When a model is loaded, it deflects. The deflections in the members of the model may induce secondary moments due to the fact that the ends of the member may no longer be vertical in the deflected position. These secondary effects for members can be accurately approximated through the use of...
Continuous tiedown systems are used to help resist overturning forces generated by lateral loads, and can be estimated in RISA-3D using the hold-down database and the strap forces.
When it comes to trusses in RISA-3D, boundary condition definitions (pin vs. roller) can make a huge difference. Let’s take an example of a typical roof truss. Note that a pin-pin boundary condition has been applied to the ends.
When using rigid diaphragm analysis in RISA-3D it can be useful to evaluate the story shear in each frame. This is a perfect application for the Internal Force Summation Tool. The first step is to solve the desired load combination.
RISA includes various advanced spreadsheet operations that make reviewing input and results easy.
RISA-3D automatically considers the complex wind combinations required by ASCE 7 using the wind load generator and the load combination generator.
When you model your building in RISAFloor, make sure that you define your slab edge as flexible. That will ensure that the entire contents of the diaphragm will use flexible behavior.
When dealing with a sloping site, it is often necessary to step-down the bases of columns and walls along the length of a building. The example below illustrates how to model this in RISAFloor.
RISAFloor is capable of automatically generating the wind loads on sloped roofs. Let’s look at an example of this with the model below:
