Narrow Results

A semi-floating cable-stayed bridge can swing longitudinally to absorb seismic energy in an earthquake for the purpose of reducing structural response. However, the large transverse (lateral) seismic response of such large-span cable-stayed bridges must be controlled to avoid severe bridge damage and ensure train safety. This study investigates the dynamic response and associated damping mechanism of a coupled high-speed rail (HSR) vehicle and cable-stayed bridge system subjected to various ground motions. A comprehensive vehicle–track–bridge interaction system is first established. Then, the dynamics of a semi-floating cable-stayed bridge-HSR vehicle system equipped with magnetorheological bearings (MRBs) and fluid viscous dampers (FVDs) is examined with various inputs of near-fault (NF) pulse-type, NF non-pulse-type, and far-field (FF) ground motions. To effectively mitigate the bridge internal force response and enhance train running safety, the transverse and longitudinal FVDs need to be concurrently utilized along with MRBs. This research presents a novel mitigation approach for simultaneously reducing the transverse vibrations of cable-stayed bridge and the derailment risk of running train.

This study employs the wave dispersion relation of periodic structures to demonstrate the dual resonance mechanism occurring as a train traverses a series of bridges. Dual resonance occurs when the resonant speeds of both the train and the bridge coincide, leading to resonance in the bridge and progressively amplifying the train’s responses from the front to the rear carriages. This phenomenon involves a complex interaction between the bridge’s temporal resonance and the train’s spatial periodicity. This interaction creates a unique spatiotemporal vibration pattern. To understand the wave dispersion in this periodically coupled system, we model it as two interconnected spring-mass systems connected by contact springs. The analytical approach allows us to identify the key parameters governing the wave dispersion relation and wave-transmitting phenomena between two periodic structures. The wave dispersion analysis reveals that continuous beams have broader passbands, allowing them to transmit more waves and vibrations from moving trains than simply supported beams. This reduces resonance and leads to smoother system performance for continuous beams. Consequently, when a train travels on an equal-span continuous bridge at its resonance speeds, its vibrations can be efficiently transmitted to the bridge through these passbands, thereby mitigating resonance.

This paper is concerned with a numerical study on the dynamic response of a high-speed rail (HSR) system subjected to unsupported sleepers using the moving element method (MEM). A three-phase computational scheme in conjunction with the MEM is proposed to account for the motion of the unsupported sleepers in relation to the truncated rail segment in the moving coordinate system. The accuracy of the proposed computational scheme is examined by comparison with available analytical results in the literature and against the finite element method using commercial software. A parametric study is conducted using a computational model consisting of a 10-degree of freedom train model and a three-layer ballasted track model to investigate the effect of unsupported sleepers on the dynamic response of the HSR system. Various factors affecting the response of the HSR system, including the speed of the train, the number of unsupported sleepers and the distance between the unsupported sleepers, are examined and discussed.

In a railroad wagon, the vertical excitation on the wheels originated from the track irregularities; the air spring model is reliably used to restrict these abnormal vibrations at a required level and improve traveler comfort. When air springs deflate during running, too much vibration occurs and the ride is less comfortable, which are common complaints among high-speed rail operators. In the situation that the air spring deflates, the laminated rubber spring acts as a temporary emergency spring to reduce the dynamic load. An approximation method for measuring laminated rubber’s static stiffness is presented and examined the effect on the air suspension. In this study the equations of motion for the pitch, roll, and the bounce motion of the bogies and the car’s body were developed with deflated state of air spring to systematically study the effect of deflated air spring on the ride comfort of passengers. The study show that passengers’ ride comfort was predicted accurately by the proposed model. It also observed that in the presence of a laminated rubber spring, the air spring’s dynamic stiffness is moved to higher frequencies. The air spring’s dynamic stiffness is reduced at lower frequency when the diameter of the surge pipe is increased. According to the results of the research, the vehicle’s speed should be reduced while the air spring is deflated in order to keep the passengers’ comfort.

In this paper, we study the key factors affecting China’s high-speed rail development using a case study methodology and following the perspective of catch-up cycles. In addition to factors such as windows of opportunities and responses identified in the extant literature, we found that the focal organization’s strategic intent is the most important driving force. Strategic intents, opportunities, and responses, all change over time. This finding has important theoretical implications, and indicates the importance of effective coordination by the focal organization in the process of catching up in complex technology systems such as high-speed rail.

As the historical symbol behind China’s 21st century development strategy of the Belt & Road Initiative (BRI), the notion of the Silk Road(s) was never that of one singular passageway, but a network of contacts across the Eurasian continent, over both land and water. For more than two millennia, commerce, conquests, and diplomatic activities took place across this trans-continental network, bringing with them people, commodity, and ideas. In this paper, I will discuss how historical cultural spheres crossed over where the Silk Road(s) linked one group of people to another, promoting regional connectivity and co-prosperity. Using specific objects as case study, the Hoxne pepper pot and Roman glass bowls demonstrate how, as early as the Roman period, the Chinese central kingdom was already in contact with the Roman empire. Material cultural contact and adaptation was never a one-way trend, but always with ramifications to be experienced in the everyday life of all the peoples involved. Since its inception, the Silk Road(s) existed for, and in turn, benefited from, speed and efficacy in the transportation of people and goods. As the era of camels, horses, and sailing ships fades into history, China’s push for the development of high-speed rail emerges to be the most efficient and favored mode of transportation to realize true regional connectivity for BRI to kick into action.

Wall condensation phenomenon of car body of the high-speed rail has a great influence on train operation safety and air conditioning load. However, due to the complexity of condensation mechanism, it is difficult to analysis car wall condensation process from pure theory. Experiment method is adopted in this paper to study the phenomenon, and the corresponding results are obtained, which is beneficial to the optimization design and running of car.

As a modern means of transport, high-speed rail has a significant influence on the transformation and upgrading of economic and sustainable development. This paper mainly elaborate the impact from four aspects, which including the macroeconomic management, the regional economic development, the spatial economic landscape and the optimization development of the industry, so as to sum up and analyze the impact on economic about the existing literature. Finally, proposing the prospects for the future research in connection with the problems of the existing research.