Dynamic Response Of Bridge Structure Research Articles

Analysis of Bridge Dynamics and Response Characteristics Under The Influence of Axle Coupling Vibration

To ensure the safety and stability of high-speed rail lines and reduce external interference, it is essential to build a large number of elevated bridges. These elevated bridges account for a considerable proportion of the total length of high-speed rail lines. However, when high-speed rail lines pass through earthquake prone areas, the likelihood of earthquakes occurring when trains pass through bridges increases significantly. Therefore, it is necessary to study the dynamic response of bridge structures under earthquake action to ensure the safety of bridges during train operation and operation. The optimization scheme proposed in this article has undergone moderate impact tests, and the results show that the maximum lateral displacement of the bridge can reach 124 mm, while the maximum vertical acceleration is 5.16 m/s2, Exceeded the safety limit of 0.35 g. Through the analysis of train derailment coefficient, wheel load reduction rate, lateral sway force, lateral and vertical acceleration, and Spelling comfort index, we have come to the conclusion that bridges can ensure the safety of train operation in the absence of earthquakes and small earthquakes, and can also maintain certain stability under medium and large earthquakes. These research results have important guiding significance for the design and construction of high-speed rail lines. By optimizing the bridge structure and adopting relevant technical measures, the seismic disaster resistance of high-speed rail lines can be further improved, ensuring the safety and comfort of passengers during travel. At the same time, these research results also provide useful reference and inspiration for the construction and improvement of future high-speed rail lines.

Numerical investigation of transverse steel damper (TSD) seismic system for suspension bridges considering pounding between girder and towers

Transverse steel damper (TSD) is a promising passive control device used for seismic isolation and has been validated to feasibly balance the girder transverse seismic displacement and inertial force in cable-stayed bridges. However, for the TSD system, transverse pounding could occur at the locations of girder and tower legs when the gap size is insufficient to accommodate the girder-support transverse relative displacement under major earthquakes. Transverse pounding can significantly affect the dynamic responses of bridge structures, hence, the present paper investigates the effectiveness of TSD as a control strategy for transverse seismic responses in long-span bridge structures (i.e., suspension bridges), accounting also for the influence of the pounding effect in the dynamic response analysis. A typical suspension bridge is considered for case study purposes, and four transverse girder-support connection systems are investigated, including the conventional fixed and sliding-free connections and the TSD connections with and without pounding effect. A comprehensive comparison of the seismic performance among these transverse restraining systems is conducted through Incremental Dynamic Analysis and fragility analysis. Additionally, the effect of seismic-induced pounding in the TSD system is assessed from an energetic point of view. The results show that, for the suspension bridge with TSDs as the transverse control strategy, a satisfactory balance between force and displacement demands can be obtained in small-to medium-intensity earthquakes. However, the pounding between the girder and tower legs during large-intensity earthquakes can substantially increase the seismic demands in the tower legs.

Measurement of Quasi-Static and Dynamic Displacements of Footbridges Using the Composite Instrument of a Smartstation and an Accelerometer: Case Studies

Monitoring the dynamic responses of bridge structures has received considerable attention. It is important to synchronously measure both the quasi-static and dynamic displacements of bridge structures. However, the traditional accelerometer method cannot capture the quasi-static displacement component, although it can detect the dynamic displacement component. To this end, a novel composite instrument of a smartstation was proposed to monitor vibration displacements of footbridges. Full-scale experiments were conducted on a footbridge to validate the feasibility of the composite instrument-based monitoring method. A Chebyshev filter and wavelet algorithms were developed to process the composite instrument measurements. It was concluded that the measurement noise of the composite instrument was mainly distributed in a frequency range of 0–0.1 Hz. In two case studies with displacement peaks of 5.7–10.0 mm and 1.3– 2.5 mm, the composite instrument accurately identified the quasi-static and dynamic displacements. The composite instrument will be a potential tool for monitoring structural dynamics because of its enhanced overall performance.

