Dynamic Instability of Light-weight Steel Structures with Portal Frames Under Wind and Snow Loads

Abstract:

The dynamic instability of light-weight steel structures with portal frames under coupled wind and snow loads is studied by numerical simulation and wind tunnel tests.Coupled action between wind and snow is simulated by computational fluid dynamics(CFD)method and the unsteady aerodynamic forces on the structure are obtained by wind tunnel test.Then,the structure is studied as a spatial portal frame on its dynamic instability by the Budiansky-Roth criterion.The results show that simulated snow-drifting on the roof is consistent with the movement rule of airflow near the roof.Non-uniform snow distribution can decrease the dynamic stability of the structure simultaneously under wind actions.

Key words:wind and snow loads; portal frames; light-weight steel structures; dynamic instability; computational fluid dynamics(CFD); wind tunnel tests