Seismic Load Pattern - User Defined Form

Use the  Seismic Load  Pattern - User Defined form to specify seismic coefficients for the load pattern  irrespective of any code, including the direction and eccentricity, story range, base shear and building height exponent. Use the Seismic Load Pattern form to specify loading using code compliant parameters.

• Direction and Eccentricity options. Choose to specify the X or Y direction of the seismic loading, or to specify the direction with a percentage of eccentricity that is applicable to all diaphragms. Use the Ecc Ratio (All Diaph) edit box to specify a value for eccentricity. Five percent is the default and is entered as 0.05. The eccentricity options have meaning only when diaphragms have been assigned to joint or shell object. The program ignores eccentricities where diaphragms are not present. See the Seismic Load Pattern form topic for more information about how eccentricities are applied when diaphragms are present in the model.

• Story Range options. Choose the Top Story and Bottom Story to specify the elevation range over which the automatic static lateral loads are to be calculated. By default the bottom story is the base of the building and the top story is the uppermost level of the building. See the Seismic Load Pattern form topic for more information about the relationship of story range to the specification of seismic loading.

• Factors options. Use these edit boxes to specify the Base Shear Coefficient and the Building Height Exponent, K.

See Also

Overwrite Eccentricities Form

Access the User Defined Seismic Loading form as follows:

1. Click the Define menu > Load Patterns command to access the Define Load Patterns form.

2. Type a unique name for the load pattern in the Load edit box, select Seismic from the Type drop-down list, and select User Coefficients from the Auto Lateral Load drop-down list.

3. Click the Add New Load button

4. Highlight the newly define load pattern in the display area and click the Modify Lateral Load button.

After a Quake load pattern has been defined as described above, highlighting the name of the previously defined pattern and clicking the Modify Lateral Load button will also display the form.