The Seismic Provisions in RISA-3D will check various design and code check requirements according to the AISC design provisions (AISC 360-2005, AISC 341-2005, AISC 358-2009). Seismic Design Rules can be applied to any member in the model, just follow the steps listed below.
The Seismic Design rules can be found in RISA-3D on the Data Entry toolbar or in the Spreadsheets menu. Below is a quick-reference description of the entries required. For further information refer to the Online Help File > Seismic Detailing.
When a model is solved that contains Member Area Loads, the program automatically attributes them to the applicable members within the defined area of the applied load. The load is attributed to the members as distributed loads that RISA-3D defines as Transient Loads.
When your RISA-3D model is not behaving as you anticipated, one of the best tools you have is viewing the deflected shape. Displaying the deflection graphically will help you visualize how the model is behaving and will often times bring to light modeling errors.
RISA-3D now has the ability to define the seismic parameters Rho, Omega and SDS directly into load combinations. If you open the Basic Load Cases spreadsheet and click into the BLC column, the dialog offers the ability to add these values in to factor the load.
Applying seismic loads to structures with rigid diaphragms can be done automatically in RISA-3D. In the image below we have a structure that has rigid diaphragms and the seismic load has already been applied at each diaphragm level.
In RISA-3D, there are numerous options for Member End Releases which should not be confused with Boundary Conditions.
Before reading this, be sure to check out the article linked below on X-Bracing. In RISA-3D, you can set a member to be tension-only by selecting it and selecting Tension Only or Euler Buckling from the Additional Properties section of the Member Properties.
There are several tips to modeling X-Bracing within RISA-3D that can help the model solve faster and give you better results.
