الفهرس | Only 14 pages are availabe for public view |
Abstract The current thesis aims to investigate the behavior of elevated water tanks under earthquake loads. Earthquake load can be considered as the most dangerous load effect on the water tanks. It causes sloshing of water in the tank. Sloshing can be defined as the movement of water with large displacements of an unrestricted free surface, which causes high loads on the tank walls. This leads to high compressive stresses on tank. Furthermore this load causes overturning moment at the tank base. In the current study, two steel elevated tanks are manufactured and tested to find their dynamic parameters (natural frequencies and mode shapes). The two tanks are studied in two cases. The first case represents the empty tank and the second case represents the tank that partially filled with water. The dynamic parameters of the two tanks are estimated by using the operational modal analysis. This method is new technique used in finding dynamic properties of the structures. In this method, only response of the tanks was measured by accelerometers. Impact hammer was used only to excite the tanks at their bases. Exciting force was not measured. A PULSE Multi-analyzer System was used to transform the responses of the tanks to laptop by relation between acceleration and time. Then MATLAP program was used to transform the response of the tanks from time domain decomposition to frequency. |