The aerodynamic characteristics of train/vehicles under cross winds depend on not only the shapes of the vehicles but also those of infrastructures. Accordingly three kinds of wind tunnel tests were made to evaluate the aerodynamic characteristics of typical configurations of the vehicles on typical configurations of infrastructures such as bridges and embankments. The main results obtained from the wind tunnel tests are summarized below. 1. The aerodynamic side force coefficient of the vehicle increases more as the thickness of the bridge girder becomes larger. It also increases more as the roof of the vehicle becomes edgier. 2. The aerodynamic characteristics of the vehicle on the embankment depend on the distribution of the boundary layer on the ground. The aerodynamic side force coefficient of the vehicle on a high embankment is larger than that on a low embankment.

Aerodynamic Characteristics of Train/Vehicles under Cross Winds

China’s high-speed railway (HSR) construction industry has been experiencing a golden period of opportunities in the recent decades. Due to the necessity of protecting arable lands and the advantage of rapid construction, bridges (elevated structures) are predominantly used in China’s HSRs, which must meet the critical small settlement requirement. This article first reviews the main technical standards of small- to medium-span HSR bridges, where their comparison with the Japanese standard and International Union of Railway standards is highlighted. Then, the long-span HSR steel bridges are described and discussed case by case. Based on the engineering practice of HSRs, the main achievements and key technologies of HSR bridges in China are provided, followed by the opportunities and challenges of the current and future developments of HSR bridges.

Recent developments of high-speed railway bridges in China

The vehicle scanning method (VSM), an indirect approach for bridge measurement, has attracted intensive attention since it was proposed. By this method, a moving test vehicle is employed to detect ...

State-of-the-Art of Vehicle-Based Methods for Detecting Various Properties of Highway Bridges and Railway Tracks

High-speed rail

Assessment of train running safety on bridges: A literature review

The vehicle scanning method (VSM), an indirect approach for bridge measurement, has attracted intensive attention since it was proposed by Yang and co-workers in 2004. This method is featured by the fact that no vibration sensors need to be mounted on the bridge, but only one or few vibration sensors are required on the test vehicle. Such an idea has been verified by the field tests, and then quickly extended to construction of mode shapes, identification of damping ratios, and detection of damages for bridges, among others. Compared with the conventional direct method that relies fully on the vibration responses recorded by sensors equipped on the bridge, the advantage of the indirect method is obvious: mobility, economy, and efficiency. Over the years, a rapidly growing number of research works have been conducted along the lines of the VSM for bridge measurement. Particularly, extensive lab experiments and field tests have been carried out worldwide to implement the VSM, resulting in numerous new findings. Moreover, while the technique is still flourishing, it is nourished by inclusion of modern devices such as smartphones, vehicular networks, and cloud. In 2018, a review paper was compiled by two of the authors. To reflect the recent rapid growth of research in this area since then, there exists a need to make an expansion to include the huge number of newly published papers (274 papers in total). As an extension of the 2018 paper, this paper represents a state-of-the-art review of the related researches conducted worldwide. Comments and recommendations will be made at proper places, while concluding remarks including future research directions will be presented at the end of the paper. 

Recent Advances in Researches on Vehicle Scanning Method for Bridges

The consideration of train-bridge system under winds has been attracted extensive attentions, but the winds are typically treated as stationary. This stationary assumption clearly presents a depart...

An efficient analysis framework for high-speed train-bridge coupled vibration under non-stationary winds

An adjustable, louver-type wind barrier was introduced in this study for improving the running safety and ride comfort of train on the bridge under the undesirable wind environment. The aerodynamic characteristics of both train and bridge due to this novel wind barrier was systematically investigated based on the wind tunnel tests. It is suggested that rotation angles of the adjustable blade of the louver-type wind barrier should be controlled within 90 to achieve an effective solution in terms of the overall aerodynamic performance of the train. Compared to the traditional grid-type wind barrier, the louver-type wind barrier generally presents better aerodynamic performance. Specifically, the larger decrease of the lift force and overturn moment of the train and the smaller increase of the drag force and torsional moment of the bridge resulting from the louver-type wind barrier were highlighted. Finally, the computational fluid dynamics (CFD) technique was applied to explore the underlying mechanism of aerodynamic control using the proposed wind barrier.

Aerodynamic performance of a novel wind barrier for train-bridge system

A novel frequency-free movable test vehicle for retrieving modal parameters of bridges: Theory and experiment

Both vehicle frequencies and road roughness are factors that may render the vehicle scanning method ineffective for bridges. In this paper, both factors will be eliminated via the skillful use of a two‐axle test vehicle. Namely, the effect of vehicle frequencies is removed by using the vehicle–bridge contact (point) responses and road roughness by the residue of the front and rear contact responses of the two‐axle test vehicle. Firstly, the contact responses for the two axles are derived from the vertical and rotational equations of motion for the test vehicle. Next, the contact response is processed by the variational mode decomposition (VMD) to yield the component response and then by the Hilbert transform (HT) to yield the mode shape. The parametric study has demonstrated that (1) more bridge frequencies can be extracted from the contact responses presented due to removal of vehicle frequencies; (2) the VMD‐HT technique for recovering mode shapes is robust with regard to vehicle damping and speed; (3) the proposed procedure in its entity is good not only for single‐span but for multi‐span bridges; and (4) the residue of the axles' responses can effectively reduce road roughness in identifying bridge modal properties.

Kang Shi

Papers

Recent Advances in Researches on Vehicle Scanning Method for Bridges

An efficient analysis framework for high-speed train-bridge coupled vibration under non-stationary winds

Aerodynamic performance of a novel wind barrier for train-bridge system

A novel frequency-free movable test vehicle for retrieving modal parameters of bridges: Theory and experiment

Using vehicle–bridge contact spectra and residue to scan bridge's modal properties with vehicle frequencies and road roughness eliminated