Abstract:
Steel structures have long been widely used in different countries because of their relative
economy and ease of construction. The connections of the constituent members of these
types of constructions play an important role in affecting the behavior of the structure. In
the conventional methods of steel frame analysis, the behavior of joints is represented by
idealized models, either as a rigid joint or a pinned joint. The available design techniques
are mostly based on these idealized conditions. In reality, most connections are semi-rigid
and possess certain amount of rotational stiffuess. They are termed as partially restrained
connections or semi-rigid connections. Experimental studies have shown that the
connection moment-rotation characteristics are non-linear and the analysis procedure
must follow non-linear approach.
A computet program capable of analyzing frames with semi-rigid connections has been
developed. The program is a non-linear type, iterative in nature and based on incremental
or stepwise loading. The program is a generalized one and can be used to analyze frames
with any type of known semi-rigid connections. The program can handle general types of
loading implementing through a series of load increments. The connection flexibility
effect has been incorporated by the matrix formulation given by Monforton and Wu. The
non-linear behavior of the connections has also been incorporated by the polynomial
moment-rotation relationship given by Frye and Morris polynomial model for different
types of connections.
With the help of the developed program several investigations have been performed to
study the behavior of steel frames with semi-rigid connections. The first study describes
the effect of flexible connections on the behavior of frames, its internal distribution 'of
forces and lateral drift. The effect of bracing, as a sway resisting system on high rise
building frames have also been studied. The effect of bracing on the internal force
distribution and in controlling the sway of frame has been studied. The behavior of frame
with mixed use of rigid and semi-rigid connections has also been encountered. Efforts
have been directed to find the best-suited orientation of mix-mode c~a steel
frame in this investigation. A comparison of the results as obtained by the non-linear
analysis of frame with those of linear analysis using single stiffness of connection has also been included in this work. Finally, the effect of connection size parameters of semirigid
connections on the behavior of frame has also been studied ..
