Hello,
I have a 3 and 4 hr fire ratings in some electrical rooms, but can't find any information on clear cover to reinforcement on walls. Not in IBC code at least. Are there any references for this? Maybe it could be similar to columns? Didn't there used to be a prision that was clear cover =...
Hello,
Just wondering if etabs has anything equivalent to RISA 3D's soil compression springs, where I can easily input the subgrade modulus and Risa will automatically assign it accordingly to each of the four sides of the plates. What would be the etabs equivalent method to achieve this?
Is...
Hello,
I am relatively new using RAM concept and to PT design in general and I have a basic question.
I'm designing a two-way PT flat slab that's restrained on all four sides by walls. My understanding is that per code, these slabs are to remain Uncracked and all service stresses shall be...
Does anyone know if there's a valid procedure for calculating through bolts in a concrete wall loaded in shear?
I am kind of close to an edge, so that got me thinking about that. ACI-318 doesn't seem to address these. Maybe PCI? Any ideas?
What is the behavior of tilt wall panels that need to be stitched together for overturning? I.e. what forces should I design the shear plates for? How does shear flow thru the panels? Do you guys have any examples or design guides for these connections?
Thanks!
Hello,
I recently had a site with two different geotechnical reports (same site, two reports from different years) and the subsurface conditions were similar (depth of clays, bearing stratum, etc), but one of them used Chalk for the bearing stratum, and the other used Marl". Both were found at...
thread507-382979
Please reference http://www.eng-tips.com/viewthread.cfm?qid=382979
My question is why is RISA 3D still giving you a warning about exceeding 0.75Pc as specified in the moment magnification method if RISA is doing a pure elastic 2nd order analysis (NOT magnification method)? Is...
Hello,
I just wanted to see if any of you have a good reference for calculating the effective radius of gyration and the torsion properties of a built-up section (Cw, J, rts). The built-up section is composed of two wide flange beams on top of each other, connected with a continuous plate. I...
DaveAtkins,
JAE is right, that is the 0.2 factor I was talking about. For typical wind speeds, that 0.2 factor can become to be around 7-10 psf of additional load on your purlins. But then, you don't need to apply those loads on your girders as their tributary areas will most likely exceed the...
Per strength level combos, there is a load combination (1.2D+1.6Lr+0.5W) where the wind load is always additive to your worst case gravity loading on your roof. This wind load per components and cladding (i.e. for a joist or purlin) is always going to have a value that is around 0.2*wind load...
Hello,
Does anyone have any tips on how to apply roof wind pressures to a building in a gravity program i.e. RISA Floor? I just don't want to be overly conservative when applying components and cladding wind loads to joists and purlins, since I know that for girders, the trib area is way over...
Hello,
I am trying to model a flexible diaphragm (steel metal deck) as I need the lateral stiffness that this would provide to some elements that are not part of the lateral system.
To my understanding, there are two methods: Plate elements (semi-rigid) diaphragm and to model "X" braces to...
Thanks, Josh.
I was in a star seismic seminar not too long ago and they had some RISA 3D frames up in the screen with specific sections showing the KF designation and stuff like that. Is this the section database that you are talking about? Is that available in any version of RISA? or do we...
Hello,
Im starting with the design of a one story building with a rigid diaphragm (SDC D) and we are going to use buckling restrained braced frames.
Do you think risa 3D is a good software to do this? Are there any design tips for modeling the right stiffness of these frames? Any advice would...
Hello,
When applying different loading conditions for joists (not just distributed load, e.g. a point load or partial distributed loads). I know that RISA Floor will do the Uniform Load Method, which, I thought it was just getting an equivalent Uniform Load. My question is that it seems that...
Hi,
I am modeling a simple "benchmark" problem for a steel cantilever beam. My question is that in RISA 3D, when modeling the beam with a frame element with one end fixed and the other end free, I get a Cb value of 2.32 (calculated with equation AISC F1-1) taking into account the moment diagram...
Yeah, I would agree it needs to stay elastic, although it is not well specified in the code.
And seismic forces are inertial forces generated where there is a mass in the structure due to the ground acceleration. So the forces are generated at the diaphragm elevations and then work their way...
Thank you for your comments, I have a few other questions based on your responses:
The seismic force that is generated in the building is assumed to be distributed to the lateral resisting systems by the Diaphragm, so the seismic force will go from the diaphragm and into the MSFRS isn't it? So...
Hi,
I'm calculating the lateral deflections of my flexible (metal deck) diaphragm. My question is:
1. Do we have to use the Amplification factor and calculate inelastic deflections like it is done with the main seismic force resisting system?
2. If we don't have to apply Cd, is the diaphragm...
Thanks Josh,
Do you know if RISA is at least thinking to provide a stiffness for flexible diaphragms based on connection pattern and metal deck in the future? Or are there other reasons why they are not doing this?
