Hinge Property [STG]
Hinges represent points in the structural model where plastic deformation is expected to occur under seismic loads. They are essential for nonlinear pushover analysis to capture the inelastic behavior of pier columns. It can be assigned to columns as shown below, at both the top and bottom locations.
Nonlinear
Hinge Stiffness Option [From Report/User Input]: The user can define how the hinge stiffness is determined:
From Report: The hinge stiffness is automatically derived from the Moment-Curvature Report.
User Input: The user directly specifies hinge stiffness values for each axial force.
Moment Curvature Report: If “From Report” is selected, the Moment Curvature Report should be directly assigned using the From Report column to extract hinge stiffness parameters.
Hinge Stiffness: If the user selects the option ‘Set to User Input’ in the ‘Hinge Stiffness Option’ column, further definitions can be made using the ‘Hinge Stiffness’ column's ‘Edit…’ option, detailed by Axial Force/Fixity (Ry)/Fixity (Rz). When defining hinge stiffness data, make sure to include a sufficient number of axial force data points around the expected dead load level.
Define hinge stiffness data with enough axial force points around the expected dead load for stable nonlinear convergence.
Use intervals of about 50 kips near the maximum load.
Example: For a –750 kip dead load, enter values such as 250, 0, –50, –100, … –1000 kips.
Positive values indicate tension, and negative values indicate compression - both are required for accurate nonlinear analysis.
Linear
Transition along the axes (Tx, Ty, Tz) and rotation (Rx) can be determined for hinges. The definitions can be made either by numbers or by the option ‘Fixed'.
Tx[Fixed/Stiffness]: Transition along X-axis.
Ty[Fixed/Stiffness]: Transition along Y-axis.
Tz[Fixed/Stiffness]: Transition along Z-axis.
Rx[Fixed/Stiffness]: Rotation along X-axis.
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