Need a book? Engineering books recommendations...
RE: 1997 UBC EQ Requirements[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
- Subject: RE: 1997 UBC EQ Requirements
- From: "Cain, William" <bcain(--nospam--at)ebmud.com>
- Date: Thu, 1 Jul 1999 09:54:02 -0700
Bruce- 1. Regarding the Near Source factor, Footnote 1 to Tables 16-S and 16-T allows linear interpolation between the 2 km and the 5 km distance, so you shouldn't have a step function as you go across a street. 2. For the OMRF designs, remember to consider the loading conditions in Section 2211.4 No. 3.1 (Equations 3-7 and 3-8) for LRFD or 2213.6 No. 2 for ASD. These provisions establish a pretty healthy penalty for OMRF connections. Regards, Bill Cain, SE Oakland, CA -----Original Message----- From: Parkerres(--nospam--at)aol.com [SMTP:Parkerres(--nospam--at)aol.com] Sent: Wednesday, June 30, 1999 22:54 PM To: seaint(--nospam--at)seaint.org Subject: 1997 UBC EQ Requirements To all: As you all know, the local Building Dept's here in Southern California (LA, etc.) are enforcing the 1997 UBC starting tomorrow (7/1). We are a firm that does primarily Type V (wood) structures with OMRF steel frames. I have been trying to get some feel from the local Cities as to what guidelines to follow, but they do not seem as well informed as one might like. Currently, we are going to go with the following approach. I would appreciate the comments of others before we head too far down the path. 1. Use "Simplified Static Design" per 1630.2.3 so that we can ignore all the fancy deflection checks, etc., required for regular "Static Design". This gives an equation of V = (3.0 Ca / R) / 1.4 W. 2. Assume Ca = 0.44 Na for worst case soil, Sd, without a soils report in seismic zone 4. 3. Assume Na = 1.3 for ALL of the LA area which assumes <2km from a Seismic Source Type B fault. We bought the special seismic zone map book, but it is hard for us to justify that some areas of LA need the 1.3 factor, but areas across the street can use Na = 1.0 since they are more than 2 km from a "known fault". Ironically, Northridge is squarely in one of the 1.0 zones. 4. Use R = 4.5 for light framed buildings or OMRF Steel Frames. 5. This yields: V = 3.0 * 0.44 * 1.3 / 4.5 / 1.4 = 0.272 W The 1994 UBC gave V = 0.183 W for similar worst case scenarios. This is a 49% increase in my loads! Comments? What is everyone else doing? Thanks for your input. Bruce Resnick, SE Parker Resnick Str. Eng.
- Prev by Subject: Re: 1997 UBC EQ Requirements
- Next by Subject: Re: 1997 UBC EQ Requirements
- Previous by thread: Re: 1997 UBC EQ Requirements
- Next by thread: Re: 1997 UBC EQ Requirements