Influence of Fluid Viscous Damper on the Dynamic Response of Suspension Bridge under Random Traffic Load

Fluid viscous dampers (FVDs) are widely used in long-span suspension bridges for earthquake resistance. To analyze efficiently the influences of FVDs on the dynamic response of a suspension bridge under high-intensity traffic flow, a bridge-vehicle coupling method optimized by isoparametric mapping and improved binary search in this work was first developed and validated. Afterwards, the traffic flow was simulated on the basis of monitored weigh-in-motion data. The dynamic responses of bridge were analyzed by the proposed method under different FVD parameters. Results showed that FVDs could positively affect bridge dynamic response under traffic flow. The maximum accumulative longitudinal girder displacement, longitudinal girder displacement, and longitudinal pylon acceleration decreased substantially, whereas the midspan girder bending moment, pylon bending moment, longitudinal pylon displacement, and suspender force were less affected. The control efficiency of maximum longitudinal girder displacement and accumulative girder displacement reached 33.67% and 57.71%, longitudinal pylon acceleration and girder bending moment reached 31.51% and 7.14%, and the pylon longitudinal displacement, pylon bending moment, and suspender force were less than 3%. The increased damping coefficient and decreased velocity exponent can reduce the bridge dynamic response. However, when the velocity exponent was 0.1, an excessive damping coefficient brought little improvement and may lead to high-intensity work under traffic flow, which will adversely affect component durability. The benefits of low velocity exponent also reduced when the damping coefficient was high enough, so if the velocity exponent has to be increased, the damping coefficient can be enlarged to fit with the velocity exponent. The installation of FVDs influences dynamic responses of bridge structures in daily operations and this issue warrants investigation. Thus, traffic load should be considered in FVD design because structural responses are perceptibly influenced by FVD parameters.

Dynamic Response of Railway Bridges under Heavy-Haul Freight Trains

In the freight railway bridge, the increase of the train running speed and train axle loads can enlarge dynamic response (DR) of the railway bridges, which leads to excessive vibration of bridges and endangers the structural safety. In this paper, a three-dimensional coupled finite element (FE) model of a heavy-haul freight train-track-bridge (HHFTTB) is established using multibody dynamics theory and FE method, and the DR for the coupled system of HHFTTB are solved by ABAQUS/Explicit dynamic analysis method. The field-measured data for a 32 m simply supported prestressed concrete beam of a heavy-haul railway in China are analyzed, and the validity of the FE model is verified. Finally, the effects of train formation number, train running speed, and train axle loads on DR of the heavy-haul railway bridge structures are studied. The results show that increasing the train formation number only has an influence on DR duration of the bridge structure, rather than the peak value of DR, when the train formation number exceeds a certain number; besides, the train axle loads and train running speed have significant influence on DR of the bridge structure. The results of this study can be used as reference for the design of heavy-haul railway bridges and the reinforcement transformation of existing railway bridges.

Experiment and Numerical Simulation of the Dynamic Response of Bridges under Vibratory Compaction of Bridge Deck Asphalt Pavement

Vibratory compaction of bridge deck pavement impacts the structural integrity of bridges to certain degrees. In this study, we analyzed the dynamic response of different types of concrete-beam bridges (continuous beam and simply supported beam) with different cross-sectional designs (T-beam and hollow-slab beam) under vibratory compaction of bridge deck asphalt pavement. The dynamic response patterns of the dynamic deformation and acceleration of bridges under pavement compaction were obtained by performing a series of field experiments and a three-dimensional finite element simulation. Based on the finite element model, the dynamic responses of bridge structures with different spans and cross-sectional designs under different working conditions of vibratory compaction were analyzed. The use of different vibration parameters for different bridge structures was proposed to safeguard their structural safety and reliability.

Influence of soil-structure interaction on the dynamic response of continuous and integral bridge subjected to moving loads

ABSTRACT In this paper, the effects of high-speed moving train loads over a non-prismatic continuous and integral bridge are investigated, in which the dynamic soil-structure interaction (SSI) analysis is comprehensively considered. Initially, a complete-pile model and an equivalent spring model of the continuous bridge are analyzed and compared. Two complex cases of track loading for the complete-pile model Case-I (C-I): one train moving on the single track, and Case-II (C-II): two trains moving on both the tracks entering at same instant but in opposite direction), under the CRH3 train loading, are studied. The variations in dynamic responses of the bridge for these cases confirm the influence of soil-structure interaction. C-II represents higher vertical displacement and acceleration bridge response compared to the C-I for both, continuous and integral bridge. It is proposed to analyze a detailed 3D model under critical loading condition for acquiring an accurate vertical dynamic response of bridge structure.

Vibration Suppression of Wind/Traffic/Bridge Coupled System Using Multiple Pounding Tuned Mass Dampers (MPTMD).

