Model: Dynamic Curve Function

 

 

 

 

Function

Enters the time history load for the seismic analysis of the ground

 

 

 

 

Call

1D Equivalent Linear Analysis Module : Model > Ground Acceleration

 

 

 

 

 

<Dynamic Curve Function>

 

Add Accel.

Enter the new acceleration data

 

Modify/Show

Check and modify the inputted data

 

Delete

Delete the inputted data

 

 

 

Export

       Export the ground acceleration function to 'txt' format. The data of FFT(Fast Fourier transform) also can be checked with 'txt' format.

 

Function Name

Select the time history analysis conditions inputted in the function.  

Click the button to call the function if it has not been inputted already
 

Time Forcing Data Type

Normalized Accel.

The acceleration spectrum has been divided by the gravity acceleration, thus it cannot be set to other types

 

Scaling

Enter the scale factor of the Ground Acceleration Function

Scale Factor

Enter the scale factor

 

Maximum Value

Modify the spectrum data so that the maximum acceleration fits the value desired by the user
 

Gravity

Enter the gravity acceleration
 

Graph Options

Assign whether or not the Graph will be displayed as a log Scale by axis-direction

 

Description

 

Enter a brief description that explains the Ground Acceleration Function.  When the default values for seismic waves generation is used for generation, the applied maximum acceleration and period are displayed.   

 

In FFA, for the user's convenience, the following 3 time history load entry methods are provided.  For the seismic load input, the value for the time history acceleration divided by gravity acceleration is supported only.  

  1. Saving the file and retrieving the frequently used time history load

  2. Accessing the time history load data stored in the database

  3. The user directly entering the data

1. Saving the file and retrieving the frequently used time history load

: This is used when a time history load is inputted from a data created, and the data creates the file extension as ".sgs" or ".thd" format as described below.

'fn.sgs' File Format

*SGSw

A proclamation stating that this file is a "Seismic Data Generator" (seismic data auto extraction module) data format of MIDAS/Civil

*TITLE, Elcentro 1940, N-S Component

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*X-AXIS, Second

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*Y-AXIS, Normalized Acceleration

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*UNIT&TYPE, GRAV, ACCEL

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*FLAGS, 0, 0

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*DATA

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1.00000E-010, 3.50102E-001

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5.00000E-002, 3.82861E-001

 -

1.00000E-001, 5.08226E-001

 -

1.50000E-001, 5.17459E-001

-

:

-

 

'fn.thd' File Format - Input by user

Optional

** Comments - Entry allowed anywhere

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*UNIT, M , N - length : MM, CM, M, INCH, FEET, GRAV possible

 

*Load : KG, TON, KN, LBF, KIP

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*TYPE,  ACCEL - ACCEL, FORCE, MOMENT possible

Required

*Data

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X1 , Y1 (X : Time, Y : Time Function)

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X2 , Y2

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X3 , Y3

-

:

 

 

2. Accessing the time history load data stored in the MIDAS/Civil database

 : A function creating the time history load by retrieving various seismic data from the database.  A total of 32 different seismic accelerations are stored in the database.

 

<Earthquake>

 

3. Directly entering data in the Add/Modify/Ground Acceleration Functions dialog box

The time history load can be formulated by directly entering the time history load values in the fields on the left of the dialog box.