Need a book? Engineering books recommendations...
RE: Seismic Lateral Load[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: SEAOC <seaoc(--nospam--at)seaoc.org>
- Subject: RE: Seismic Lateral Load
- From: "Nickel, Patrick" <PNICKEL(--nospam--at)PARAGONSTR.COM>
- Date: Sat, 2 May 1998 14:43:00 -0700
- Encoding: 41 TEXT
I think the most important thing is to apply loads the way they will be applied to the structure. It doesn't make sense to me to have your computer design for heavy axial loads in a beam only because you applied the seismic load to one end of a long frame. It also doesn't make sense to ignore forces in collectors when you have a short frame in a long continuous framing line. Lastly, it doesn't make sense to design the second floor collectors for half the force of the third floor collectors, when the UBC requires that the diaphragms be designed for similar loads (1994 UBC section 1631). In summary, you should understand the building better than the computer, and design and detail according to what you think is correct, not according to what the computer spits out. Skill of computer modeling is getting the computer to agree with you - if indeed your assumptions are valid. Patrick Nickel, SE ---------- From: Geoffrey G. Melchor Thanks Christopher, that's also one of the things that I'm planning to do. Geoffrey Christopher Wright wrote: > >Do I have to apply > >the Fx (determined node load)to all joints at the same level or divide > >the Fx by the number of joints on that same level. > This is a good rule for any finite element software when you're not > absolutely certain how it will apply loads-- > Make a simple model with loads applied the way you suppose they should > go. Check the reaction forces and moments (all six equilibrium equations) > against what you think the input loads should be. If the reactions > equilibrate the applied loads within 5 significant figures, you got it > right. Checking within three significant figures is usually ok, but might > want further checking (like the effect of arcs modelled as chords) to > make sure it's not an input error. Less than three figures means bad > software or input problems. > > I've found hundreds of my own (and other people's) mistakes, program bugs > and documentation errors this way. And, 30 years after my last mechanics > class, boy, can I draw free-body diagrams. ;-> > > Christopher Wright P.E.
- Prev by Subject: Re: Seismic Lateral Load
- Next by Subject: Re: Seismic Lateral Load
- Previous by thread: Re: Seismic Lateral Load
- Next by thread: Re: Seismic Lateral Load