當交通工具行經橋梁或是高架橋時會產生振動,而這些振動可能會造成高精密儀器的誤差。這些誤差也可能造成高科技產業的產品無法使用,進而對高科技產業造成傷害。因此本研究對橋梁或高架橋底下的基樁進行改良,於基樁上加裝減振器使基樁本身就有減振能力,以求降低此類問題之影響。由前人的研究可知液壓減振器具有良好的減振效果與最大動態位移量的控制,為了在最大動態位移量可接受的範圍內求得最好的減振效果,本研究在液壓減振器內填入適量的空氣,探討減振與變形的平衡點。因此本研究將改變液壓減振器內的空氣體積,並進行一系列的模型試驗。由目前試驗結果得知,減振效果、最大動態位移量都隨著空氣填充度變大而變大。空氣填充度於0%~10%之範圍內,減振效果並未隨空氣填充度增加而明顯增加,但最大動態位移量則大幅增加。減振效果與最大動態位移量於空氣填充度10%到40%之間快速地增加。但空氣填充度大於40%之後,減振效果與最大動態位移量的變化都漸趨平緩。Vibration may be caused during vehicle passes through bridge or viaduct, and the vibration may cause some inaccuracy of products in high technology factory. Furthermore, high technology products made by these factories may be useless because of the influences of vibration. Therefore this study decided to improve pile foundation of bridge or viaduct by setting shock absorber on the pile.To find out a better effect of vibration reduction with the proper condition of dynamic displacement limited by designing code, this study filled air in the shock absorber. By changing the air volume in the shock absorber to perform a series of experiments.A trend between effect of vibration reduction and volume ratio of filled air was obtained from the results of experiments. Larger volume ratio of filled air may result in better effect of vibration reduction, and the maximum dynamic displacement has the same tendency. Beyond 10% of the volume ratio of filled air, the maximum dynamic displacement increased rapidly with the increasing of filled air, while the vibration reduction effects do not have apparent increasing rate. Furthermore, within the range of 10%~40% of volume ratio of filled air, the vibration reduction effects and maximum dynamic displacement increased rapidly with the increasing of filled air. In the range of volume ratio of filled air lager than 40%, the increasing rates of vibration reduction effects and maximum dynamic displacement are small.