Navigation:  Calculation Modules > Loads & Forces Divisions > ASCE 7-22 Seismic Base Shear

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This module is a presentation of equivalent lateral force procedure seismic provisions in ASCE 7-22.

 

All of the references to ASCE 7 are given on the module screens. Above each screen capture are notes as needed to call attention to entries or explain usage.  

 

The module is designed to allow you to work downwards through the tabs on the left side of the screen. ASCE 7 skips all around in its definitions of things to check. This module simplifies the process by properly ordering the items and the necessary decisions to be made in working toward a final seismic base shear value.

 

The program includes a link to the USGS databases of seismic ground motion specifically for use with ASCE 7-22.

 

General

 

 

Ground Motion

 

 

 

Site Class, Site Coefficients and Seismic Design Category

Select the appropriate Site Class based on the geotechnical conditions.

 

 

Selection of Seismic Force Resisting System

Click one of the large boxes at the top of the tab to load the table with specific selections for that general category of Seismic Force Resisting System.

 

Note the checkbox for systems with flexible diaphragms. This may not apply to some building systems...check ASCE for details on the particular system of interest.

 

 

Redundancy Factor

Depending on the Seismic Design Category determined from the prior selections of Occupancy, Seismic Ground Motion and Building System, the Redundancy Factor per ASCE will be shown here.

 

 

Specification of Building Period

All four ASCE 7 options for building period determination are available here.

 

 

 

Long-Period Transition Period Reference Maps

Maps copyright ASCE.

 

 

Cs: Seismic Response Coefficient

Please check ASCE 7 section references for details.

 

 

Vertical Distribution of Base Shear

This tab calculates the vertical distribution of seismic forces.  Use the [Add] button for each new level. To edit information for a level, highlight the corresponding line and click [Edit].

 

 

Diaphragm Forces

Using the information entered above (on the prior tab) the force distribution results are shown here.