Traffic-induced Vibrations Research Articles

Full scale monitoring of wind and traffic induced response of a suspension bridge

This paper presents a full-scale analysis of wind and traffic-induced vibrations of a long-span suspension bridge in complex terrain. Several wind and acceleration sensors have been installed along the main span on Lysefjord Bridge in Norway. In the present study, three days of continuous records are analysed. Traffic-induced vibrations are dominant at low and moderated wind speed, with non-negligible effects on the overall bridge response for heavy vehicles only. Traffic and wind-induced vibrations are compared in terms of root mean square of the acceleration response, and three simples approaches are proposed to isolate records dominated by wind-induced vibration. The first one relies on the separation of nocturnal and diurnal samples. The second one is based on the evaluation of the time-varying root mean square of the acceleration response. The last one evaluates the relative importance of the high frequency domain of the acceleration bridge response. It appears that traffic-induced vibrations may have to be taken into account for the buffeting analysis of long- span bridge under moderated wind.

Piezoelectric energy harvesting from traffic-induced pavement vibrations

This paper focuses on the development and experimental testing of a potential clean energy source for powering the remote equipment used in transportation infrastructure. Traditional power sources (i.e., power cables and batteries) are excessively expensive or infeasible in this type of application. A compression-based roadway energy harvester has been developed that can be embedded into pavement to scavenge electrical energy from traffic-induced vibrations. The proposed roadway harvester employs a group of piezoelectric harvesting units to convert traffic-induced vibrations into electrical energy, and each single harvesting unit contains three piezoelectric multilayer stacks. According to the linear theory of piezoelasticity, a two-degree-of-freedom electromechanical model of the piezoelectric harvesting unit was developed to characterize its performance in generating electrical energy under external excitations. Experimental testing in the laboratory was conducted to investigate the output power properties of the harvesting unit and shows good agreement with the theoretical analysis. Based on the testing results of the harvesting unit, the capability of the proposed roadway harvester has been theoretically evaluated and demonstrated that it has the ability to generate sufficient energy for driving common electrical equipment used in transportation infrastructure.

Reduction in ground vibrations by using shaped landscapes

Reduction in traffic-induced ground vibrations by the use of shaped landscapes is investigated here by shaping the landscape surrounding a high-tech facility, using the landscape thus produced as a wave obstacle. The effects of the geometric parameters of a shaped landscape were examined in parametric studies. An architectural landscape design was also investigated in terms of its effectiveness in reducing traffic-induced ground vibrations. Finite element models, analysed in the frequency domain, were employed. The models involve a layer of soil and the underlying bedrock. It was found that anywhere from an appreciable reduction to an appreciable amplification of the vibrations produced can occur, depending upon the geometric parameters of the shaped landscape involved. The most effective shape was found for a topography that acted as a waveguide that reduced the level of vibration by approximately 35%.

Field Monitoring of Rebar Debonding in Concrete Bridge Decks under Traffic-Induced Vibrations

Concrete deck resurfacing is conducted through staged construction under active traffic conditions in lanes adjacent to the newly poured concrete. Many engineers are concerned about the potential of cracking and rebar debonding and other factors, such as shrinkage, thermal expansion and contraction, and live loads. There is a need to evaluate these detrimental effects with techniques that are reliable under field conditions. In this paper, results are presented from a field study that measured peak rebar velocities during concrete pours. The peak velocities were then compared with experimentally established limits for the cracking potential of the concrete surrounding the rebar. However, it is often more feasible to process accelerometer measurements to obtain velocity indirectly from common processing techniques, such as direct integration. A numerical approach was developed to mitigate the various sources of error in the integration and produce accurate estimates of velocities and displacements from raw accelerometer data. The comprehensive field testing of a rehabilitated bridge span was conducted to capture the dynamic response of the bridge girders, stringers, and deck reinforcement. The bridge was monitored during the pour of a simple span and for several hours after the initial concrete placement. The response predicted by the numerical analysis compared well with the field results: the time histories of velocity and displacement were accurately reconstructed. A comparison with the established limits of peak particle velocity suggested that vibrations induced by typical truck traffic during the initial concrete setting period should not pose any significant risk of debonding.

Experimental Evaluation of Vibration Effects Induced by Planed Railway Line on Surrounding Historic Tower

Using field experiments, the vibration effects of historic tower induced by planed railway line are estimated. The vibrations include the construction vibration and the traffic-induced vibration. The results show that the blasting construction leads to the significant increase in vertical velocity and acceleration. There is no difference between the background vibration of field and foundation of tower. Different types of the sites soil around the tower cause little change. Each measurement time showed an upward trend of vibration level with the increase of frequency. The closer the tower is to the vibration source, the larger the structural vibrations would be. The dominant frequency range for highway-induced vibration is 10-20Hz. For train-induced vibration, the dominant frequency range is more than 40Hz. Surface waves will result in amplification phenomenon of vibration velocity of ancient structures within a certain range.

The Impact of Traffic-Induced Bridge Vibration on Rapid Repairing High-Performance Concrete for Bridge Deck Pavement Repairs

Based on forced vibration tests for high-performance concrete (HPC), the influence of bridge vibration induced by traveling vehicle on compressive strength and durability of HPC has been studied. It is concluded that 1 d and 2 d compressive strength of HPC decreased significantly, and the maximum reduction rate is 9.1%, while 28 d compressive strength of HPC had a slight lower with a 3% maximal drop under the action of two simple harmonic vibrations with 2 Hz, 3 mm amplitude, and 4 Hz, 3 mm amplitude. Moreover, the vibration had a slight effect on the compressive strength of HPC when the simple harmonic vibration had 4 Hz and 1 mm amplitude; it is indicated that the amplitude exerts a more prominent influence on the earlier compressive strength with the comparison of the frequency. In addition, the impact of simple harmonic vibration on durability of HPC can be ignored; this shows the self-healing function of concrete resulting from later hydration reaction. Thus, the research achievements mentioned above can contribute to learning the laws by which bridge vibration affects the properties of concrete and provide technical support for the design and construction of the bridge deck pavement maintenance.

Motor Vehicle Traffic-Induced Vibration Characteristics of the Ground and Urban Pedestrian Overpass

Since the 21st century, Beijing accelerate the process of internationalization. The level of the construction of Beijing city also faced a new challenge. The city traffic problems in Beijing is badly in need of improving. The stiffness of pedestrian bridge is so low that produce large vibration in the influence of ground traffic, which has a psychological effect on the pedestrian, even may cause psychological panic, anxiety and other adverse reactions. This study by monitoring the footbridge vibration at Beijing City Garden Road ,establishing finite element model to know about its severity under Motor vehicle traffic loads to get Vibration mechanics parameters. Use ISO, UK, Japan bridge design specifications and standard to check to make a scientific and reasonable evaluation on the vibration comfort about it.

Analiza vibracija okvirnih konstrukcija uzrokovanih prometom

A simple numerical model for the dynamic analysis of 2D frames in the frequency domain, based on the Spectral Element Method (SEM), is presented in the paper. The influence of soil-structure interaction is taken into account. The dynamic stiffness of rigid foundations is determined by the Integral Transform Method (ITM). Three frames with a different number of storeys are analyzed with respect to vibrations caused by tram and road traffic. The influence of the soil-structure interaction on natural frequencies and amplitudes of vibrations is considered. The assessment of the way in which humans are affected by traffic-induced vibrations is conducted according to British Standard BS:6472.

