Curved Girder Bridge Research Articles

Influence of ground motion parameters on seismic response of a large-longitudinal-slope and small-radius curved girder bridge.

The mechanical performance of curved bridges under the action of an earthquake is complex. To obtain the influence of seismic parameters on the seismic response of curved girder bridges, this paper relies on a large slope small-radius curved steel box girder bridge (LSCGB) and selects seismic wave incidence angle, vertical component of ground motion, and site category as seismic parameters to carry out nonlinear time history analysis. Based on the analysis results of the case bridge, it is shown that the torsional vibration of the first 10 modes of LSCGB is significant, the modes are dispersed, and the contribution of high-order modes of vibration cannot be ignored. The most unfavorable seismic wave incidence angle is in the direction of 45°∼60° counterclockwise Angle from the central connection line of Pier No. 1 and Pier No. 4 of the bridge. The seismic response of the curved bridge components increases with the vertical seismic intensity, and the influence on displacement responses is more significant. The basic vibration period of curved girder bridges built on soft soil sites is extended by approximately 18.23%, and the seismic response of key components increases with the softening of the site soil. Therefore, when analyzing the seismic response of LSCGBs, the influence of vertical component of ground motion and site category should not be ignored.

Study on Vehicle-Bridge Coupled Vibration of Curved Girder Bridges under Different Road Surface Grades

This study explores the impact of different levels of road surface smoothness on the dynamic response of bridges. By conducting a detailed analysis under five different conditions of road surface smoothness, the mechanisms by which road surface irregularities affect the dynamic characteristics and safety performance of bridge structures are revealed. The research employs the finite element simulation method to compare and analyze the changes in key dynamic indicators such as vertical displacement, torsional angle, torque, and bending moment of bridges under different grades of road surface smoothness. The results indicate that a decrease in road surface smoothness significantly increases the dynamic response of bridges. The findings provide important reference information for bridge engineers in the design and maintenance of bridges.

Analysis of Vehicle-Bridge Coupling Vibration Characteristics of Curved Girder Bridges

When vehicles move on a bridge, the coupling effect between vehicles and bridges can affect driving safety and comfort, especially for curved bridges, therefore, choosing reasonable design parameters for curved bridges is crucial. In this article, a three-span curved continuous box-girder bridge was taken as the research object; the entire process of vehicle-bridge coupling vibration of highway curved girder bridges was conducted via numerical simulation and the vehicle-bridge coupling vibration analysis program Cmck 1.0 was developed. Then, the influence factors such as curvature radius, constraint mode, and vehicle characteristics on the vehicle-bridge coupling vibration of curved girder bridges were explored. The results showed that as the curvature radius increased, the dynamic response of the bridge offered a gradually decreasing trend and compared to the vertical dynamic response, the torsional response was more sensitive to the influence of the curvature radius. Different constraint methods significantly impacted the dynamic response of bridges, and the vertical and torsional dynamic responses of bridges under general constraint arrangement of straight bridges were increased compared to those under boundary conditions for curved beam bridges. As the axle load of the car decreases, the bridge mid-span vertical and torsional dynamic responses showed a decreasing trend. In contrast, the lateral dynamic response gradually increased.

Impact of Variable Parameters of Expansion Joints and Bearing Supports on the Vehicle-Induced Vibration of Curved Girder Bridges

To study how varying the parameters of expansion joints and bearing supports (E-B parameters) affects the dynamic response of a coupled vehicle–bridge system for curved girder bridges, a dynamic response analysis method for the coupled vehicle–joint (bearing)–bridge system, which takes into account centrifugal forces, was proposed and verified. Subsequently, taking a continuous curved box girder bridge as the prototype, the influence of the E-B parameters on the vehicle-induced dynamic response of the curved girder bridge was explored. The results showed that the dynamic amplification factor (DAF) of the middle beam of the expansion joint (DAF-EJ) and the main girder of the curved bridge (DAF-MG) were both significantly influenced by the E-B parameters. When there were height differences between the middle beam and side beam in the EJ, the DAF-EJ obviously varied, and the DAF-MG increased. When the EJ was damaged, the impact effect of the vehicle on the bearing support increased. The DAF-EJ and DAF-MG both increased with the decrease of the vertical support stiffness of the bearing support. The DAF-EJ was greatly affected by the single-support void at the near-slit end of the lane. The DAF-MGs at the beam end, the 1/4 point and 1/2 point of the first span, and the 1/2 point of the second span, were significantly affected by the single-support void near the measuring point. Compared with the single-support void, the DAF-EJ and DAF-MG more significantly increased under the double-support void. Variation in the height difference of the EJ had a more significant effect on the DAF-EJ and DAF-MG at the beam end, while a vertical stiffness reduction in the bearing support had a more significant effect on the DAF-MG.

