Progressive Collapse Check of Existing Building - RISA or STAAD?
Progressive Collapse Check of Existing Building - RISA or STAAD?
(OP)
Project is a cast-in-place concrete building built in 3 stages (1942, 1944, 1955). I need to perform a progressive collapse check on it. Out of RISA-3D and STAAD, which program would be better suited to do this analysis on an existing structure? It seems to me that you do not put reinforcement into the RISA model, and you would in STAAD. All things being equal, I prefer RISA, its user interface is just more friendly.






RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
In the concrete building we did, it was a barracks and everything was an 8 inch wall so we justified the walls acting as very deep beams to transfer the load around a missing wall below. This was done easily by hand.
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
To do that sort of thing in a program that is essentially linear elastic (like RISA or STAAD) would be something of a challenge. You can probably do it... It's just more work and book keeping than you would be used to. Essentially, you'd be doing multiple seperate analyses and combining the results on your own (using Excel?) using principal of super position.
This type of analysis requires a lot of book keeping and can get pretty tricky. The programs that specialize in it (Perform 3D from CSI comes to mind) are sort of niche programs and tend to be relatively expensive.
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
Mike McCann
MMC Engineering
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
- Because the beams and columns are modelled with fibers representing the steel, confined concrete and un-confined concrete, no moment-curvature analysis is necessary to determine the properties of plastic hinges.
- Shear stress and strains are not modelled currently.
I only mention it because it is free and would be interesting to take a look at if a guy had a project to use it on.
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
But as long as it is possible to do in RISA, even if it requires keeping track of progress separately in Excel, that's the way we need to go. It's a very fast track program, and I don't have time to look into purchasing new software nor to become familiar enough with it for it to be an effective tool where I'm confident with the results.
You can't put in reinforcing, but you can use it as a 3D analysis tool, find the maximum +M and -M and compare it to the capacities of the beams in place.
Thanks for your help, everyone!
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?
RE: Progressive Collapse Check of Existing Building - RISA or STAAD?