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The indirect method for bridge modal identification based on the response of moving vehicles has attracted widespread attention in recent years. However, most existing studies only focus on the simply supported bridge, while continuous girder bridges are widely used in practical engineering. Therefore, this study proposes an indirect frequency identification method for continuous girder bridges. First, the mode shape formula of the equal-span continuous beam is deduced using the three-moment equations, and the analytical solution of the vehicle vibration response is deduced via the vehicle–bridge coupled vibration theory. Second, the derived analytical solution is verified through numerical analysis results and field test results. Finally, the effects of bridge and vehicle parameters on the frequency identification accuracy are analyzed. The results show that a reasonable frequency of the trailer should be selected to avoid the resonance between the vehicle and the bridge for better performance. The research findings can provide a reference for the indirect identification of continuous girder bridges based on the response of moving vehicles. [ABSTRACT FROM AUTHOR]

Wind loads have become one of the key influencing factors for the running safety of vehicles and comfort of passengers. The investigation of the wind speed spectrum characteristics of a moving vehicle under turbulent crosswinds is of great importance. Expressions of the wind speed spectrum of a moving vehicle were obtained from the von Kármán spectrum, based on Taylor's frozen flow hypothesis. The influencing factors, including the ratio of the vehicle speed to the wind speed and wind yaw angles, were analyzed. The change rules of the wind speed spectrum peak and its corresponding frequency were also studied. The results show that the wind speed spectrum peak values of the moving vehicle were larger than those of the static vehicle. The wind speed spectrum peak values corresponding to the moving vehicle were first increased and then decreased, as the wind yaw angles increased. Some of the frequencies corresponding to the longitudinal wind speed spectrum values of the moving vehicle were smaller than those of the static vehicle. Therefore, the energy had been transferred to the lower frequency. For the moving vehicle, the frequency values corresponding to the longitudinal wind speed spectrum peak were first increased and then decreased, as the ratio of the vehicle speed to the wind speed and the wind yaw angle increased. [ABSTRACT FROM AUTHOR]

This study presents a correction approach that can capture the discontinuities in the bending moment and shear force in the dynamic analysis of beam-like structures traveled by a moving vehicle. The proposed approach was based on the Dynamic Modal Acceleration Method (DyMAM) to correct the dynamic response of the supporting structure with a reduced number of vibration modes. The use of a two-axle vehicle model was adopted to consider the pitching effect in the presence of surface irregularity and damping. The interacting forces between the beam and vehicle were filtered to avoid undesirable highfrequency contributions. Subsequently, a new formulation for the entire vehicle-beam system was obtained. The corresponding equation was solved using the Newmark numerical scheme to obtain the system responses in each time step. A numerical example was illustrated, showing that the proposed method was in close agreement with previous correction solutions in the vehicle-beam interaction analysis. [ABSTRACT FROM AUTHOR]

This article proposes a method for optimizing multiple tuned mass damper (TMD) devices for reducing bridge vibration as a vehicle passes over it. The method can design multiple TMD parameters simultaneously for different modes contributing to multiple resonance peaks. Moreover, the study analyzed the vibration of bridges with uncertain parameters. This study's motivation is based on the optimal design of TMDs for bridge structures under external forces, such as the loads of moving cars and high-speed trains. In this case, the resonant response phenomenon can only happen at specific frequencies. The proposed optimization was developed based on the H2 norm method to design the TMD parameters. The target of the present method is to minimize the response peaks around the resonance frequencies. Moreover, the contribution of the excited modes to each other at their resonance frequencies is considered. The TMD parameters were found to demonstrate good performance for reducing the vibration of bridges due to moving vehicles. [ABSTRACT FROM AUTHOR]

The traditional direct measurement method of dynamic displacement in bridge load test has the problems of complicated equipment installation, difficult operation and high cost. Based on the existing research results, an indirect measurement method of dynamic displacement of bridges was proposed using the dynamic-static separation of measured acceleration and multiple baseline correction strategies. After the baseline of measured acceleration data was corrected to eliminate overall deviation, the filter with FFT was used to remove high frequency noise. The dynamic-static separation was applied to achieve quasi-static and free vibration response before integration and final superposition. A new multiple baseline correction method was proposed considering the difference of dynamic and static response characteristics to achieve the effective elimination of trend term errors. The framework and process of the proposed method was established and then verified based on a real bridge in-situ dynamic load test. The dynamic displacements of bridge under vehicle with 20~40 km/ h speeds were estimated based on the proposed method by measured accelerations. The curves of estimated and directly measured displacements were compared. The results show that good agreement and the relative peak errors are in the range of 1.68%~5.29%. It is concluded that the proposed method has a satisfied accuracy and can be applied in engineering practice. [ABSTRACT FROM AUTHOR]