Torsional behavior of curved concrete box beam with small radius

Curved concrete box beams are commonly used for their superior integrality performance and greater torsional stiffness. This paper investigates the torsional behavior of these beams using both experimental and finite element analyses. The experiment is based on a 1:6 scale model of a three-span curved girder bridge with a small radius. The study examines six different load cases, including central vertical and eccentric vertical loads. The study reports the detailed reaction forces of the supports, as well as the displacements and strains of the mid-span section. Finite element models are established to analyze the warping behavior of the curved concrete box beams. Based on the experimental and FEM analysis, the following conclusions are noted. Firstly, in the central load case, the strain of the curved concrete box girder is close to a straight line, so the curved concrete box girders follows the plane-section assumption. Besides, the warping normal stress is produced in curved concrete box girder in eccentric load cases. Moreover, the ratio of warping normal stress to bending normal stress is smaller and smoother in the section with diaphragms than that without diaphragms. And this ratio decreases with an increase in the curvature radius and diaphragm number. This study contributes to the theoretical and numerical modeling of a large span curved girder bridge with a small radius.

Analytical method for overturning risk assessment of curved girder bridges with single-column piers under heavy-duty vehicles

Overload-induced overturning of curved girder bridges with single-column piers occurs frequently, resulting in serious casualties and public property losses. Hence, it is essential to study the overturning mechanism of such bridges for an accurate overturning risk assessment. In this study, the dead loads of the bridge were first obtained considering the additional torque induced by the difference between internal and external self-weight, and the heavy vehicles-induced live loads were achieved accurately with the introduction of the trailer turning model. The mechanical model of the curved girder bridges with single-column piers was established, and analytical formulae of support reaction and torque considering bearing stiffness were derived based on the force method principle. Second, the assessment methods of the bearing disengagement state with combined support reaction force and torsion angle and overturning limit state with rotation of combined rigid body and deformation body were proposed, respectively. On this basis, the overturning risk assessment method of curved girder bridges with single-column piers was established for the two critical states. Finally, the entire overturning process of an example bridge was analyzed based on a finite solid element model, and the validity of the overturning risk assessment method was determined with the comparison of the evaluation results under critical loads.

Seismic performance of continuous curved girder bridge with high pier in Maduo earthquake and characteristic analysis

PurposeThe purpose of this study is to explore the seismic damage mechanism of the Dayemaling Bridge during the Maduo earthquake and discuss the seismic damage characteristics of the high-pier curved girder bridge.Design/methodology/approachIn this study, the numerical simulation method is used to analyze the seismic response using synthetic near-field ground motion records.FindingsThe near-field ground motion of the Maduo earthquake has an obvious directional effect, it is more likely to cause bridge seismic damage. Considering the longitudinal slope of the bridge and adopting the continuous girder bridge form, the beam end displacement of the curved bridge can be effectively reduced, and the collision force of the block and the bending moment of the pier bottom are reduced, so the curved bridge with longitudinal slope is adopted.Originality/valueCombined with the seismic damage phenomenon of bridges in real earthquakes, the seismic damage mechanism and vulnerability characteristics of high-pier curved girder bridges are discussed by the numerical simulation method, which provides technical support for the application of such bridges in high seismic intensity areas.

