Search

Over-track buildings in metro depots become more and more prevalent in metropolis with the increase in population and the decrease of construction land. However, the train-induced vibration greatly reduces the comfort of occupants living in the over-track buildings. Owing to complex vibration sources and numerous transfer paths, it is a challenging task to analyze and predict the vibration characteristics accurately in the building. In this paper, a field measurement campaign of vibration was conducted in the Guanhu metro depot in Guangzhou, China. A novel formulation based on the operational transfer path analysis (OTPA) and singular value decomposition (SVD) is proposed to analyze the measured data and predict the train-induced vibration in the building. In this study, the vibration contributions from each transfer path to the target points in the building were obtained and the predominant transfer paths were identified further. Besides, the vibration at target points in the building was predicted using the vibration at path points and transmissibility functions from transfer paths. This study provides insights into the prediction and evaluation of vibration transmissions from vibration source to upper floors of over-track building. [ABSTRACT FROM AUTHOR]

Abstract: This study presents a statistical analysis of GPS L-band scintillation with data observed from July 2008 to March 2012 at the northern crest of equatorial anomaly stations in Guangzhou and Shenzhen of South China. The variations of the scintillation with local time, season, solar activity and duration of scintillation patches were investigated. The relationship between the scintillation and TEC depletion was also reported. Our results revealed that GPS scintillation occurred from 19:30 LT (pre-midnight) to 03:00 LT (post-midnight). During quiet solar activity years, the scintillation was only observed in pre-midnight hours of equinox months and patches durations were mostly less than 60min. During high solar activity years, more scintillation occurred in the pre-midnight hours of equinox and winter months; and GPS scintillation started to occur in the post-midnight hours of summer and winter. The duration of scintillation patches extended to 180min in high solar activity years. Solar activity had a larger effect to strong scintillations (S4 >0.6) than to weak scintillations (0.6⩾S4 >0.2). Strong scintillations were accompanied by TEC depletion especially in equinox months. We also discussed the relationship between TEC depletion and plasma bubble. [Copyright &y& Elsevier]