Wind load is one of the controlling loads for moving vehicles. Existing studies on the wind-induced response of vehicles mostly apply traditional wind spectra directly to the vehicles, overlooking their motion status. Fluctuating wind characteristics encountered by linearly moving vehicles were investigated in this paper. The traditional static frame of view was adjusted to a moving one, two principal flow directions were considered and the idea of positional equivalence introduced in Taylor frozen assumption was extended to the moving direction. A fluctuating wind power spectral density (PSD) was proposed. Then a novel test was designed to enable a measuring probe to travel across a wind field. The fluctuating wind characteristics encountered by moving points are quite different from those encountered by a static point. The integral scale decreases as the speed ratio of the measuring point to the wind increases, and an elliptic model was suggested. The proposed PSD aligns well with the test results, indicating that it can be used to accurately characterize the fluctuating wind load encountered by moving vehicles. Both the test results and the numerical analysis showed that as the speed ratio increases, the PSD and energy spectrum as a whole migrate to higher frequencies. • Actual fluctuating wind load encountered by a linearly moving vehicle was explored. • Fluctuating wind characteristics encountered by a moving vehicle was theoretically and experimentally studied. • A fluctuating wind spectral model was proposed for moving vehicles. • An empirical elliptic model was suggested for turbulence integral scale. [ABSTRACT FROM AUTHOR]

Automatic pedestrian detection in a vehicle is of vital importance in Advanced Driver Assistance Systems (ADAS). Sensors currently used are based on cameras, radars and lidars, whose performance is degraded in environments with reduced visibility: night, smoke, fog, etc. This paper has validated the use of an active array of 150 MEMS (Micro-Electro Mechanical Systems) microphones incorporated into a conventional car moving in real urban traffic conditions, with the system working in real time, at a rate of 8 detections per second. Together with beamforming, Constant False Alarm Rate (CFAR) detection and lane detection algorithms, a crucial algorithm has been incorporated for the proper performance of the system that discriminates the detections of objects or pedestrians generated by the system from the false alarms generated by road imperfections, such as bumps, cracks, etc. Based on 6000 captures, performed with the car moving at 30 km/h, which is the typical speed limit in urban environments, it has been possible to detect pedestrians positioned at a distance from the car varying between 5 and 20 m, with a detection probability of 0.91 and a false alarm probability of 0.01. The results obtained have validated the effectiveness of using active acoustic arrays in the field of pedestrian detection and position estimation from moving cars in urban environments. The fusion of the presented system with the systems currently used for this purpose, would significantly improve the performance of pedestrian detection systems interacting with AEB (Automatic Emergency Breaking) systems, extending their operability to environments with reduced visibility, and resulting in the reduction in the number of possible collisions with pedestrians, thus increasing their safety. [Display omitted] • Automotive and transportation industries try to reduce traffic accidents involving pedestrians. • Acoustic system based on a low-cost MEMS microphone array. • This system can be used to detect and estimate the position of a person. • This system performs properly mounted on a vehicle moving in urban environments. • This system improves the performance of pedestrian detection in reduced visibility environments. [ABSTRACT FROM AUTHOR]

Wind loads have become one of the key influencing factors for the running safety of vehicles and comfort of passengers. The investigation of the wind speed spectrum characteristics of a moving vehicle under turbulent crosswinds is of great importance. Expressions of the wind speed spectrum of a moving vehicle were obtained from the von Kármán spectrum, based on Taylor’s frozen flow hypothesis. The influencing factors, including the ratio of the vehicle speed to the wind speed and wind yaw angles, were analyzed. The change rules of the wind speed spectrum peak and its corresponding frequency were also studied. The results show that the wind speed spectrum peak values of the moving vehicle were larger than those of the static vehicle. The wind speed spectrum peak values corresponding to the moving vehicle were first increased and then decreased, as the wind yaw angles increased. Some of the frequencies corresponding to the longitudinal wind speed spectrum values of the moving vehicle were smaller than those of the static vehicle. Therefore, the energy had been transferred to the lower frequency. For the moving vehicle, the frequency values corresponding to the longitudinal wind speed spectrum peak were first increased and then decreased, as the ratio of the vehicle speed to the wind speed and the wind yaw angle increased.

