October 4, 2018

Drawing Grid and Other Modeling Improvements

RISAFloor v13 includes a variety of modeling features which allows users to quickly create and manipulate geometry. These features include construction lines, saved selections and copy elements from floor to floor. Overall, these features can be used to help engineers streamline their modeling workflow within RISAFloor.

Tags: RISAFloor ES, RISAFloor, New, Construction Lines, Modeling

September 6, 2018 | RISAFloor ES, RISAFloor, New, Modeling

Copy Elements from Floor to Floor

RISAFloor v13.0 now includes the added ability to graphically copy elements from one floor to another floor. This feature will expedite the modeling process by giving designers more control over which beams, columns, walls and joints are carried over to another floor. To access the tool, click on the Copy Selected Items button to open the dialog box. Once the dialogue appears, choose the Copy to Another Floor radio button. To graphically copy specific elements to another floor within RISAFloor, first select the elements that you would like to copy. In the below example, columns (3-E) and (4-E), beams M15, M16 and M17 and wall WP1 are selected to be copied to the floor above the current floor. Click the Copy Selected Items button, selecting the floor above the current floor (Floor Level 3), while also selecting which element types (beams, columns, wall and joints) you want to copy. Once the selection is made click Apply. The selected items will now appear on Floor Level 3…

September 9, 2015 | RISA-3D, RISAFloor, New, Analysis

Why don’t the Beams in my Frame have axial force?

The beams in a lateral force resisting system, such as a braced frame or moment frame, typically carry a significant axial force. In the example below (with no diaphragms) the beam (M4) carries a significant axial tension. The axial force diagrams show that the beam (M4) is carrying 9.6 kips of tension (blue) because the beam is transferring the lateral force from brace M5 to M6. However, if a rigid diaphragm is created at the floor level then the axial force in M4 disappears: The question arises, how does the force now get from brace M5 down to brace M6? The answer is that the force is being carried entirely by the rigid diaphragm. See the image below, which explains why: If the explanation above isn’t clear, another way to consider this problem is to look at the movement of nodes. In a rigid diaphragm, none of the nodes are allowed to get any closer or farther away from each other, regardless of the load applied. In the example below, the distance “x” is always the same number. If it wasn’t then the diaphragm must have deformed (shrunk) in the x direction, but it can’t deform or shrink if it…

October 26, 2010 | RISA-3D, RISAFloor, RISA-2D, RISAFoundation, New, Data Entry, Spreadsheets

How to Use Spreadsheets More Effectively in RISA

RISA includes various advanced spreadsheet operations that make reviewing input and results easy. The features that we will focus on are available in the "Spreadsheet" tab located in the ribbon toolbar whenever a spreadsheet is open as well as by right-clicking in the table. P-Delta analysis is required in the AISC code, and it is something that you must specify on a per-load-combination basis. This is done by typing the letter Y in the P-Delta column of the Load Combinations spreadsheet. For those who aren’t familiar with the spreadsheet tools this can be a tedious task of typing the letter into every load combination. Instead, try doing this: click on the header of the P-Delta column to highlight the entire column in pink, click on the Block Fill button (the one on the right highlighted above) and have the program fill the block (group of currently selected cells) with the letter Y. Now let’s say that you’ve got a solution and you want to review your results, however you may have quite a few members to sort through. You want to quickly see which one has the worst case unity check. If you open up your Design Results spreadsheet you…