SAP2000 Nonlinear Dynamic Analysis

Workshop Nonlinear Dynamic Analysis in SAP2000 Manish Kumar Post-doctoral Associate Civil, Structural and Envir Environmental onmental Engineering University at Buffalo, State University of New York (SUNY)

EERI Engineering Workshop

1/12

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Outline •

Nonlinearity

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Modal analysis

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Pushover analysis

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Response spectrum analysis

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Response history analysis







Geometric nonlinearity







Geometric nonlinearity •

P-Delta –

–

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Geometric stiffness matrix formulated at beginning

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P-Delta + large deformations –

Computational efficient efficient

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Appropriate when vertical loads do not vary

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Stiffness matrix updated at each step Computationally expensive Appropriate when







Geometric nonlinearity •

Two ways to include P-Delta effects –

Create static static nonlinear case for each load combination •

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Only for static analysis

Create initial P-Delta for anticipated gravity loads •

Use modified stiffness from this for all analysis







Material Mat erial nonlinearity •

Concentrated yield –

Appropriate for frame members

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Assign at the member ends

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Discretize Discretize members using “hinge overwrites to get better convergence









Modal analysis •

Eigen vectors

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Ritz vectors







Pushover analysis Create the computational model

• Creat Createe SAP2 SAP2000 000 mode modell • Define hinge hinge properties properties and assign assign it to frame frame elements elements • Define load pattern pattern applied during pushover analysis analysis







Time-history Time-history analysis •

Modal –

Linear & nonlinear

Modal nonlinear

•

Direct integration –

Linear & nonlinear Appropriate to capture







Time-history Time-history analysis •

Modal –

Linear & nonlinear

Modal nonlinear

•

Direct integration –

Linear & nonlinear Appropriate to capture







Local axis •

Local axis 1 is always the longitudinal axis

•

The default orientation of the local 2 and









SAP2000 Nonlinear Dynamic Analysis

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