This paper provides a finite element analysis of laminated composite plates under the action of a moving vehicle. The vehicle is modeled as a rigid body with four suspension systems, each consisting of a spring-dashpot. Overall, the vehicle possesses three degrees of freedom: vertical, rolling, and pitching motions. The equations of motion of the plate are deduced based on first-order shear deformation theory. Using the Euler-Lagrange equations, the system of coupled equations of motion is extracted and solved by using the Newmark time discretization scheme. The algorithm is validated through the comparison of both the free and forced vibration results provided by the present model and exact or numerical results reported in the literature. The effects are investigated of several system parameters on the dynamic response.

The dynamic analysis is carried out of a laminated composite plate coupled with a piezoelectric energy harvester under the action of a moving vehicle. The finite element method along with Newmark's method are applied to solve the discretized equations. Results are presented for two main cases: (i) free and forced vibrations of the laminated composite plate with no harvester and (ii) forced vibrations of the plate coupled with the energy harvester. Several parameters – such as the symmetric and anti-symmetric layups, length of the harvester, and piezoelectric material parameters – are considered to study their effects on the electrical output. [ABSTRACT FROM AUTHOR]

The recognition of the characters in the license plate has been widely studied, but research to recognize the character of the license plate on a moving car is still rarely studied. License plate recognition on a moving car has several difficulties, for example capturing still images on moving images with non-blurred results. In addition, there are also several problems such as environmental disturbances (low lighting levels and heavy rain). In this study, a novel framework for recognizing license plate numbers is proposed that can overcome these problems. The proposed method in this study: detects moving vehicles, judges the existence of moving vehicles, captures moving vehicle images, deblurring images, locates license plates, extracts vertical edges, removes unnecessary edge lines, segments license plate locations, Indonesian license plate cutting character segmenting, character recognition. Experiments were carried out under several conditions: suitable conditions, poor lighting conditions (dawn, evening, and night), and unfavourable weather conditions (heavy rain, moderate rain, and light rain). In the experiment to test the success of the license plate number recognition, it was seen that the proposed method succeeded in recognizing 98.1 % of the total images tested. In unfavorable conditions such as poor lighting or when there are many disturbances such as rain, there is a decrease in the success rate of license plate recognition. Still, the proposed method's experimental results were higher than the method without deblurring by 1.7 %. There is still unsuccessful in recognizing license plates from the whole experiment due to a lot of noise. The noise can occur due to unfavourable environmental conditions such as heavy rain. [ABSTRACT FROM AUTHOR]

Micro-Doppler effects of moving vehicles in a radar system are mainly induced by the rotation of wheels, whose features are closely related to the numbers, positions and radiuses of wheels. These parameters of wheels are critical for the vehicle classification and recognition. However, most micro-Doppler features extraction works of vehicles are unable to explicitly extract parameters of wheels. In this paper, a parameter extraction method of vehicle wheels using micro-Doppler features based on the matching pursuit (MP) is proposed. The micro-Doppler signals of wheels are generally weak comparing to redundant echo signals induced by other irrelevant parts of the vehicle, which makes the micro-Doppler features difficult to extract. In this case, several signal atom sets are created according to the motion states of irrelevant parts of vehicle and MP is performed to suppress the redundant signals. After the suppression, micro-Doppler signals induced by wheels have become the major part of the echo signal. Another atom set is generated according to the rotational motion of wheels to perform MP again. Then the wheel parameters, such as the estimated numbers, positions and radiuses, are extracted. Simulation results demonstrate that the proposed method is feasible in feature extraction of moving vehicle. Besides, the accuracy can be guaranteed when the signal-to-noise ratio is greater than –5 dB.

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Bu çalışmada, tek açıklıklı köprülerin hareketli asılı kütle etkisindeki dinamik davranışı incelenmiştir. Ele alınan probleme ait hareket denklemi değişken katsayılı kısmi türevli diferansiyel denklem şeklinde elde edilmiş ve Newmark yöntemi ile sayısal olarak çözülmüştür. Dinamik analizlerde hız parametresi, kütle oranı, frekans oranı ve köprünün sönüm oranının köprünün ve taşıtın dinamik davranışı üzerindeki etkileri araştırılmıştır. Analizlerden elde edilen sonuçlar şekiller ve tablolar halinde sunulmuştur. Sonuçlar, dikkate alınan parametrelerin köprünün dinamik davranışı üzerinde önemli bir etkiye sahip olduğunu göstermiştir.

