etabs_set_is1893_seismic_params
Compute IS 1893 seismic scale factors for response spectrum analysis. Calculates scale factor from zone, importance, reduction, soil, damping, and returns results with clause references.
Instructions
Compute and report IS 1893:2016 seismic scale factors for RSA cases.
Calculates the scale factor SF = (Z/2) × (I/R) × (g/Sa_g_at_T1) for use in etabs_define_response_spectrum.
The full equivalent static base shear: VB = Ah × W where Ah = (Z/2) × (Sa/g) × (I/R)
For response spectrum analysis the ETABS scale factor applied to the spectrum function is typically: g × I / R (when the spectrum function is already in units of Sa/g, i.e. normalized). ETABS multiplies the function value by scale_factor to get spectral acceleration in length/time² units.
Args: load_case_x: Name of RSA case in X direction (e.g. "EQX"). load_case_y: Name of RSA case in Y direction (e.g. "EQY"). zone: IS 1893 seismic zone "II", "III", "IV", or "V". importance_factor: I — importance factor (1.0 ordinary, 1.2 important, 1.5 critical). IS 1893:2016 Table 8. response_reduction: R — response reduction factor. IS 1893:2016 Table 9. Typical: OMRF=3.0, SMRF=5.0. soil_type: Site type "I" (hard), "II" (medium), "III" (soft). IS 1893:2016 Table 1. damping_ratio: Critical damping ratio (default 0.05 = 5%). IS 1893:2016 Cl. 6.4.6. structure_type: "RC_frame", "Steel_frame", "Shear_wall", "Composite". Used for informational note only. modal_case: Name of the modal case. apply_scale_to_rsa: If True, returns ready-to-use ETABS scale factor (in m/s² for SI kN_m models). Set False for kip_ft models.
Returns: JSON with zone factor Z, Ah, scale factors, and IS 1893 clause references.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| load_case_x | Yes | ||
| load_case_y | Yes | ||
| zone | No | III | |
| importance_factor | No | ||
| response_reduction | No | ||
| soil_type | No | II | |
| damping_ratio | No | ||
| structure_type | No | RC_frame | |
| modal_case | No | MODAL | |
| apply_scale_to_rsa | No |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |