The floor vibration which character was overwhelming might interrupt the
convenience of the building users due to the the human activity, it can be
controlled by increasing the floor stiffness. One of the ways to increase the floor
stiffness was using the stiffeners (queen post hanger) that should be installed
under the plate of the floor.
According to ISO 2361-1/2 the criteria of limits for the floor natural
frequency was 4-8 Hz. Above the limit, people would experience higher vibration
acceleration, the statement implied that if the building users would like to be more
convenient with the floor vibration, then the floor natural frequency should be in
the limit that had been determined.
There were two ways for predicting the floor natural frequency namely by
means of design guideline that had been developed by Murray et al. (1997) and by
means of time history analysis by using ETABS. An appropriate approach for
predicting the size of the floor natural frequency had been developed and one of
the ways was the method of beam equivalent for composite floor.
The results of analysis showed that the floor natural frequency without the
stiffeners was 0.45 Hz with the design guideline; on the other hand, the floor
natural frequency as measured by means of ETABS was 0.49 Hz. As a result, the
floor natural frequency was above the limit that had been determined. For the
floor that had been installed with the stiffeners, the floor frequency was 5.56 Hz
by means of design guideline and was 5.26 by means of ETABS. Due to the
dynamic load that was taken from the heel impact, the displacement of vertical
maximum direction occured in the middle of the floor extend namely 1.18 cm
before the stiffeners was installed and was 0.36 cm after the stiffeners was
installed. The stiffeners that the research installed was quite ideal for decreasing
the vibration occured in the floor.