This article proposes a practical end-to-end neural network framework to detect tiny moving vehicles in satellite videos with low imaging quality. Some instability factors, such as illumination changes, motion blurs, and low contrast to the cluttered background, make it difficult to distinguish true objects from noise and other point-shaped distractors. Moving vehicle detection in satellite videos can be carried out based on background subtraction or frame differencing. However, these methods are prone to produce lots of false alarms and miss many positive targets. Appearance-based detection can be an alternative but is not well-suited since classifier models are of weak discriminative power for the vehicles in top view at such low resolution. This article addresses these issues by integrating motion information from adjacent frames to facilitate the extraction of semantic features and incorporating the transformer to refine the features for key points estimation and scale prediction. Our proposed model can well identify the actual moving targets and suppress interference from stationary targets or background. The experiments and evaluations using satellite videos show that the proposed approach can accurately locate the targets under weak feature attributes and improve the detection performance in complex scenarios. [ABSTRACT FROM AUTHOR]

Hinge joint damage is the main defect affecting the safety of assembled hollow slab bridges. The timely discovery of hinge joint damage is significant for guaranteeing the structural safety of assembled hollow slab bridges. This paper presents a damage detection approach for hinge joints of hollow slab bridges using mode shapes extracted from moving vehicle responses. A stationary excitation vehicle equipped with a shaker excites a bridge, another vehicle moves along the driving path, and its acceleration is collected to extract the mode shape, which is called the stationary excitation extraction mode (SEEM) method. First, the theoretical analysis model of the proposed method is established to analyze the response of the vehicle–bridge system, and the mode shape is extracted from vehicle acceleration by the Hilbert transform. An algorithm that requires no baseline is adopted to detect damage from the extracted mode shape. Then a procedure for damage detection in field testing is proposed in which the determination of important parameters is explained, including excitation frequency, moving vehicle departure time, and narrowband filtering. Finally, factors that affect the accuracy of the approach are studied by numerical analysis, including road roughness, vehicle speed, damage degree, and damage location. The results demonstrate that the damage detection approach for hinge joints is feasible at low vehicle speeds. [ABSTRACT FROM AUTHOR]

This paper provides a finite element analysis of laminated composite plates under the action of a moving vehicle. The vehicle is modeled as a rigid body with four suspension systems, each consisting of a spring- dashpot. Overall, the vehicle possesses three degrees of freedom: vertical, rolling, and pitching motions. The equations of motion of the plate are deduced based on first-order shear deformation theory. Using the Euler- Lagrange equations, the system of coupled equations of motion is extracted and solved by using the Newmark time discretization scheme. The algorithm is validated through the comparison of both the free and forced vibration results provided by the present model and exact or numerical results reported in the literature. The effects are investigated of several system parameters on the dynamic response. [ABSTRACT FROM AUTHOR]

Micro-Doppler effects of moving vehicles in a radar system are mainly induced by the rotation of wheels, whose features are closely related to the numbers, positions and radiuses of wheels. These parameters of wheels are critical for the vehicle classification and recognition. However, most micro-Doppler features extraction works of vehicles are unable to explicitly extract parameters of wheels. In this paper, a parameter extraction method of vehicle wheels using micro-Doppler features based on the matching pursuit (MP) is proposed. The micro-Doppler signals of wheels are generally weak comparing to redundant echo signals induced by other irrelevant parts of the vehicle, which makes the micro-Doppler features difficult to extract. In this case, several signal atom sets are created according to the motion states of irrelevant parts of vehicle and MP is performed to suppress the redundant signals. After the suppression, micro-Doppler signals induced by wheels have become the major part of the echo signal. Another atom set is generated according to the rotational motion of wheels to perform MP again. Then the wheel parameters, such as the estimated numbers, positions and radiuses, are extracted. Simulation results demonstrate that the proposed method is feasible in feature extraction of moving vehicle. Besides, the accuracy can be guaranteed when the signal-to-noise ratio is greater than -5 dB. [ABSTRACT FROM AUTHOR]

This paper provides a finite element analysis of laminated composite plates under the action of a moving vehicle. The vehicle is modeled as a rigid body with four suspension systems, each consisting of a spring-dashpot. Overall, the vehicle possesses three degrees of freedom: vertical, rolling, and pitching motions. The equations of motion of the plate are deduced based on first-order shear deformation theory. Using the Euler-Lagrange equations, the system of coupled equations of motion is extracted and solved by using the Newmark time discretization scheme. The algorithm is validated through the comparison of both the free and forced vibration results provided by the present model and exact or numerical results reported in the literature. The effects are investigated of several system parameters on the dynamic response.

