For building structural systems, 3D analysis model is created automatically.
The stiffness of cracked sections are generated automaticaly.
The stiffness and strength of elements which are important to distribution of deformations and forces are included in analysis.
The model includes ‘stiffness properties of cracked concrete sections’ and the contribution of panel zone deformations for steel moment frames.
For building structural systems, 3D analysis model is created automatically. Structures that have horizontal structural irregularity Type 1a, 1b, 4, or 5 of Table 12.3-1 must be analyzed using a 3D representation. A minimum of three degrees of freedom consisting of translation in two orthogonal plan directions and rotation about the vertical axis are included and the designer can interfere the freedoms from structural tree - modal analysis case - dynamic degrees of freedom.
If the diaphragms have been classified as semi-rigid, the model includes representation of the diaphragm’s stiffness characteristics and, diaphragm’s degrees of freedom and stifness are included dynamic analysis.