Seismic Response Analysis of a Curved Bridge under Near-Fault and Far-Field Ground Motions

To study the influence of near-fault and far-field (FF) ground motions on a curved girder bridge, a 1:10 scale curved bridge shaking table test model was constructed. Three types of ground motions, namely, near-fault pulse (NP), near-fault non-pulse (NN), and FF ground motions, were selected and employed in the test model. The test results indicated that the seismic response of the curved bridge in the excitation of NP ground motion is significantly higher than that in the excitation of NN and FF ground motions, and is destructive to the curved bridge. The displacement of the curved bridge has spatial characteristics in the excitation of NP ground motions. The rotation generated by the curved bridge is easy to cause bearing shedding or girder falling at the low pier. The amplification of pier height increases the displacement response at the high pier.

Comparative study of numerical simulation methods for seismic pounding of adjacent girder of curved girder bridges

Under seismic action, non-uniform collision will occur between the main beams of curved beam bridge, which may lead to local damage of front beam or rear beam. At present, the research on collision effect is mainly based on straight beam bridge, and there is still a lack of relevant research on seismic collision of curved beam bridge. Taking two adjacent typical curved bridges as examples, this paper establishes contact elements (linear elastic model, Kelvin model and Hertz model) and solid elements (three-dimensional contact friction model) which can fully reflect the physical characteristics of seismic collision of curved bridges. By comparing the numerical simulation methods of seismic collision, the advantages and disadvantages of the existing numerical simulation methods in the seismic response analysis of curved bridges are evaluated. The results show that the calculation results of Kelvin model and three-dimensional contact friction model have the least error and high calculation efficiency, and are suitable for the seismic analysis of curved beam bridges.

Dynamic Performance of Straddle Monorail Curved Girder Bridge

In this work, a monorail vehicle-bridge coupling (VBC) model capable of accurately considering curve alignment and superelevation is established based on curvilinear moving coordinate system, to study the VBC vibration of straddle monorail curved girder bridge and the relevant factors influencing VBC. While taking Chongqing Jiao Xin line as an example, the VBC program is compiled using Fortran, where the reliability of algorithm and program is verified by the results of Chongqing monorail test. Moreover, the effects of curve radius, vehicle speed, and track irregularity on the corresponding vehicle and bridge vibrations are compared and analyzed. It is observed that the test results of lateral vibration acceleration (LVA) and vertical vibration acceleration (VVA) of track beam, and LVA of vehicle, are consistent with the simulation results. Owing to the track irregularity, vibration of track beam and vehicle increases significantly. Besides, an increase in vehicle speed gradually increases the vibration of track beam and vehicle. For the curve radius (R) ≤ 200 m, lateral and vertical vibrations of the track beam and vehicle decrease significantly with an increasing curve radius. Alternatively, when 200 m

Shaking Table Test of High Pier and Small Radius Curved Bridge under Multi‐point Excitation

The non‐uniform stratum and uneven surface have the complicated seismic spatial variability. The seismic response of high pier and small radius curved bridge caused by the seismic specificity of this kind of terrain has not been systematically studied. According to the multi‐point excitation theory of long‐span structures and the similar theory of shaking table test in model structures, a high pier with small radius curved girder bridge was used as the research object. The shaking table test of real bridge model was carried out to study the seismic response laws of this kind of bridge under multi‐point excitation. The results show that the designed seismic wave expansion device can meet the test requirements. The frequency of the model structure decreases rapidly and the damping ratio increases during the whole test process. The local terrain effect amplifies the seismic response of high pier and small radius curved bridge. The seismic response of high pier and small radius curved bridge is affected by different frequency spectrum seismic waves, and there is a big difference. Based on the above results, the impact of multi‐point excitation should be considered in seismic design of high pier with small radius curved bridge.

Analysis on the Causes of Cracks in Curved Box Girder Bridges with Small Radius

At present, curved box girder bridges with small radius is widely used in modern highway and urban road interchange flyover, especially in the design of ramp bridge of interchange flyover. Taking the ramp of Liaoyang Road to Haier Road Flyover in Laoshan District of Qingdao as an example, this paper calculates and compares the first principal stress at different positions of typical cross-sections by elementary beam theory and numerical calculation theory, and analyzes the mechanical reasons for serious cracks in the bridge.

