Experimental Study on Pre-Excavation of Wuzhun Railway Bridge Affected by Shield

2018 ◽  
Vol 07 (06) ◽  
pp. 919-928
Author(s):  
军 施
2022 ◽  
Vol 220 ◽  
pp. 104879
Author(s):  
Huoyue Xiang ◽  
Hao Hu ◽  
Jin Zhu ◽  
Peng He ◽  
Yongle Li ◽  
...  

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7964
Author(s):  
Lucjan Janas

The paper presents the results of vibroacoustic tests of a plate girder railway bridge consisting of two parallel dilated structures and a common ballast trough. The requirements currently set for railway bridges relate to, among others, vibrations considered as one of the criteria for traffic safety and to noise emissions that may pose a threat to the environment. In this article, the results of tests conducted on vibrations of elements of the analyzed structure are presented, and the level of these vibrations in terms of meeting the requirements of the European standards is assessed. Vibrating criteria of structure performance were checked, and safety was assessed. The results of noise measurements in the vicinity of the analyzed bridge are also presented, and the environmental impact of this structure is determined. The test results show that the bridge meets the requirements for vibration acceleration and noise. An increased acoustic emission in the analyzed case does not pose a significant threat, but if this type of structure was on high supports in an urbanized area, it would be a nuisance to the environment.


2011 ◽  
Vol 90-93 ◽  
pp. 964-968
Author(s):  
Xue Min Li ◽  
Er Yu Zhu ◽  
Yong Zheng Zhou ◽  
Yue Hong Qin

Due to the usage of high-strength concrete, excessive hydration heat is generated in the whole span box girder of high-speed railway. The maximum allowable temperature should not exceed 60°C according to the Technical Guide on Railway Bridge Construction of Passenger Dedicated Line. However, according to the field measurement and simulation to the maximum temperature of box girder concrete, we find that the maximum hydration temperature of concrete is generally more than 60°C which is the limited value of the specification. The research results show that the limited value of maximum hydration temperature for box girder concrete can be relaxed to 65°C.


Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.


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