STAAD.Pro offers several analysis methods as noted below:
• Perform Analysis – instructs STAAD to perform a linear elastic (stiffness) analysis.
• P-Delta Analysis – performs a second-order elastic analysis that considers the effects of the applied loads acting on the displaced structure (P-Δ effect). This type of analysis is generally preferred by most building codes. This is an iterative analysis process. This analysis type also has options to specify the number of iterations to be performed or to place a convergence tolerance on the displacements from successive iterations. There is also an option to include the P-δ (small delta) effect, which considers the effect of applied loads acting on the deformed shape of individual members. Finally, this analysis includes an option to include the Geometric Stiffness (Kg) matrix, which modifies the member stiffnesses based on the applied loads.
• Cable Analysis – performs a non-linear cable analysis on a structure that contains non-linear cable members
• Direct Analysis – performs a Direct Analysis. This method accounts for the second-order effects resulting from deformation in the structure due to applied loading, imperfections, and reduced bending stiffness of members due to the presence of axial loads. This analysis is similar to a P-Delta Analysis with the Use Geometric Stiffness (Kg) and Small Delta options selected. However, this analysis calculates modifications to the stiffness matrix using the τb factors described in AISC 360-05.
• Generate Floor Spectrum – used to request the calculation of floor and/or joint response spectra from time history results. This is particularly useful in the analysis of floor systems supporting vibrating equipment. This feature requires a license for the Advanced Analysis Engine.
• Imperfection Analysis – considers the secondary effects of loads acting on members that have an initial curvature (camber) or an initial drift This analysis is used on structures that have members with an Imperfection specification applied to them.
• Buckling Analysis – identifies the factor by which the loads in the selected load case should be increased (or decreased if the factor is less than 1) such that Euler buckling first occurs in any member of the structure.
• Pushover Analysis – performs a static, non-linear procedure in accordance with FEMA 356. In this method, a lateral “push” load is applied to the structure and increased progressively according to a predefined loading pattern until either the loading or the structure displacement reaches a prescribed level. This method considers the non-linear behavior of the structure, allowing plastic hinges to form in the structure until a collapse mechanism is created. This technique is typically applied for the seismic rehabilitation of structures.