Effective length factor of a non-symmetrical cross-bracing system with a discontinuous diagonal

Abstract

A non-rectangular frame panel usually contains an asymmetrical cross-bracing system with interrupted diagonals, leading to a more complicated buckling behavior than a symmetrical bracing system with continuous diagonals. There have been many studies of the stability theory of symmetrical cross-bracing systems, but few related to non-symmetrical systems. In this study, we analyzed elastic out-of-plane buckling of a general non-symmetrical cross-bracing system with a discontinuous diagonal. The discontinuous and continuous diagonals have different material and geometrical properties, and are not intersected at their mid-spans. A characteristic equation is presented to compute the critical loading of a non-symmetrical cross-bracing system when the supporting diagonal is under either compression or tension. The results show that the characteristic equation of a non-symmetrical bracing system can be transformed into a form the same as that of a geometrically mono-symmetrical system. To facilitate design applications, direct closed-form empirical equations of effective length factor are established for a general non-symmetrical cross-bracing case. The validity of the proposed empirical equations was verified by comparing predicted and theoretical results, and those from a stiffness approach.