Dynamic Characteristics of a Multi-Functional Bridge Bearing with Built-In Piezocomposite Element

A multi-functional bridge bearing with built-in piezocomposite electricity generating element (PCGE) is being developed by our research team to respond to the growing demand of self-powered sensing devices for the monitoring of bridges by harvesting the energy produced by the traffic-induced vibrations. For the intended application, a multilayered piezoelectric PCGE structure composed of layers of piezoceramic, glass/epoxy, and carbon/epoxy, has been developed to improve the durability, output voltage and power of the piezoceramic. The output voltage of this PCGE can be used for real-time traffic monitoring like in bridge-weigh-in-motion systems and can eventually be exploited to generate the electricity needed for the lighting and functioning of other embedded sensors. This paper presents the results of the dynamic loading tests conducted on a prototype of the proposed multi-functional bridge bearing to enhance its design details and verify the accuracy of the measurement. The results show that the bearing provides reliable measurement for traffic monitoring and enable to conceive details for the improvement of the output voltage of the PCGE. Since bridge bearings, as indispensable devices transferring the loads and movements from the deck to the substructure and foundations of the bridge, are continuously subjected to traffic loads, the proposed bridge bearing appears to be a natural and economic solution that can be applied to existing or newly built bridges without modification of the conventional design while providing additional and valuable functions for the maintenance of the structure.

Reply to the Discussion by Chen on “Traffic-induced vibrations of frame structures”

We agree with the discusser's observation that the largest displacement of a twelve-storey frame occurs at the fourth storey under the tram traffic. However, the largest horizontal displacements of a six-storey frame occur at the top floor under both tram and truck traffic (Fig. 14 in the paper). In addition, the largest horizontal displacement of a twelve-storey frame under the truck traffic also occurs at the top floor. Horizontal displacement spectra of six and twelve storey frames are given in Figs. 1–4. Obviously, the largest displacement amplitudes occur at the lower horizontal vibration modes for both six and twelve storey frames (Table 1).

Discussion of “Traffic-induced vibrations of frame structures” 1Appears in the Canadian Journal of Civil Engineering, 2013, 40(2): 158–171. [doi:10.1139/cjce-2011-0247

Discussion of “Traffic-induced vibrations of frame structures” ¹Appears in the Canadian Journal of Civil Engineering, 2013, <b>40</b>(2): 158–171. [doi:10.1139/cjce-2011-0247

Piezoelectric energy harvesting from traffic-induced bridge vibrations

This paper focuses on energy harvesting from traffic-induced vibrations in bridges. Using a pre-stressed concrete highway bridge as a case study, in situ vibration measurements are presented and analysed. From these results, a prototype of a cantilever piezoelectric harvester is designed, tested and modelled. Even though the considered bridge vibrations are characterized by small amplitude and a low frequency (i.e. below 15 Hz), it is shown that mean power of the order of 0.03 mW can be produced, with a controlled voltage between 1.8 and 3.6 V. A simple model is proposed for theoretical prediction of the delivered power in terms of traffic intensity. This model shows good agreement with the experimental results and leads to a simple but effective design rule for piezoelectric harvesters to be used on bridges.

Application of the Hilbert-Huang Transform for Identification of Changes in Boundary Conditions of a Bridge Using Vibration Data due to Traffic

The translational restraints associated to pin and rocker bearings are typically idealized in the form of fixed and free conditions. However, elastomeric bearings need to be represented with springs to reasonably predict the time- and frequency-domain response of bridges under traffic-induced vibrations. Therefore, changes in the response of these bearings are common as a result of aging, deterioration, variation in loading levels and/or environmental changes. The latter makes difficult to discern if changes in the frequency content of the structural response to ambient vibration are due to changes in temperature, changes in normal operational loads or the occurrence of damage. In this paper, the bridge is idealized by a beam model supported on a hysteretic translational sprung support. The purpose is twofold: (a) to gather a better understanding of the variations of the bridge response with bearing performance; and (b) to be able to quickly identify an anomaly in the bearing. Empirical Mode Decomposition and the Hilbert-Huang Transform are employed to capture changes in the bearing stiffness from the bridge response.

