MEASUREMENT OF THE NATURAL FREQUENCY AND DEFLECTION OF THE WIDESPAN-FLOOR SYSTEM DUE TO DYNAMIC LIVE LOAD

Abstract

Study on the natural frequency of a floor-structural system is a key parameter to determine
how the floor system will respond to forces causing vibrations. Measurement of frequency and displacement
of the floor system was the focus of this research. The main objective of this investigation is to develop a
boundary of the natural frequency of the floor system for the widespan building. The observation was
conducted for two different human activity that is walking (during graduation ceremony) and dancing (during
live music). The results of the study shows that the frequency of floor system due to human walking activity
was measured between 3.54 to 5.32, while, rhythmic dance and jumping activity yields the frequency
between 4.17 to 5.08 Hz. At the range of the measured frequency, the human walking induced maximum
deflection of the floor about 1.76 to 7.81 mm. The deflection is double about 15.36 to 33.18 mm when 30 to
35 peoples were dancing/jumping in unison in response to live music.