scholarly journals The acoustic specificity of steel-railway bridges

2017 ◽  
Vol 2017 (9) ◽  
pp. 38-45
Author(s):  
Lucjan Janas
Keyword(s):  
Acoustic Pressure ◽  
The Other ◽  
Railway Bridges ◽  
Deck Plate ◽  
Steel Deck

In the paper, the acoustic effects in the vicinity of four railway bridges have been studied. One of the objects has a track fastened directly to the steel deck plate, another has a deck in the form of an open grillage. The other two objects have a track situated on the ballast and various types of girders. The influence of the bridge on the level of acoustic pressure in the neighborhood of railway roads has been analyzed. General recommendations for the design of silent bridges were discussed.

Can 100-year-old steel railroad bridges continue to be used in service?

2019 ◽  
Author(s):  
Anna M. Rakoczy ◽  
Duane Otter
Keyword(s):  
Probabilistic Method ◽  
Probabilistic Methods ◽  
Steel Bridge ◽  
Accurate Assessment ◽  
Railway Bridges ◽  
Railroad Bridges ◽  
Service Testing ◽  
Deck Plate ◽  
Steel Deck ◽  
Plate Girder

<p>More than 50 percent of steel deck plate girder railway bridges in North America exceed 100 years in service. This includes more than 14,000 spans with a total length of 145 miles that remain in service. The oldest bridges are close to 150 years old. For these aging structures, there is a special need to develop reliable procedures to evaluate their fitness for continued service. Simplified calculations and conservative assumptions often lead to spurious outcomes that indicate older structures ceased to be functional decades ago. Even if a steel bridge reaches its estimated fatigue life, the structure might be fit for future service and perhaps for a significant period of time. Fitness for service assessments that utilize probabilistic methods, and that are informed by and consistent with detailed physical inspections of the structures, provide a more accurate assessment of the fitness and expected life of bridges. In this paper, a probabilistic method is demonstrated on three, riveted deck plate girder spans that exceed 100 years of service. The spans are currently located at the Facility for Accelerated Service Testing.</p>

Design of the Murray and Wolverine River rail bridges

1984 ◽  
Vol 11 (4) ◽  
pp. 701-708 ◽  
Author(s):  
G. W. Taylor
Keyword(s):  
Single Cell ◽  
Key Words ◽  
Continuous Steel ◽  
Box Girder ◽  
Railway Bridges ◽  
Branch Line ◽  
Steel Box Girder ◽  
Deck Plate ◽  
Bridge Steel

This paper describes the design of the Murray and Wolverine River rail bridges, two of the largest river crossings on British Columbia's Tumbler Ridge branch line. These unique railway bridges feature a single-cell, continuous steel box girder superstructure supported by pairs of steel delta legs. The top flange of the box girder is an orthotropic deck plate that is a part of the ballast containment trough. Stability of the delta legs is provided by posttensioning of their bases to the concrete substructure. Key words: rail bridge, steel box girder, steel delta legs, orthotropic deck, posttensioning.

Effective Width of Steel Deck-Plate in Bridges

1969 ◽  
Vol 95 (7) ◽  
pp. 1459-1474
Author(s):  
George Abdel-Sayed
Keyword(s):  
Effective Width ◽  
Deck Plate ◽  
Steel Deck

scholarly journals Effects of Central Tube on Shape of Modal Duct of a Helicoid in a Simple Expansion Chamber

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Daniel Omondi Onyango ◽  
Robert Kinyua ◽  
Abel Nyakundi Mayaka
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Plane Wave ◽  
Acoustic Pressure ◽  
Three Dimensional ◽  
The Other ◽  
Expansion Chamber ◽  
Central Tube ◽  
Simple Expansion ◽  
Plane Wave Propagation

The shape of the modal duct of an acoustic wave propagating in a muffling system varies with the internal geometry. This shape can be either as a result of plane wave propagation or three-dimensional wave propagation. These shapes depict the distribution of acoustic pressure that may be used in the design or modification of mufflers to create resonance at cut-off frequencies and hence achieve noise attenuation or special effects on the output of the noise. This research compares the shapes of acoustic duct modes of two sets of four pitch configurations of a helicoid in a simple expansion chamber with and without a central tube. Models are generated using Autodesk Inventor modeling software and imported into ANSYS 18.2, where a fluid volume from the complex computer-aided-design (CAD) geometry is extracted for three-dimensional (3D) analysis. Mesh is generated to capture the details of the fluid cavity for frequency range between 0 and 2000Hz. After defining acoustic properties, acoustic boundary conditions and loads were defined at inlet and outlet ports before computation. Postprocessed acoustic results of the modal shapes and transmission loss (TL) characteristics of the two configurations were obtained and compared for geometries of the same helical pitch. It was established that whereas plane wave propagation in a simple expansion chamber (SEC) resulted in a clearly defined acoustic pressure pattern across the propagation path, the distribution in the configurations with and without the central tube depicted three-dimensional acoustic wave propagation characteristics, with patterns scattering or consolidating to regions of either very low or very high acoustic pressure differentials. A difference of about 80 decibels between the highest and lowest acoustic pressure levels was observed for the modal duct of the geometry with four turns and with a central tube. On the other hand, the shape of the TL curve shifts from a sinusoidal-shaped profile with well-defined peaks and valleys in definite multiples of π for the simple expansion chamber, while that of the other two configurations depended on the variation in wavelength that affects the location of occurrence of cut-on or cut-off frequency. The geometry with four turns and a central tube had a maximum value of TL of about 90 decibels at approximately 1900Hz.

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