The critical signal component extracted from the bridge response caused by a moving vehicle is normally used to construct damage index for damage detection. The dynamic response of bridges subjected to moving vehicle includes several components, among which the quasi-static component reflects the inherent characteristics of the bridge. In view of this, this paper presents a bridge damage detection method based on quasi-static component of the moving vehicle-induced dynamic response. First, damage-induced changes of the natural-frequency component, moving-frequency component and quasi-static component responses are investigated via a simply-supported beam bridge. The quasi-static component response is proved to be less sensitive to the moving velocity of the load and more suitable for damage detection. Subsequently, a quasi-static component response extraction method is proposed based on analytical mode decomposition (AMD) and moving average filter (MAF). The extracted quasi-static component response is further employed to localize and quantify damages. Finally, numerical simulations are conducted to examine the feasibility, accuracy and advantages of the proposed damage detection method. The results indicated that the proposed method performs well in different damage scenarios and is insensitive to the moving velocity of the load and road roughness. [ABSTRACT FROM AUTHOR]

Summary: Advances in smart infrastructure produces a natural demand of system identification techniques for structural health and performance monitoring that can be scaled to regions and large asset inventories. Conventional approaches require sensors to be installed, often in long‐term deployments, on the monitored infrastructure systems, which is a costly undertaking when thousands of systems (e.g., bridges) need to be monitored. This paper presents a novel mode shape identification method for bridges that uses data collected from moving vehicles as input—a paradigm that can overcome limitations associated with conventional approaches. The method consists of two steps. First, the data collected from moving measurement points are mapped to virtual fixed points to generate a sparse matrix. Then, a "soft‐imputing" technique is employed to fill the sparse matrix. Finally, a singular value decomposition is applied to extract the mode shapes of the bridge. Experiments with synthetic, yet realistic, data are conducted to verify the method. The sensitivity of the proposed approach to different factors, including the number of vehicles, car speed, road roughness, and measurement errors, are also investigated. The results show that the proposed method is capable of identifying the mode shapes of the bridge accurately. [ABSTRACT FROM AUTHOR]

Longitudinal cracks at the bottom of the deck are a common form of hidden damage in box girder bridges. Timely detection of deck cracking is critical to ensure the safe operation of box girder bridges. This paper proposes a damage detection method for the deck of box girder bridges using mode shapes constructed from a moving vehicle. One stationary excitation vehicle excites the local bending modes of the deck, and the other vehicle moves along the planned path. The moving vehicle acceleration is collected to construct mode shapes on the driving path. First, generalized beam theory is used to analyze the dynamic behavior of the box girder bridge. The theoretical model of the proposed approach is built to analyze the response of the vehicle-bridge system under shaker excitation, and mapping relationship between the instantaneous amplitude of the vehicle response and the local bending mode of the deck is deduced. The damage indicator based on the mode curvature is used to determine the crack position. Then, a damage detection process for field testing is proposed. Technical details such as excitation parameters, driving path, and narrowband filtering are explained. Finally, factors that affect damage detection, including road roughness, crack length, and crack height are investigated via numerical analysis. Results show that the proposed method can detect medium damage. • Dynamic characteristics of the box girder bridge are analyzed through generalized beam theory (GBT). • Vibration characteristics of the deck are clarified based on the proportion of each GBT deformation mode. • Relation between the vehicle response and the bending mode of the deck is revealed by Hilbert transform. • Damage detection process for field testing of bridges is proposed, and technical details are explained. • Influence of road roughness, crack length and crack height, are investigated via numerical analysis. [ABSTRACT FROM AUTHOR]

Taking the scene of car fire and bus driving through fire source in highway tunnel as an example， a fire calculation model was established based on a tunnel project， and the dynamic influence law of vehicle motion speed on temperature distribution of tunnel fire was studied by using overset mesh technology and fire numerical simulation method. The results show that when the vehicle passes through the fire source at the speed of 11.11m/s， the smoke temperature at the top of the cross and longitudinal sections of the fire source is the lowest. When the influence of vehicle-induced airflow on the temperature distribution reaches the maximum， the cross sectional smoke temperature from the ignition lane to the vehicle passing through the lane shows a pattern of first decrease and then increase.In the range of 15m upstream of the highest temperature point， the longitudinal smoke temperature decays steadily， and the decay rate reaches maximum when the vehicle speed is 11.11m/s. [ABSTRACT FROM AUTHOR]

