The ceremony took place in front of a monument for the victims of the tragic accident at the northern end of the bridge that crosses the Han River.
A total of 32 people, including girl students, were killed and 17 others injured when a middle section of the bridge fell into the Han River during the morning commuting hours on Oct. 21, 1994.
The bridge, which links Seongsu-dong in northern Seoul and Apgujeong-dong, southern Seoul, was rebuilt and re-opened in 1997.