Computer Programme for the Dynamic Analysis of Tall Regular Frames
The traditional method of dynamic analysis of tall rigid frames assumes the shear frame model. Models that allow joint rotations with/without the inclusion of the column axial loads give improved results but pose much more computational difficulty. In this work a computer program Natfrequency that determines the dynamic stiffness matrix of tall frames and solves the eigenvalue problem when modeled as a shear frame and when joint rotations with/without the inclusion of the column axial loads was developed.
Results obtained using Natfrequency were in total agreement with those obtained manually and were obtained in seconds. It is recommended that with tall buildings becoming less stiff and more susceptible to dynamic disturbances, that models, which allow joint rotations with/without the inclusion of the columns' axial loads, be used for their analysis.