An effective procedure is proposed for extracting bridge frequencies including the higher modes using the vehicle collected data. This is enabled by the use of the contact-point response, rather than the vehicle response, for processing by the extreme-point symmetric mode decomposition (ESMD). The intrinsic mode functions (IMFs) so decomposed are then processed by the FFT to yield the bridge frequencies. A systematic study is conducted to compare the proposed procedure with existing ones, while assessing the effects of various parameters involved. The proposed procedure was verified in the field for a two-span bridge located at the Chongqing University campus. It was confirmed to perform better than the existing ones in extracting bridge frequencies inclusive of the higher modes. The following are the reasons: (1) the ESMD is more efficient than the EMD in that remarkably less IMFs are generated; (2) the modal aliasing problem is largely alleviated, which helps enhancing the visibility of bridge frequencies in general; and (3) the contact-point response adopted is free of the vehicle frequency, which makes the higher frequencies more outstanding and detectable. [ABSTRACT FROM AUTHOR]

In this study, a new test method for measuring the aerodynamic coefficients of structures by transiting test is presented with reference to the characteristics of vehicle movement, which can produce relative wind field. The basic theory of transiting test was constructed based on theoretical derivation and field test. First, the test devices of transiting test method were designed and assembled, and the test model was vertically and horizontally placed in the devices, respectively. Then, the processing method of test data was studied. Finally, after studying the influence of vehicle driving vibration, the test method was used to measure the lift and drag coefficients of an isosceles prism model which can be found in the references quoted, and Reynolds number effect is studied. A comparison with the results of wind tunnel tests obtained by Alonso G et al. is also presented and discussed. The transiting test provides a new testing method for the study of structural wind resistance. [ABSTRACT FROM AUTHOR]

Mode shapes estimated from the vehicle responses are normally used to detect bridge damage efficiently for their high spatial resolution. However, an updated baseline finite element model (FEM) is normally required to quantify damages for such an approach. A two-stage damage detection procedure is presented for bridges by utilizing the mode shape estimated from a moving vehicle. Damage locations are first determined through a damage localization index (DLI) defined by regional mode shape curvature (RMSC). Then the relationship between the damage extents and the RMSC changes is investigated by FEM simulation. Finally, an equation set to quantify the single and multiple damages is deduced by combining the RMSCs and the relationship between the damage extents and the RMSC changes established by an un-updated FEM. Numerical and experimental examples are carried out to verify the validity and efficiency of the two-stage method. The results revealed that it can localize and quantify damages with satisfactory precision by using the response measured from one sensor only. [ABSTRACT FROM AUTHOR]

A numerical simulation of a moving vehicle on the rigid roadway pavement with discontinuities is presented in this paper by using the data from one of the toll road segments in Indonesia. The analysis procedure considers the dynamic interaction between the vehicle and the rigid pavement. The rigid roadway pavement is modeled using the Kirchhoff theory of thin slab on elastic foundations. The aim of the numerical analysis is to obtain the vertical deflection in the middle of the slab, to obtain the time history of the slab deflection; and to identify the parameters of the sub-grade that has a significant effect on the dynamic response of the rigid roadway pavement. The equations of motion are derived in the form of partial differential equations of the fourth order. The mode shapes of the slab deflection are determined from the method of first and the second auxiliary equations of Levy-type in the x- and y-directions, which is also known as the Modified Bolotin Method (MBM). The equations of motion are solved numerically by using Mathematica. The influence of various parameters including the peak vertical velocity due to the moving vehicle, the stiffness of subgrade, the slab thickness and the road profile to the dynamic behavior of the rigid roadway pavement are studied in detail. The results obtained from the plate computing model in this paper are then compared and analyzed with the results computed using the finite element method by Strand 7 to show that the solution obtained using the MBM method is accurate. In addition, the paper aims to show that the thickness of the plate plays a significant role in the distribution of the bending stresses in plate discontinuities and is necessary for engineers to design rigid roadway pavements. [ABSTRACT FROM AUTHOR]

A real-time prediction method using a multilayer feedforward neural network is proposed for estimating vertical dynamic displacements of a bridge from the longitudinal strains of the bridge when vehicles pass across it. A numerical model for an existing five-girder bridge spanning 36 m proved by actual experimental values was used to verify the proposed method. To obtain a realistic vehicle distribution for the bridge, vehicle type and actual headways of moving vehicles were taken, and the measured vehicle distribution was generalized using Pearson Type III theory. Twenty-five load scenarios were created with assumed vehicle speeds of 40 km/h, 60 km/h, and 80 km/h. The results indicate that the model can reasonably predict the overall displacements of the bridge (which is difficult to measure) from the strain (which is relatively easy to measure) in the field in real time. [ABSTRACT FROM AUTHOR]

In this study, new general analytical models for correlation and power spectral density (PSD) functions of wind turbulence relative to a moving vehicle considering different wind direction angles under crosswinds without the use of Taylor's frozen turbulence hypothesis or the isotropic turbulence assumption were proposed. The auto-PSD calculation models relative to a moving vehicle with two different coherence functions relative to the ground were deduced, and a direct generating scheme, which can more efficiently generate the time histories of fluctuating wind speeds relative to a moving vehicle was developed. The accuracy of the proposed auto-PSD models was validated based on the models and direct generating scheme mentioned above. Furthermore, the coherence function model of wind turbulence relative to a moving vehicle was also proposed, and the accuracy of both the proposed coherence function model and the previous model were compared. The results show that without the use of Taylor's frozen turbulence hypothesis or the isotropic turbulence assumption, the proposed auto-PSD and coherence function models of wind turbulence relative to a moving vehicle are all highly in accordance with the numerical solutions, which are calculated based on only the time histories of fluctuating wind speeds relative to a moving vehicle. However, there are large differences between the results of the auto-PSD and coherence functions obtained from the previous models and the results obtained from the corresponding numerical solutions. These differences can be attributed to the fact that the previous models adopted either Taylor's frozen turbulence hypothesis or the isotropic turbulence assumption, or both. The proposed auto-PSD model and coherence function model of wind turbulence relative to a moving vehicle could provide a foundation for considering the effects of crosswinds on moving vehicles in terms of unsteady aerodynamic forces, ride comfort and running safety. • New general analytical models for correlation and power spectral density functions relative to a moving vehicle without the use of Taylor's frozen turbulence hypothesis or the isotropic turbulence assumption were proposed. • Auto-PSD calculation models relative to a moving vehicle with two different coherence functions relative to the ground were deduced. • A direct generating scheme which can more efficiently generate the time histories of fluctuating wind speeds relative to a moving vehicle was developed. • A new coherence function model of wind turbulence relative to a moving vehicle was proposed. • The accuracies of the proposed auto-PSD and coherence function models relative to a moving vehicle were systematically validated. [ABSTRACT FROM AUTHOR]

Highlights • Use an equipped two-axle test vehicle to identify the damping ratio of a simply supported beam. • Reveal the attenuation trend due to the damping effect on the scanning point response by an analytical analysis. • Present a simple, theoretical framework for computing the bridge damping ratios from the scanning points. • Verify the theory for ranges of vehicle speed, vehicle damping, bridge damping, road roughness and environment noise. Abstract A simple, theoretical framework is presented for identifying the damping ratios of simply supported beams using a two-axle moving test vehicle, equipped with uniformly spaced accelerometers and laser sensors. The latter are used to measure the relative displacements of the facing (moving) contact points on the beam, referred to as the scanning points. By adopting proper assumptions, closed-form solutions are derived for the responses of the beam and scanning points. In parallel, the scanning-point response is also given in discrete form for field applications. The road roughness effect is alleviated by using the residual response obtained as the difference of the responses of two consecutive scanning points. By utilizing the attenuation nature in the responses between two separate scanning points due to time lag, the damping ratio of the beam is derived in closed form using the Hilbert transformation. The framework proposed is verified by a finite element analysis with basically no assumptions. Its robustness is also tested for different ranges of parameters, including vehicle speed, vehicle damping, road roughness and environment noise. [ABSTRACT FROM AUTHOR]

