Abstract
The bridge pylon has a slender structure, so it is very sensitive to the effects of dynamic loading, such as wind or earthquakes. One of the types of devices used to reduce vibrations of bridge pylons is the tuned liquid damper (TLD). This device has been used for Bai Chay bridge pylon in Vietnam. This paper presents the calculation of free vibration of a bridge pylon installed with TLDs at the top of the pylon. The calculation results of free vibration as natural frequencies and mode shapes will be the fundamental for solution of forced vibration of the bridge pylon under the effects of dynamic loading.