional bridges such as the excessive self-weight of long-span concrete arch bridges, the challenges of welding thick steel plates on all-steel arch bridges and the high cost of these structures, as well as the disadvantages of CFST arch bridges.

Test of Broken Suspender Specimen and Equivalent Static Calculation Method for Half-Through and Through Concrete-Filled Steel Tubular Arch Bridges

In response to the frequent collapse of main girders caused by the breakage of suspenders on half-through and through arch bridges, a test specimen has been designed and fabricated with a through concrete-filled steel tube (CFST) arch bridge as the engineering background. A new electromagnetic disconnect trigger is employed to realize the rapid suspender breakage in the test specimen. Dynamic response tests of the residual structure of the arch bridge after suspender failures employing the test specimen have been carried out. A finite element model accounting for the suspender breakage dynamic process has been constructed by implementing ANSYS/LS-DYNA, and the results of the test and finite element analysis are compared. In order to simplify the dynamic response calculation process of the residual structure after hanger failures, the dynamic coefficient is introduced, and an equivalent static calculation method (ESCM) considering the dynamic effect of the suspender fracture is presented. Eleven kinds of CFST standard arch bridges with different spans are constructed, the static and dynamic effects of the standard arch bridge with various dynamic coefficients are compared, and then their corresponding dynamic coefficients for various suspender fractures are determined. The obtained results reveal that the proposed electromagnetic suspender breakage trigger can realize the hanger fracturing within 0.1 s, which accurately simulates the fracture process of an actual bridge suspender, and the influence on the value of the dynamic coefficient can be ignored when the duration for suspender fracture is less than or equal to 0.15 s. The influence of suspender fracture on the displacement and stress of the longitudinal beam is more notable than those of the arch rib. In particular, the long suspender breakage has the highest influence on the displacement and stress of the longitudinal beam and arch rib. The fracture of the second short suspender has a remarkable impact on the suspender force of the adjacent hanger. When the ESCM is utilized to assess the mechanical behavior of the half-through and through CFST arch bridge, the dynamic coefficients of the longitudinal beam (suspender) were evaluated to be, conservatively, 1.8 (1.8) and 1.8 (1.7), respectively.

Seismic Response Analysis of Multidimensional and Multiangle Long-Span Top-Supported CFST Arch Bridge

Taking a concrete-filled steel tube (CFST) arch bridge with a clear span of 400 m as an example, the in-depth analysis of its natural vibration characteristics is carried out by establishing a finite element model. Then, the three-dimensional El Centro recorded wave after amplitude modulation is taken as the excitation wave; the structural response under three kinds of single dimension and four kinds of multidimensional combined excitation and 0∼90° transformation X(longitudinal) + Y(transverse) orthogonal combined excitation is evaluated. The results show that the structure of long-span top-supported arch bridge extends in the longitudinal and vertical dimensions at the same time, and the mode shape density and mass distribution have multidirection and multiangle coupling. With the increase of excitation dimensions, the value and relative ratio of chord axial force increase. The maximum axial force ratio of X + Y to X and Y is 2.1, the maximum axial force ratio of X + Y + Z (longitudinal) to X + Y, X + Z, and Y + Z is 1.4, 1.8, and 1.8; the displacement in X and Y direction under combined excitation is independent and the displacement in Z direction is its coupling term, but the displacement under X + Y + Z combined excitation is only 10% larger than that under X + Z and Y + Z combined excitation. Under the combined excitation of X + Y with a changing angle of 0°∼90°, the axial force variation of the chord at different positions and on the same section of the arch rib has spatial characteristics. The variation range of upper and lower rod axial force varies from 0.63 to 1.35 and from 0.81 to 1.51, respectively, the change trend of displacement in the X and Y directions is relatively consistent, the change of displacement in the Z direction is asynchronous, and the displacement of vault section increases by one time. The seismic response of this bridge type under multidimensional and multiangle excitation shows obvious superposition.

Vehicle Load Spectrum and Fatigue Vehicle Model of a Long-Span Concrete-Filled Steel Tube (CFST) Arch Bridge Based on Measured Data of Weight-In-Motion System

Highway traffic load, speed, and volume have been increasing continuously over the years. Because of its special structural form, the fatigue problem of a long-span concrete-filled steel tube arch bridge becomes more and more serious. To research the vehicle load spectrum and fatigue vehicle model of a long-span concrete-filled steel tubular arch bridge, the traffic data of the arch bridge were collected using the weight-in-motion system. The vehicle type and vehicle load in the actual traffic flow have strong stochastic characteristics, which cannot be directly applied. Therefore, according to the measured data, 10 representative models are proposed to facilitate the classification and screening of vehicle data. The wheelbase, mass, axle load, and overload data of the representative vehicle types were analysed, and the axle load distribution characteristics of vehicles in different lanes were studied. It is found that the vehicle load is not uniformly distributed in different lanes but concentrated in one lane. Moreover, a vehicle load spectrum for the fatigue assessment of the long-span concrete-filled steel tubular arch bridge is proposed. Based on the fatigue damage equivalence principle, a fatigue vehicle model and a simplified fatigue vehicle model of bridge heavy-duty vehicles are proposed. Compared with the model in the AASHTO specification, it is found that the weight of the local fatigue vehicle load model is 15.1 t heavier than the vehicle model given in the specification. This study could be further referenced in bridge-fatigue life prediction, management and maintenance, etc.

Corrosion Fatigue Test and Performance Evaluation of High-Strength Steel Wires Based on the Suspender of a 11-Year-Old Concrete-Filled Steel Tube Arch Bridge

In this study, based on an actual project, the steel wire in the suspender of a concrete-filled steel tube arch bridge was selected from appropriate samples to perform acetic acid-accelerated salt spray tests, and steel wire samples with different corrosion degrees were obtained. A laser microscope was used to measure the roughness of the samples, and three corrosion samples were randomly selected from each group for grinding. Fatigue tests were performed on steel wire samples with different degrees of corrosion and polished steel wire samples, and the fatigue fracture was observed and analyzed. The results showed that few cracks on the steel wire surface could be eliminated by grinding, and the fatigue life of the specimens could be increased. Finally, the stress-life-mass loss rate (S-N-η) probability model based on the Weibull distribution was obtained using the measured fatigue data, which can be further referenced in the planning of the inspection of suspender service status, steel wire corrosion protection, and fatigue life prediction, etc.