Highlights • Formulation for beam-vehicle-elastic foundation dynamic system is given. • All the randomness in the three parts of the system is taken into account. • Numerical generation of the random variables and fields, and then applied to MCS. • Variability and statistical features of responses of the system are estimated. Abstract This paper investigates the variability of dynamic responses of a beam resting on an elastic foundation, which is subjected to a vehicle with uncertain parameters, such as random mass, stiffness, damping of the vehicle and random fields of mass density, and the elastic modulus of the beam and stiffness of elastic foundation. The vehicle is modeled as a two-degree-of-freedom spring-damper-mass system. The equations of motion of the beam was constructed using a finite element method. The mass and elastic properties of the beam, and the stiffness of foundation are assumed to be Gaussian random fields and were simulated by the spectral represent method. Masses, stiffness of the spring, and the damping coefficient of the vehicle are assumed as Gaussian random variables. The numerical analyses were performed using the finite element method (FEM) in conjunction with the Monte Carlo simulation (MCS). The variability of dynamic responses of the beam were investigated with various cases of random parameters. For each sample, the equations of motions were solved with the Wilson-q integral method to find dynamic responses. The influence of random system parameters and their correlation on the response variability is discussed in detail. [ABSTRACT FROM AUTHOR]

Highlights • This paper proposes a novel two-phase damage detection method for structures under a moving load. • The proposed method utilizes both wavelet signal processing and wavelet finite element model for damage detection. • The proposed method consists of two sequential phases, namely localization and quantification. • The proposed method is successfully validates it via a laboratory experiment of a scaled beam structure. Abstract This paper proposes a damage detection method with two phases, namely, localization and quantification, for beam structures subjected to moving load and successfully validates it via a laboratory experiment. Firstly, the discrete wavelet transform (DWT) is applied to decompose the displacement response change induced by a moving vehicle and locate potential structural damages. Then adaptive-scale wavelet finite element model (WFEM) updating is employed to estimate the damage severity in the identified damage regions in a progressive fashion. The elemental scales of WFEM are adaptively changed according to not only the moving vehicle position but also the progressively identified damage regions. Such a method can effectively minimize the number of modeling degree-of-freedoms (DOFs) and updating parameters during optimization. The feasibility and effectiveness of the proposed method is examined through a laboratory experiment with different damage scenarios. The results indicate the proposed method can achieve good consistency between structural modeling, damage scenarios, and load conditions, as well as an optimal tradeoff between damage detection accuracy and efficiency. [ABSTRACT FROM AUTHOR]

Highlights • Offer a complete coupled vibration theory for the suspension footbridge. • Interpret modal coupling mechanism of slender suspension footbridges. • Identify the key parameters dominating the flexural/torsional coupled modes. • The added stiffness of the tensile cables and wind guys can raise the first symmetric frequencies in the lateral and torsional directions. Abstract In this paper, the modal coupling mechanism is studied of a single-span footbridge consisting of a suspended beam (i.e., bridge deck), two suspension cables (via hangers) and two wind guys (via wind ties). To start, the governing equations for the slender suspended beam are derived based on the linearized deflection theory for classical suspension bridges, which is followed by two parts. First, the free vibration analysis is conducted to obtain the modal frequencies and modal shapes of the suspended beam by Galerkin's method, from which the key parameters dominating the flexural-torsional coupled vibrations are identified, along with measures for stiffness enhancement. Then, a virtual eccentrically moving vehicle is first attempted to scan (i.e. extract) the vibration messages of the suspended beam from a perspective that allows us to physically interpret the dominant mode of the flexural-torsional coupling of the beam in an easy way. The objective of this study is twofold: first to offer a complete nonlinear vibration theory for the suspension footbridge, and second to physically interpret the complicated mechanism of coupling involved. [ABSTRACT FROM AUTHOR]

The instantaneous amplitude squared (IAS) of the driving component of the contact-point response of a moving test vehicle was proposed for the damage detection of the sustaining bridge. As a supplement to the properties previously presented for the IAS, this paper is aimed at unveiling the key feature of the discontinuity amplification inherent in the IAS through the double guarantee of a "square operation" in the definition and a "second derivative" in computing the contact-point response. The capability of the IAS was demonstrated with regard to the effects of the environmental noise, vehicle damping and bridge damping in the numerical simulation. It is confirmed that the IAS can be reliably used in the damage detection of bridges by a moving test vehicle. [ABSTRACT FROM AUTHOR]

The article describes determined relationship between transport wireless network throughput and vehicle’s velocity. It is determined that such relationship is most precisely described by quadratic polynomial function, which was obtained by processing experimentally measured data and approximating them with various functions. When evaluating network’s throughput with “application layer” and “transport layer” software, the highest layer overheads can be determined. As it was stated, they form a great part of transmitted traffic. It must be considered in practice, because network’s throughput cannot be determined only by measurements of OSI Layer 3 or Layer 4 throughput. [ABSTRACT FROM AUTHOR]