Response Spectrum Functions |
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Enter spectral data for response spectrum analysis. Response Spectrum Analysis calculates modal responses using the natural periods obtained by Eigenvalue analysis. Therefore, Response Spectrum Function must be defined, which includes the range of the considered natural periods obtained from the Eigenvalue analysis. Range of the natural periods obtained from Eigenvalue analysis
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From the Main Menu. select Load > Seismic > Response Spectrum Functions. |
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Enter new or additional spectral data Click . Modify previously entered spectral data Select the relevant spectral data from the spectral data list of the dialog box and click . When deleting previously entered spectral data Select the relevant spectral data from the spectral data list of the dialog box and click . Click or to display the dialog box below and enter the required data in the relevant entry fields. Function NameEnter the name of the spectral data. The name is used in "Response Spectrum Load Cases" which is the function used to enter response spectrum load cases. Spectral Data TypeAssign the spectral data type to be entered. Normalized Accel. : Spectrum obtained by dividing the acceleration spectrum by the acceleration of gravity Acceleration : Acceleration spectrum Velocity : Velocity spectrum Displacement : Displacement spectrum Note ScalingScale Factor: Specify a multiplier for Response Spectrum Data. Maximum Value: Maximum value of Response Spectrum Data can be controlled by the user. Scale FactorSpecify a multiplier for Response Spectrum Data. Maximum Value Maximum value of Response Spectrum Data can be controlled by the user. GravityEnter the acceleration of gravity. Damping Ratio Specify a Damping Ratio applicable to the response spectrum, which will be used in response spectrum analysis. Graph OptionsSpecify whether or not to produce Graph in Log Scale. DescriptionEnter a brief description of Response Spectrum Data. When the Design Spectrum has been generated, the basic Spectrum Data such as soil & area coefficients and importance & response factors are displayed. For convenience, midas Civil supports the following 4 entry methods:
Create files containing frequently used response spectrum load cases, then retrieve the files
'fn.sgs' file format
'fn.spd' file format - User-defined
'fn.thd' file format - User-defined ** Comments - Entry allowed anywhere
Access the built-in response spectrum load cases in midas Civil database
The built-in design spectrum types are as follows : IBC2000(ASCE7-98): International Building Code 2000 UBC (1997): UBC 97 standards UBC 88-94: UBC 91 standards NBC (1995): National Building Code of Canada 1995 Eurocode-8 (2003): Design provisions for earthquake resistance of structures. General rules. Strengthening and repair of buildings. Eurocode-8 (1996) Design: Design provisions for earthquake resistance of structures. General rules. Strengthening and repair of buildings. Eurocode-8 (1996) Elastic: Design provisions for earthquake resistance of structures. General rules. Strengthening and repair of buildings. IS1893 (2002): Indian Standards TaiwanBrg (89) Horizontal: Taiwan Seismic Code TaiwanBrg (89) Vertical: Taiwan Seismic Code China (GS50011-2001): For Chinese version Note China (JTJ004-89): For Chinese version Note China (GBJ111-87): For Chinese version Note China Shanghai (DGJ08-9-2003): Shanghai Code for Seismic Design of Buildings Japan (Arch, 2000): For Japanese version Japan (Bridge2002) Korea (Bridge): Specification for Roadway Bridge Korea (Arch, 2000): Buildings loading criteria and commentaries Korea (Arch, 1992): Regulations related to structural criteria for buildings Note Importance factor (I) in the combo box can be defined by selecting the factor in the drop-down menu or by typing the factor directly.
Enter directly the spectral data in the entry fields in the Add/Modify/Show Response Spectrum Functions dialog box The user directly enters the period and spectrum values in the entry field to the left of the dialog box. For easy interpretation, the spectrum functions are processed in graphs representing spectrum values vs periods. The spectrum functions corresponding to the natural periods of the structure are linearly interpolated in the response spectrum analysis. Thus, it may be prudent to provide functional values at closed intervals where the curvature suddenly varies. In addition, the range of periods for the spectrum functions must include all the natural periods of the structure. |
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