Dynamic responses of highway bridges induced by wind and stochastic traffic loads usually exceed anticipated values, and tuned mass dampers (TMDs) have been extensively applied to suppress dynamic responses of bridge structures. In this study, a new type of TMD system named pounding tuned mass damper (PTMD) was designed with a combination of a tuned mass and a viscoelastic layer covered delimiter for impact energy dissipation. Comprehensive numerical simulations of the wind/traffic/bridge coupled system with multiple PTMDs (MPTMDs) were performed. The coupled equations were established by combining the equations of motion of both the bridge and vehicles in traffic. For the purpose of comparing the suppressing effectiveness, the parameter study of the different numbers and locations, mass ratio, and pounding stiffness of MPTMDs were studied. The simulations showed that the number of MPTMDs and mass ratio are both significant in suppressing the wind/traffic/bridge coupled vibration; however, the pounding stiffness is not sensitive in suppressing the bridge vibration.

THEORETICAL ANALYSIS OF DYNAMIC RESPONSE OF A BRIDGE SECTION LOADING BY THE IMPULSIVE FORCE

<p>The work in seismic design of bridges is needed to develop physical models and mathematical theory, based on which will be assessed and quantified the dynamic response of bridge structures subjected to stress arising from road traffic or seismic activity.</p><p>The need for this modeling is imposed three requirements: to ensure the structural integrity of the bridge elements for subjected impulsive, proper choice of dynamic insulation elements placed as a interface between the superstructure and infrastructure, as well as analysis of effects on joints in these situations demand. This paper proposes a physical model of a general nature, enabling customization depending on the specific constructive bridge, or the way it is solicited. Customize this model was developed for this study based on the existing viaduct Transylvania highway located between km 29 +602.75 and km 29 +801.25.</p>

Estimation of nonlinearities from pseudodynamic and dynamic responses of bridge structures using the Delay Vector Variance method

Analysis of the variability in the responses of large structural systems and quantification of their linearity or nonlinearity as a potential non-invasive means of structural system assessment from output-only condition remains a challenging problem. In this study, the Delay Vector Variance (DVV) method is used for full scale testing of both pseudo-dynamic and dynamic responses of two bridges, in order to study the degree of nonlinearity of their measured response signals. The DVV detects the presence of determinism and nonlinearity in a time series and is based upon the examination of local predictability of a signal. The pseudo-dynamic data is obtained from a concrete bridge during repair while the dynamic data is obtained from a steel railway bridge traversed by a train. We show that DVV is promising as a marker in establishing the degree to which a change in the signal nonlinearity reflects the change in the real behaviour of a structure. It is also useful in establishing the sensitivity of instruments or sensors deployed to monitor such changes.

Parametric Simulation of Nonlinear Shear Key Behavior on the Seismic Response on Bridge Abutments

The effects of a phenomenological non-linear model for transverse bridge abutment shear keys on the dynamic response of a typical reinforced concrete bridge are investigated. The dynamic response of bridge structures modeled with a fully linear model, based on the current California Department of Transportation (Caltrans) Seismic Design Criteria (SDC), are compared to analysis results which incorporate a non-linear ductile model for the transverse abutment shear key. Various bridge geometries are considered to determine which common design parameters affect the accuracy of the current linear models used in design. In each case, the linear and non-linear models are subject to a suite of 80 ground acceleration time histories and the maximum lateral bent deformations are compared. The results suggest that the linear model currently used in analysis and design of California bridges is, in general, conservative across a wide range of configurations and fundamental periods of vibration (0.5s – 1.4s). Column dis...

Finite Element Analysis on Dynamic Response of Bridge Structures under Moving Loads with Uniform Speed

The dynamic response of simple supported beam under the moving load is analyzed. The finite element analysis software MIDAS is used to simulate the process of when the uniform constant force moving through the simply supported beam. The first 5 natural frequencies of simply supported beam are obtained with the modal analysis and compared with the analytical solution. The feasibility of the finite element method is verified.

