پايداري قاب هاي با مهاربندي دروازه يي با درنظر گرفتن امكان كمانش خارج از صفحه

OUT-OF-PLANE STABILITY OF GATE BRACING

In most residential buildings in Iran, using x and chevron type bracings might face some architectural obstacles due to the existence of doors and windows in the east-west direction of the structures. Gate bracing system is one of the options, which is considered by many structural engineers. This system is similar to chevron bracing, however, each chevron brace member is divided into two separate parts with different slopes and the separation joint is linked to the corner of the bay. Gate bracing is more efficient than the chevron bracing due to the provided architectural space, but has less lateral stiffness. Out-of-plane buckling in this system is a serious problem and its connections require special consideration. In this paper, the out-of-plane buckling of gate bracing system, with various geometries and connection details, has been investigated. Results indicate that in order to prevent the out-of-plane buckling of the bracing, the ratio of the out-of-plane to in plane cross sectional moments of inertia of the brace members should not be less than a certain amount, which depends on the geometry of the frame.