Intro
This plugin automatically converts the direction of inertial forces acting on the piers of a curved bridge.
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When applying inertial forces to curved bridges, you do not need to manually calculate and input load directions for each pier.
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The plugin transforms and applies the horizontal inertial force to the closest orientation of each pier, aligned with the global coordinate system or user-defined angles.
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This is particularly useful for modeling complex bridge geometries, where the piers and global coordinate system do not align, streamlining seismic analysis workflows.
Version
- v1.0.0 : Release
Applicable standards
- General Use
Benefits of this plugin
To apply inertial forces to curved bridge piers in MIDAS CIVIL, users traditionally calculate and input load directions for each pier manually, which is time-consuming and prone to errors. This plugin allows users to input a single rotation angle or multiple angles for inertial forces and generates the corresponding load cases automatically. It simplifies the process, saving time and ensuring accuracy without the need for manual transformations or repetitive input.
How to use this plugin?
[Inertial Force Controller - Load Case Setting]
- Select the Time History Load Cases Name
In these lists, time history load cases for products with the Analysis Method set to "Static" type are displayed. - Select the Static Load
The static loads as shown are limited to cases where "Nodal Body Force" and "Nodal Loads" are assigned. - Select the time History Functions Select the time History Functions
The time history functions with the "Normal" type for the Time Forcing Functions Data configured in the product settings are displayed.Additionally, it provides the following "Linear" function as default (Preset: Linear).
[Inertial Force Controller - Scale Factor/Angle Setting]
- After inputting the load case information, input the scaling factor(4) for the time load function and the angle of the horizontal load(6). This angle represents the rotation of the X-axis concerning the Z-axis of the global coordinate system, which is aligned with the direction of the horizontal component of ground acceleration. You can input a positive real number, and using the "+" button(5), users can define multiple rotation angles.
- *Be careful: (4)The scale factor should be larger than zero. and (6) angles cannot be defined as the same size.
- After inputting previous information, press the Create button(7). Then, MIDAS CIVIL NX will newly create static load cases with added nodal body forces, time history load cases, time forcing functions, and time-varying static load as below.
The additional nodal body forces will be added in the form of "Static Load Name_angle deg" where the angle is in degrees, as configured in the "Static Load" setting.
- The existing input nodal body forces loads are transformed according to the following procedure based on the angle of the load.
Note
Coordinate-transformation Calculation
For example, when generated in the 30-degree direction, it automatically creates a static load case that is coordinate-transformed from the original static load.
Conclusion
The Inertial Forces Controller plugin automatically transforms the load direction of the inertia forces that need to be applied based on the number of braces, saving users time and eliminating potential human errors. Users only need to input the horizontal direction along the Z-axis of the global coordinate system to easily control inertia forces.