Q. What is Gust Response Factor?

For flexible structures such as a tall vertical process vessel, a Gust Response Factor, Gf is another essential variable needed to determine the wind forces involved.

Gust response factors Gf for main wind-force resisting systems of flexible buildings and other structures shall be calculated by a rational analysis that incorporates the dynamic properties of the main wind-force resisting system.

For flexible vertical vessels, defined as vessels with a fundamental (natural) frequency of vibration less than 1 Hertz [this includes vessels with an h/D ratio greater than 4 (h is defined as the total height of the vessel, and D is the vessel diameter measured to the mid-thickness of the vessel wall)], it is recommended that the value of Gf be determined, some other rational analysis method that incorporates the dynamic properties of the main wind-force resisting system.