نتایج جستجو برای: railway track supporting media
تعداد نتایج: 479676 فیلتر نتایج به سال:
one of the most important challenges in the development of urban railways network is the effects of railway vibrations on human and adjacent structures. although various investigations into the sources of railway vibrations have been conducted, very few research works have been reported on the influences of track geometry parameters on the level of vibrations. this is addressed in this research...
Development of an optimized strategy for the maintenance of Iranian railway track maintenance in a form of management system was made in this research. Through reviewing the current maintenance management system in the USA, Europe and Asia as well as investigating the characteristics of railway structure and current maintenance approaches in Iran, a new algorithm was made in order to improve ef...
Construction of railway track embankment over a soft subgrade will bring the necessity of using soil improvement methods for bearing capacity and settlement criteria satisfaction. As a practical improvement method, railway embankment filled with geofoam blocks is studied in this paper. First; a bilinear stress-strain model developed in FLAC2D to simulate geofoam embankment behavioral model. Sec...
Railway maintenance planners require a predictive model that can assess the railway track geometry degradation. The present paper uses a hierarchical Bayesian model as a tool to model the main two quality indicators related to railway track geometry degradation: the standard deviation of longitudinal level defects and the standard deviation of horizontal alignment defects. Hierarchical Bayesian...
Thorough understanding of steel rail response to wheel load is a key step towards design and evaluation of the railway track structure. In current practice, maximum vertical deflection and bending moment are calculated using the theory of infinite beam on continuous elastic foundation (Winkler model), in which the foundation stiffness is assumed as constant. However, variation of track modulus ...
the vibrations produced by trains include two parts which are deterministic and random vibrations. due to variation of dynamic loads and patterns of load-time, the random vibration of moving train is one of the most important issues in the field of railway engineering. one of the important sources in producing the train vibrations is rail roughness and irregularities. in this paper, responses o...
Analysis of Railway Ballasted Track Stiffness and Behavior with a Hybrid Discrete–Continuum Approach
Abstract Railway ballasted track stiffness is an important indicator to identify supporting condition that ensures the facility well designed and functioned. Although many studies have been...
Nonlinear hunting speeds of railway vehicles running on a tangent track are analytically obtained using Hopf bifurcation theory in this paper. The railway vehicle model consists of nonlinear primary yaw dampers, nonlinear flange contact stiffness as well as the clearance between the wheel flange and rail tread. Linear and nonlinear critical speeds are obtained using Bogoliubov method. A compreh...
critical thinking ability has an important role in education. accordingly, scholars around the world are searching for new ways for teaching and improving students critical thinking ability. in line with the studies in efl contexts supporting the positive relationship between critical thinking and writing performances, this study investigated the differential effects of halverson’s critical thi...
Bicycling crashes on streetcar (tram) or train tracks: mixed methods to identify prevention measures
BACKGROUND Streetcar or train tracks in urban areas are difficult for bicyclists to negotiate and are a cause of crashes and injuries. This study used mixed methods to identify measures to prevent such crashes, by examining track-related crashes that resulted in injuries to cyclists, and obtaining information from the local transit agency and bike shops. METHODS We compared personal, trip, an...
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