UBC 97 Earthquake Questions
UBC 97 Earthquake Questions
(OP)
Hi,
I am reading the UBC 97 code to educate myself, and I found couple of statements which I don’t understand:
1 The UBC has categories A, B, C,… AND divisions I, II, III,..,,So how can I refer to these categories definitions in the code
2. 1629.8 Section is not clear, so literally speaking for 1629.8.4 dynamic
Does statement 1 include 2?
All of them are mix,Can’t pick it easily
So lease clarify in simple words, when to use static and when to use spectrum analysis.
3. In section 1630.1.1 he refer to columns common to two bays (so what this supposed to mean?)
4. I can’t tell form code that which combination to pick ultimate or service for the following
Overturning
Drift
However my personal judgment is
Overturning (Ultimate)
Drift (Service)
Thank you all
I am reading the UBC 97 code to educate myself, and I found couple of statements which I don’t understand:
1 The UBC has categories A, B, C,… AND divisions I, II, III,..,,So how can I refer to these categories definitions in the code
2. 1629.8 Section is not clear, so literally speaking for 1629.8.4 dynamic
Does statement 1 include 2?
All of them are mix,Can’t pick it easily
So lease clarify in simple words, when to use static and when to use spectrum analysis.
3. In section 1630.1.1 he refer to columns common to two bays (so what this supposed to mean?)
4. I can’t tell form code that which combination to pick ultimate or service for the following
Overturning
Drift
However my personal judgment is
Overturning (Ultimate)
Drift (Service)
Thank you all






RE: UBC 97 Earthquake Questions
1.a If you are referring to occupancy categories, there is a table toward the back of chapter 16 that defines the different occupancy categories. It is based on use and number of occupants.
1.b Chapter 16 of the UBC is divided into divisions: Division I - General Design Requirements; Division II - Snow Loads; Division III - Wind Loads; etcetera
2. A dynamic analysis is required when the building meets any one of the criteria in 1629.8.4.1 thru 1629.8.4.4. If any one of these criteria is met, a dynamic analysis is required. Also, if the building does not meet the requirements for static analysis in 1629.8.3, a dynamic analysis is required.
3. In general terms, a bay is the area (in plan) between 4 columns. When talking about frames, a bay is the area (in an elevation) between two columns. For moment frames, a column common to two bays has moment connections on opposite sides of the column.
4a I can't remember off the top of my head, For overturning, I believe you can use either strength of service provided the appropriate load combination is used.
4b. I believe drift uses ultimate (inelastic), see 1630.9.1 etcetera