Create: Response Spectrum Definition dialog
This dialog is used to add code-prescribed parameters for a response spectra analysis to the structure. A response sprectrum is used to model dynamic seismic loading of a structure.
In this dialog, there are some instances where a code or parameter selection will result in a control being disabled. In the case where there is not selection to be made or a value to be fixed (as the code only allows for one option), then that selection or value will be displayed but cannot be edited.
EN 1998 - 2004 Parameters
|Design Ground Acc||The "Ground Acceleration On Type A Ground" and defined in Eurocode 8 as ag, as used in equations 3.2 – 3.5. Refer to the Eurocode for further information.|
|Behavior factor||An approximation of the ratio of the seismic forces that the structure would experience if its response was completely elastic with 5% viscous damping, to the seismic forces that may be used in design, with a conventional elastic analysis model, still ensuring a satisfactory response of the structure.|
|Subsoil Class||This parameter is used to define
the subsoil conditions based on which the response spectra will be generated as
defined in Table 3.1 Ground Types. Based on the subsoil conditions the soil
types may be of five kinds:
Please refer section 3.2 of Eurocode 8 for detailed guidelines regarding the choice of soil type.
|Load Type||The response spectrum loading can be based on either Elastic or Design response spectra. Refer to Eurocode 8.
The capacity of structural systems to resist seismic actions in the nonlinear range generally permits their design for forces smaller than those corresponding to a linear elastic response. To avoid explicit nonlinear structural analysis in design, the energy dissipation capacity of the structure through mainly ductile behavior of its elements and/or other mechanisms, is taken into account by performing a linear analysis based on a response spectrum which is a reduced form of the corresponding elastic response spectrum. This reduction is accomplished by introducing the behavior factor Q and the reduced response spectrum is termed as "Design Response Spectrum." STAAD.Pro generates the Elastic Response Spectra using the guidelines of section 4.2.4 and Table 4.2 of Eurocode 8.
So, if the structure is supposed to resist seismic actions in the nonlinear range the Design Response Spectra is to be used.
|Type||Two types of response spectra curve can be generated based on either response spectra type 1 curve or response spectra type 2 curve.|
IS 1893 - 2016 Parameters
|Subsoil Class||Select the subsoil classification or to provide
Custom values. Depending upon time period, types
of soil and damping, the average response acceleration coefficient, Sa/g is calculated.
If Custom is selected, provide the data pair Values.
SP14.13330 - 2011 Parameters
|Zoning Factor||The zoning factor based on maximum acceleration factor for the seismic zone. This factor must be modified for Subsoil Class selections other than 2.|
|Subsoil Class||Defines the subsoil conditions on which the response spectrum will be generated.|
IBC 2015 / ASCE 7 2010
|Long Period (TL)||Long-Period transition period in seconds. (IBC 2015, ASCE 7-10 Chapter 22)|
|Fa||Optional Short-Period site coefficient at 0.2s. Value must be provided if SCLASS set to F (i.e., 6). (IBC 2006, ASCE 7-05 Section 11.4.3)|
|Fv||Optional Long-Period site coefficient at 1.0s. Value must be provided if SCLASS set to F (i.e., 6). (IBC 2006, ASCE 7-05 Section 11.4.3)|
|Site Class (SCL)||Select A through F for the Site Class as defined in the IBC code. (IBC 2000, Section 1615.1.1 page 350. IBC 2003, Section 1615.1.1 page 322. IBC 2006 ASCE 7-05 Section 20.3)|