The aim of this paper is to present a practical yet simplified method in the second-order analysis of semirigid connected steel frames. Based on the principle of new shear force distribution method, by taking partial frame as an analytical subassembly model and using a rotation spring which has variable bending stiffness to model flexibility of beam-column connection, this paper derives a simplified non-iterative inner force and lateral deflection computation formula considering P-Delta effects on semirigid connected steel frames. The numerical examples show that semirigid of beam-column connections obviously increases the horizontal displacement and P-Delta effect on the steel frame. Therefore the influences of semirigid connection should been considered in second-order analysis of building steel frame. The presented method is not only relatively practical and easily applicable to manual computation but also has a rather high accuracy, and can be used by the engineers in preliminary design for semirigid connected steel frames.
New stability design of steel frames with stepped cross sections by the elastic second-order analysis.