Finite Element Analysis Of Continuous Curved Girder Bridge

Reinforced concrete continuous curved girder bridge is an important structure in highway traffic, due to the complex stress condition of the structure, the numerical simulation analysis before bridge design is particularly important. The finite element method is used to establish the calculation model of reinforced concrete continuous curved girder bridge, according to the load distribution characteristics during the construction and operation of the bridge, the calculation and analysis conditions of the bridge are designed, the most unfavourable position of bridge load is analysed. The results show that, the maximum longitudinal stress of bridge usually occurs at the middle section or support of continuous beam span, this is mainly the stress distribution law of continuous beam structure, the vertical displacement of the bridge shows regular fluctuations at the support and each middle span. The research results provide a reference for the design and construction of reinforced concrete continuous curved girder bridge.

Finite element analysis of continuous curved girder bridge

Reinforced concrete continuous curved girder bridge is an important structure in highway traffic, due to the complex stress condition of the structure, the numerical simulation analysis before bridge design is particularly important. The finite element method is used to establish the calculation model of reinforced concrete continuous curved girder bridge, according to the load distribution characteristics during the construction and operation of the bridge, the calculation and analysis conditions of the bridge are designed, the most unfavourable position of bridge load is analysed. The results show that, the maximum longitudinal stress of bridge usually occurs at the middle section or support of continuous beam span, this is mainly the stress distribution law of continuous beam structure, the vertical displacement of the bridge shows regular fluctuations at the support and each middle span. The research results provide a reference for the design and construction of reinforced concrete continuous curved girder bridge.

Effect of Different Constraint Systems on the Seismic Response of Double-Deck Curved Girder Bridges

Double-deck curved girder bridges can achieve large climb in a short distance, and their seismic response differs from that of regular bridges due to their special structural form. The constraint system of bridges, which consists of bearings and shear keys, has a key influence on the seismic response of the bridge structure. Accordingly, this research aims to develop a reasonable constraint system for double-deck curved girder bridges. A finite element simulation of a double-layer curved steel box girder bridge is also conducted to compare some indexes, which are the displacement of bearings with the curvature of the pier section. The shear bolt is selected as the limit device to study the influence of shear bolts and different bearings on the seismic response of the double-deck curved girder bridge structure. Under the influence of ground motion, the displacement of the upper bearings of double-layer curved girder bridges is generally larger than that of the lower bearings. The double-layer constraint system makes the section curvature and ductility in the middle of the pier smaller than that at the top and bottom of the pier. The spherical steel bearings have a small displacement, whereas the pier has a large internal force. After setting the shear bolts, the displacement of the spherical steel bearings decreases, whereas the damage to bridge piers does not show obvious changes. When the displacement of elastomeric pad bearings increases, sliding occurs under a low ground motion intensity, thereby reducing the degree of damage to the bridge pier. Moreover, the application of shear bolts limits the displacement of bearings and subsequently increases the seismic force being transmitted to the pier whose damage is the most serious. However, the displacement of pot bearings is relatively small, and the displacements of the upper and lower layers are close. In addition, the seismic inertial force of the superstructure is relatively uniform, thereby protecting the piers to a certain extent. After setting the shear bolts, the deformation falls within an allowable range, whereas the damage to the bridge piers slightly increases. Therefore, combining pot bearings with shear bolts creates a reasonable constraint system for double-deck curved girder bridges.

Analysis of Friction-Slip Characteristics of Pot Bearings in Continuous Curved Girder Bridges

In order to study the influence of friction and slip effect of bearing on transverse deviation of concrete curved beam bridge, the solid model of basin rubber bearing was established by ANSYS. Based on this, the stress and deformation of PTFE plate, basin ring, compressed rubber block and base plate were analyzed in detail; the vertical of the bearing was simulated by finite element method. The load-displacement curves are compared with the bearing capacity test results of 2.5MN basin rubber bearing completed by the Highway Science Research Institute of the Ministry of Transportation. The results show that the basin rubber bearing has stable mechanical properties, and the maximum principal stress, vertical compression deformation and radial deformation of the bearing under the design vertical load satisfy the design requirements; the maximum error between the calculated value and the experimental value of the vertical compression deformation is 4.8%, which verifies the accuracy of the finite element model and is for the follow-up. Foundation for analysis of friction and slip characteristics of traveling bearings.

