Ponding stability on space truss roof system

Ponding stability which subject is inserted into the code of steel structure design and construction drafted in our country in these days, is main concern of this study. In Chapter 3.4 at Ponding Stability topic, literature review is done about the accumulation of water in the roof system to have sufficient strength and rigidity against the action to the requirements. In 1962, Haussler is the first man who come up with the ponding stability idea. After his calculations, resarchers continue their studies up to present and some changes observed like changes in assumptions and changes in empirical formulas. In Chapter 3, causes and prevention methods of ponding is handled, too. The requirements of the roof drainage system to prevent ponding effect is identified in codes. According to the codes, there should be two system to work controlled. One is siphonic system located on the roof, the other is scuppers located at the level of roof membrane on the parapet wall. It means, in case of siphonic system failed, scuppers work properly. Height of the parapet wall that is concern for the architects can not be ignored since it has importance for the working principle of scuppers. In Chapter 5, to see how ponding triggers the roof members to loose their stiffness and strength, numerical analysis is done on the steel roof which is nearly flat. The alternate method is used for both linear and nonlinear static anaylsis.