Developing a New Vibration Analysis Calculative Method for Esfahan Subway Train and Railways Design, Manufacturingand Construction

Omid A. Zargar
Page No. 30-40

The simulated mass and spring evaluationfor subway or railways construction and installation
have wide applications in rail industries. This kind of design should be optimize all related
parameters to reduce the amount of vibration in cities, residential areas, historical zones and other
critical locations. Finite element method is used too much to analyze such applications with an
excellent accuracy but developing some simple, fast and user friendly evaluation always was
required in subway industry. In addition, process parameter optimization are required in railways
to achieve optimal railways design with maximum safety, reliability and performance. The simple
but useful simulated mass and spring evaluation system is developed for Esfahan subway
construction. This method is discussed in this paper. Esfahan subway construction has a historical
zone. Historical buildings should be protected from harmful vibrations. Polyurethane layer is used
to reduce vibrations. This layer completely covered by concrete layers in all directions. It is worthy
to know that, all the operation criteria like displacement and stress could be adapted with all
vibration criteria like natural frequency, operation frequency and damping. Adaptation is
performed by changing in polyurethane layer thickness. The results showed that if 25 millimeter
thickness polyurethane layer covered completely by two concrete layers with 12 millimeter
thickness,the amounts of vibrations reduce considerably. In addition, it is strongly recommended to
increase the polyurethane layer up to 37 millimeter in historical zone to prevent potential harmful
effects. The results is confirmed by other commercial methods. The calculative method is
successfully performed.Furthermore, it is important to reduce maintenance costs in any potential
design.The process parameter like rail ways dimension, rail ways material, cabins loading, cabins
quality, cabins dimension and polyurethane layer thickness properly designed to keep the subway
natural frequency around 18 Hz ( less than allowable 20 Hz).Numerical design results will protect
all historical buildings, palaces paintings and old bridges in future subway operation times. In
addition, some interesting patent and innovation in rail industry like Suspension mass tuned
vibration reducer, short sleeper vibration attenuation fastener and Airtight track vibration noise
reducing fastener are discussed in this paper.
Keywords—Subway construction engineering, natural frequency, operation frequency, vibration
analysis, polyurethane layer.