PARAMETER OPTIMIZATION OF LEAD RUBBER BEARINGS OF AN ISOLATED CURVED GIRDER BRIDGE

In order to improve the performance of an isolated curved girder bridge with lead rubber bearing (LRB), the mechanical parameters of LRB are analyzed and optimized. Firstly, the finite element model of a three-span isolated curved girder bridge is established by ANSYS. Nonlinear time history analyses are conducted with consideration of impact of yield force, elastic stiffness and post-yield stiffness. It is found that the key seismic responses of structure vary with mechanical parameters. The reasonable ranges of the parameters of isolated bearings are determined. Taking the sum of the pier base shear as the objective function, the mechanical parameters of LRB are optimized based on the zero-order optimization algorithm. Results show that yield force, elastic stiffness and post-yield stiffness have significant effect on seismic responses of the isolated curved girder bridge. When the bearings parameters are optimized, the peak displacement of the bearings is effectively controlled without increasing the base shear of the piers distinctly. The differences of shear between the side piers and the middle piers are reduced, and the shear distribution of each pier becomes uniform.

Experimental determination on the critical angle of seismic incidence of curved bridge

The shaking table model test mainly focuses on the study of seismic response law, aseismic performance and seismic damping and isolation effect of bridges with a single or multi-platform shaking table. Basically, the plane principal axis direction is adopted for the seismic input of structural models. Little research effort considering multi-angle seismic input has been reported in the structural model test. In this paper we designed and conducted a small-scale shaking table model test to study the seismic response law of the curved girder bridges with seismic input at different angles, and provided experimental verification for the theoretical method of the most unfavorable angle of seismic input. The experimental results show that the variation trend of component response to variation of the seismic input direction is consistent with that of the numerical analysis, which indicates that the designed device is effective.

Research on Shear Lag Effect of Three-span Continuous Curved Steel Box Girder Bridge

The normal stress of box-section beam under symmetrical load is the non-uniform characteristic called shear lag effect. Based on actual engineering project, the plate-beam finite element method is used to study the shear lag effect of the three-span continuous-curve steel box-girder bridge under the variety conditions of the curve radius, and the width span ratio, and the distribution of the shear lag effect in the longitudinal and horizontal direction under the symmetrical load are summarized in this paper, providing references for design of steel box-girder bridge. The results show that the shear lags of steel box girders are all positive shear lags under symmetrical loads. Under the conditions of three parameters, the curve radius and the width-span ratio have a great influence on the shear lag effect of steel box girders, and the high-span ratio change has no obvious effect on the shear lag effect, and the shear lag effect of bottom plate is far less severe than the top plate.

Anti-overturning stability coefficient of curved girder bridges considering seismic action

To overcome the limitation of terrain and ground objects, curved girder bridges normally adopt a single column pier, on which a single bearing or double bearings with small spacing are seated, making it weak in anti-overturning ability under eccentric load. Presently, the vehicle centrifugal force and seismic action are rarely considered when calculating the anti-overturning stability and tend to aggravate the deflection of curved girder bridges. In this paper, a calculation method is proposed to determine the anti-overturning stability coefficient under earthquake; the calculating equation of anti-overturning stability coefficient under static action is modified. The results show that the influence of centrifugal force cannot be neglected. Otherwise, the calculation of overturning stability is unsafe. The anti-overturning stability of curved girder bridges under earthquake is lower than that under static action. Further, the effect of different structural parameters on the anti-overturning stability coefficient under static and seismic action is similar: the anti-overturning stability coefficient decreases with the growth of bridge deck width, while first decreases sharply and then increases slowly with the growth of curvature radius.