Dynamic Demand of Bridge Structure Subjected to Vessel Impact Using Simplified Interaction Model

Assessing the dynamic demand using general-purpose finite-element codes is not only low in efficiency, but also unaccepted in practical application due to the complicated nonlinear dynamical behaviors of vessel-bridge collision. In this paper, an alternative simplified interaction model is presented to evaluate the dynamic demand of bridge structure under vessel impact efficiently. In this method, ship motion is regarded as the motion of single degree of freedom, and ship-bow is modeled by a nonlinear spring element (only compression) connected to bridge structure. A quasi-static method is employed to obtain the nonlinear static relationships between impact forces and crush depths of ship-bow, and the effect of the height of pile cap is discussed. Based on two different approaches, the influence of strain-rate effect on impact force is taken into account to obtain the corresponding dynamic crush curves, which are developed for the proposed interaction model. Results show that the dynamic responses of bridge structures using the simplified interaction models are in good agreement with the general-purpose collision analyses, while the former computation efficiency is improved obviously.

Vibration of railway bridges under a moving train by using bridge-track-vehicle element

During the last two decades, much attention has been paid to various vibration problems associated with railways. They include the dynamic response of railway bridges and railway tracks at grade under the action of moving trains. However, studies on the role of track structures on the vibration of railway bridges are rather limited. In this paper, a new element called bridge-track-vehicle element is proposed for investigating the interactions among a moving train, and its supporting railway track structure and bridge structure. The moving train is modelled as a series of two-degree-of-freedom mass-spring-damper systems at the axle locations. A bridge-track-vehicle element consists of vehicles modelled as mass-spring-damper systems, an upper beam element to model the rails and a lower beam element to model the bridge deck. The two beam elements are interconnected by a series of springs and dampers to model the rail bed. The investigation shows that the effect of track structure on the dynamic response of bridge structure is insignificant. However, the effect of the bridge structure on the dynamic response of the track structure is considerable.

LARSA 2000: Seismic Analysis of Bridges with Seismic Isolation and Energy Dissipation Devices

During the past decade the need to perform nonlinear static and dynamic analyses on bridge structures has increased significantly. Nonlinear dynamic analysis has become the approach that is used when protective systems such as base isolators and isolation systems are present in the bridge structure. The commercial computer programs available that are used for these types of analyses and that can be understood and used by structural bridge engineers have been far from adequate. Recently, the research community has produced a number of useful computer programs. Among these are the IDARC-Bridge and 3D-BASIS family of programs from the State University of New York at Buffalo. Bridge engineers are not usually familiar with the available computer codes primarily used by researchers, and it is generally known that these programs are not user friendly. Prediction of the nonlinear dynamic responses of bridge structures has presented other challenges. These range from the volume of input and output to the computational effort needed to obtain solutions. The increase in computer speed and the use of faster-solution algorithms have drastically reduced the time needed to perform iterative nonlinear dynamic analysis. Use of the Microsoft Windows-based standardized graphical user interface with the ability for the seamless exchange of data between programs makes the volume of input and output manageable. The implementation of 3D-BASIS-ME—type nonlinear base isolators and isolation systems and the analysis methods used in the family of Microsoft Windows-based software LARSA, with which bridge engineers have become familiar over the years using a wide range of applications for bridges and buildings, are presented.

The influence of roadway surface irregularities and vehicle deceleration on bridge dynamics using the method of lines

Abstract In this paper, an analysis of vehicle-bridge interaction problems, taking into account the dynamic effects induced by vehicle bouncing due to roadway surface irregularities and varying vehicle speeds, is presented. The problem formulation and solution methodology include the effects of vehicle suspension systems, the vehicle travelling path, and the arbitrary boundary conditions and geometry of the bridge superstructure. The kinematic coupling reflecting the dynamic interaction between the traversing vehicle and the vibrating bridge superstructure is explicitly treated in the problem. Vehicle models used in this study take into account the stiffness and damping characteristics of vehicle suspension and tires, and permit the inclusion of a variety of truck configurations. The spatial discretization of the governing differential equation of the vehicle-bridge system is based on the finite element method. The resulting matrix ordinary differential equation is then discretized with respect to time on the basis of the Newmark method. The process of reduction of a partial differential equation into a matrix ordinary differential equation through a spatial discretization procedure, and then solving this expression using a time integration technique, is referred to as the numerical method of lines. Since the consideration of the vehicle-bridge interaction introduces non-linearity into the problem formulation, a multipredictor-corrector scheme is adopted in the solution procedure to obtain accurate results. Numerical examples, illustrating the influence of roadway surface irregularities and vehicle deceleration on the dynamic response of bridge structures, are provided to illustrate the validity and efficiency of the proposed formulation and solution methodology.