Model dynamic blast loads on a building frame in RISA 3D

[bf343]

We are working on a project at a Petrochemical facility where we need to reinforce an existing building to resist the blast loads from an accidental explosion on site. a blast consultant performed a blast study of the facility and has provided us with a reinforcement concept, blast loading pressures, impulses and duration's for the walls and roof. I have performed the component designs with SBEDS, but the lateral frame system of the building needs to be checked by a FEM model.

Does anyone know how to apply or model blast loads in RISA 3D? Are there any tutorials or videos available for this? From a google search, I find references to using RISA for blast loads, but no help is actually applying it.

Thanks

 

[JoshPlumSE]

Unfortunately, I'm not too well versed in blast load analysis. I know my old company had a design procedure document for it. But, I never read it in detail. Then post Oklahoma City, someone set me some CD's with some newly developed reference material. But, I can't honestly say that I've reviewed them in any detail.

My impression is that blast loading analysis is usually either a non-linear analysis (i.e. considering material yielding and hinging) or a time history analysis or possibly BOTH. If that's true then RISA is not the proper program to do this.

Of course, many of these complex non-linear analysis procedures will have a conservative linear analysis option as well. If you've seen references to RISA used for blast analysis then that is probably what they were doing. I do recall one user some years ago talking about his model as being a government building where he need to consider blast loading in the analysis. If I remember correctly, what he was doing was removing a critical column here or there in his structure and then running the analysis to make sure the adjacent frames were strong enough to take the re-distributed loads. The idea being that if any one load bearing element were destroyed that the building would still be strong enough to survive.