G.18.104.22.168 Scope of Pushover Analysis in STAAD.Pro
Pushover Analysis in STAAD.Pro will produce valid results only when following conditions are satisfied:
- Buildings are regular and do not have adverse torsional or multimode effects. The capacity curve is generally constructed to represent the first mode response of the structure based on the assumption that the fundamental mode of vibration is the predominant response of the structure.
- Fully rigid moment frame and concentric braced frame are considered. If any member release is defined, its effect will be same as that for linear analysis.
- Only steel structures are considered (i.e., material cannot be concrete).
- Only straight beam and column members are considered (i.e., no curved members, no plate or surface elements).
- All members of a structure are considered as primary element. No secondary elements are considered.
- For built-in FEMA hinge formation, out of six degrees of freedom, hinge formation is considered for bending moment about local z axis of beam. For column, hinge formation is considered for bending moment about local z axis of column or for bending moment about local y axis of column, whichever moment becomes the guiding factor. Depending upon the guiding criteria given in FEMA 356:2000, hinge formation in beam is deformation-controlled and that in column can be deformation-controlled or force-controlled. For braced (i.e. truss) member, axial hinge is considered. Beside moment and axial hinge, no other types of hinge formation (e.g. hinge formation due to shear or hinge formation due to coupled effect of axial force and bi-axial bending moment) are considered.
- Built-in hinge properties and acceptance criteria for beam and columns given in Tables 5-6 and 5-7 of FEMA 356:2000 for beams, columns, and braces are considered.
- User defined hinge properties are considered for beam and column for hinge formation for bending moment only. For column, only deformation-controlled action is considered as no axial force is considered for checking force-controlled action in column.
- Out of five methods for lateral load distribution, three methods have been implemented as per Section 22.214.171.124.3 of FEMA 356:2000. The methods implemented are 1.1, 1.2, and 2.1 of Section 126.96.36.199.3 (See G.188.8.131.52 Lateral Load Distribution).
- Performance point of a structure is calculated based on Displacement Coefficient method to find target displacement.