Spectrum Parameters dialog
Used to generate a response spectrum curve per generates the spectrum based on the inputted data and as per section 11.4.5 of the ASCE-7-05 code (which is referenced by the International Building Code).
Opens when the Generate Spectrum button is clicked in the Create New Load Item dialog from the Response Spectra tab (with Custom selected for the code).
| Setting | Description |
|---|---|
| Select Zip | Type or select the Zip code (US Postal code) to look up the geographic location. |
| Find Lat/Long | Click to update the Latitude and Longitude values if the postal code value changes. |
| Latitude / Longitude | Type the geographic coordinates of the site here, if know. These fields will be populated if the Select Zip or Find Lat/Long options are used. |
| Calculate S1 / SS | Click this button to recalculated the seismic acceleration coefficients if the Latitude and/or Longitude values were manually entered. |
| S1 | This is the mapped MCE spectral response acceleration at a period of 1 second, determined in accordance with section 11.4.1 of ASCE-7-05. It is calculated by setting the Zip code or by clicking the Calculate S1/SS button. Alternatively, you may specify this value directly. |
| SS | This is the mapped MCE spectral response acceleration at short period, determined in accordance with section 11.4.1 of ASCE-7-05. It is calculated by setting the Zip code or by clicking the Calculate S1/SS button. Alternatively, you may specify this value directly. |
| Site Class | This is the classification (A to F) assigned to a site based on the soil type as defined in chapter 20 of ASCE-7-05. Values of Fa and Fv from the IBC table are displayed for reference. If the classification is set to F, then you must specify the parameters Fa and Fv. |
| Fa | Short period site coefficient determined in accordance with table 11.4 -1 of ASCE-7-05. This is determined by the Site Class, but must be specified if the Site Class is set to F. |
| Fv | Long period (1 sec) site coefficient determined in accordance with table 11.4 -2 of ASCE-7-05. This is determined by the Site Class, but must specified if the Site Class is set to F. |
| Start / End | Specify the start and end times (T) to define the response time range. |
| Interval | Specify a time step interval for generating the curve. |
| Generate Spectrum | Closes the dialog and generates response spectrum curve data. The Generated Spectrum dialog opens to review the IBC response spectrum data. |
| Cancel | Closes the dialog without generating response spectrum data. |