Electromagnetic energy harvester with repulsively stacked multilayer magnets for low frequency vibrations

This paper investigates the applicability of an electromagnetic generator with repulsively stacked magnets for harvesting energy from traffic-induced bridge vibrations. First, the governing equation for electro-mechanical coupling is presented. The magnetic field for repulsive pole arrangements is discussed and the model is validated from a magnet falling test. The detailed design, fabrication, and test results of a prototype device are presented in the paper. An experimental vibration shaker test is conducted to assess the performance of the energy harvester. Field test and numerical simulation at the 3rd Nongro Bridge in South Korea shows that the device can generate an average power of 0.12 mW from an input rms acceleration of 0.25 m s−2 at 4.10 Hz. With further frequency tuning and design improvement, an average power of 0.98 mW could be potentially harvested from the ambient vibration of the bridge.

Traffic-induced vibrations of frame structures

Using the spectral element method (SEM), a 2-D numerical model of multi-storey frame structures has been developed. The model has been used to predict traffic-induced vibrations of two, six, and twelve-story concrete buildings measured along the route of a future metro line in Belgrade, the capital of Serbia. Vibration simulations of the six-storey frame match satisfactorily the measured dynamic response. However, there is a difference between numerical simulation and the actual measurements for the two-storey and twelve-story buildings. The results indicate a great potential of the proposed SEM to simulate ground-induced vibrations of frame buildings. However, more complex structural models should be developed to better replicate actual situations.

Linear system parameter as an indicator for structural diagnosis of short span bridges

This paper intended to investigate the feasibility of bridge health monitoring using a linear system parameter of a time series model identified from traffic-induced vibrations of bridges through a laboratory moving vehicle experiment on scaled model bridges. This study considered the system parameter of the bridge-vehicle interactive system rather than modal ones because signals obtained under a moving vehicle are not the responses of the bridge itself but those of the interactive system. To overcome the shortcomings of modal parameter-based bridge diagnosis using a time series model, this study considered coefficients of Autoregressive model (AR coefficients) as an early indicator of anomaly of bridges. This study also investigated sensitivity of AR coefficients in detecting anomaly of bridges. Observations demonstrated effectiveness of using AR coefficients as an early indicator for anomaly of bridges.

Field measurements of traffic-induced vibration of straddle-type monorail PC girder viaducts

Field measurements of traffic-induced vibration of straddle-type monorail PC girder viaducts

Impact assessment of traffic-induced vibration on natural gas transmission pipeline

The purpose of this paper is to present a study of impact assessment of the traffic-induced vibration on a buried natural gas transmission pipeline. The basic assumption in this study is that the traffic on pipeline-transportation route crossing might have a significant impact on natural gas pipeline structural integrity due to the traffic-induced vibration which propagates from the road surface through the soil and excites the buried natural gas pipeline. The resulting dynamic stress causes pipeline material fatigue loading which consequently may cause pipeline failure with the gas release into the environment exposing the population and the buildings in pipeline vicinity to a significant threat. The experiment on operating buried natural gas pipeline was conducted where measurements were performed on the road surface, the two operating buried natural gas pipelines of external diameter 500 mm and 250 mm and on corresponding casing pipes. The measurement data analysis was performed and the results were used for determination of pipeline lifetime period in the model for theoretical estimation of pipeline lifetime which has been exposed to traffic-induced vibration. The findings of the study in this paper show that the traffic-induced vibration on given buried natural gas pipeline is detectable, however this vibration, compared to the other factors which are influencing pipeline's structural integrity, does not have a significant impact on pipeline lifetime period.

Discussion on the paper entitled: Numerical modeling of traffic-induced ground vibration

Discussion on the paper entitled: Numerical modeling of traffic-induced ground vibration

Numerical modeling of traffic-induced ground vibration

Ground vibrations due to road traffic constitute a major environmental problem. This paper presents a numerical model for the analysis and prediction of the ground vibrations due to the road traffic. A car model with four degrees of freedom is used for the determination of the load due to the road traffic. The load is then introduced in a 3D finite difference model for the determination of the traffic-induced ground vibrations. The numerical model is validated using field data. Numerical analyses show that both the amplitude and frequency of the traffic-induced vibrations are mainly affected by the vehicle speed, the road unevenness and the vehicle suspension system. Some recommendations are suggested for the reduction of these vibrations.