Influence of Vibration Isolator Stiffness on the Dynamic Performance of a Steel-Floating Slab Track

The floating slab track (FST) is the most efficient structure for mitigating the vibrations caused by underground railway systems. The analytical model for the steel-floating slab track system (SFST) was developed using a conventional mathematical approach based on influence lines to calculate the deflections, vibration attenuation, and stresses. The developed system was validated through the fatigue verification test. The effect of the decrease in stiffness of the steel-spring isolator (SSI) on the dynamic performance of the slab track was analyzed and compared. It was found that the vibration attenuation efficiency of the system increases significantly as the stiffness of the SSI decreases. However, lowering the stiffness of the isolator increases the dynamic deflections and hence results in higher stresses causing the fatigue failure of the system. Although implementing the SFST with lower stiffness decreases the natural frequency, it may raise concerns regarding slab track damage. Therefore, it is necessary to evaluate the reasonable stiffness of the SSI to achieve satisfactory vibration attenuation as well as the safe design of the slab track system.