The matrix analysis of nonorthogonal frames

Abstract

The purpose of this thesis is to investigate the characteristics of the forces and displacements associated with the statical stiffness matrix analysis of orthogonal and nonorthogonal portal frames. The frames are subject ot the effects of axial force as well as transverse static forces.

A variety of problems are analyzed using matrix analysis techniques. Problems of orthogonal frames with different transverse load conditions, including or excluding axial force are considered initially for analytical purposes. Next, problems of nonorthogonal frames with different loading conditions, both axial and transverse, are considered. The effect of member slope on the matrix analysis techniques is investigated and calculated.

Finally, a symmetric nonorthogonal frame with both members inclined is considered using an approximate method as well as exact method. The nonlinear load-deflection characteristics of the frame are determined.

In general, it is found that the inclusion of axial stiffness for orthogonal frames is not necessary for solving the analytical problem. It must, however, be presented int he stiffness matrix definition for nonorthogonal frames if reasonable numerical results are desired.