1. P17 SDC* Working Group Meeting 2 *Seismic Design Category
W.G.
P17 SDC* Working Group Meeting 2 *Seismic Design Category
Julie C. Furr, PE, SECB
Senior Engineer
CSA Engineering, Inc.
Chair
P17 SDC Working Group

2. Outline Welcome Related Groups – Topic Summary
W.G.
Outline
Welcome
Related Groups – Topic Summary
P17 SDC Fundamental Task – Review
Revise SDC Definition?
Redefine SDC Parameters?
Open Discussion

3. Schedule Project 17 to be Complete December 31, 2017 W.G.
Next Meeting: November 29, 2016
3 Meetings in 2017
SDC Working Group
Initial Meeting: August 10, 2016
Meeting 2: November 4, 2016
Meeting 3: December 2017 (proposed)
Does the group prefer multiple short meetings or a face to face meeting before november? Expenses, productivity?

4. Related Groups – Topic Summary
W.G.
Related Groups – Topic Summary
PUC IT-01 (Pekelnicky)
Seismic Performance
Structures
Non-Structures
Map fluctuations
Accuracy and Precision Working Group (Dolan)
Accuracy of mapped values and fluctuations
Precision of reporting
Very broadly stated, P17 has discussed the issues…
So, we’re looking at the other side of the equation…

5. P17 SDC Fundamental Task-Review
W.G.
P17 SDC Fundamental Task-Review
P17 Discussions
Issues: Mapped ground motions fluctuate too much and reported accuracy on USGS web tool is misleading.
Solutions?
Can engineering community disregard USGS changes within a predefined margin (stated margin of error)?
Can ground motion fluctuations be flattened in some way?
Round off reported accelerations to predefined accuracy?
Most proposed solutions directed to the science and reporting of mapped values.
Working Group Creation
Alternate approach: Hold discussions to change how seismic design categories are designated.
Proposed approach directed to the engineering application without constraining the science.
Very broadly stated, P17 has discussed the issues…
So, we’re looking at the other side of the equation…

6. P17 SDC Fundamental Task-Review
W.G.
P17 SDC Fundamental Task-Review
Initial Task Highlights…
Define how Seismic Design Categories are decoupled from ground accelerations.
Broadly consider impacts on material standards and practical implementation.
What SDC boundary/definition would be most palatable (and therefore sellable) to adopting and enforcing jurisdictions?
Currently based on Sds/Sd1 as listed in Tables and in ASCE 7
Material standards: if we develop a perfect solution but it upends the ACI provisions, do we really want to go there?
Politics: we can develop a perfect solution to address science and engineering, but useless if governing jurisdictions amend standards to change=> latest AR amendment

7. P17 SDC Fundamental Task-Review Meeting 2
W.G.
P17 SDC Fundamental Task-Review Meeting 2
P17 Discussions
Issues: Mapped ground motions fluctuate too much and reported accuracy on USGS web tool is misleading.
Detailing requirements across the board are based on SDC.
Very broadly stated, P17 has discussed the issues…
So, we’re looking at the other side of the equation…

8. P17 SDC Fundamental Task-Review Meeting 2
W.G.
P17 SDC Fundamental Task-Review Meeting 2
Revise SDC Definition?
Fundamentally based on ground motion intensity correlated to PGA and PGV
Alternate means of defining hazard?
General Correlation
MMI V SDC A - No real damage
MMI VI SDC B - Light nonstructural damage
MMI VII SDC C - Hazardous nonstructural damage
MMI VIII SDC D - Hazardous damage to susceptible structures
MMI IX SDC E - Hazardous damage to robust structures
Very broadly stated, P17 has discussed the issues…
So, we’re looking at the other side of the equation…

9. P17 SDC Fundamental Task-Review Meeting 2
W.G.
P17 SDC Fundamental Task-Review Meeting 2
Redefine SDC Parameters?
SDC is currently determined based on site class, building occupancy and importance, and MCE accelerations.
Actual ground motion will vary only with site class.
Building occupancy and importance has no impact on ground motion.
Very broadly stated, P17 has discussed the issues…
So, we’re looking at the other side of the equation…

10. W.G.
Open Discussion
SDC’s must be defined in a way that will facilitate use and encourage adoption of codes without significantly increasing code complexity or fanning jurisdiction resentment already in existence, while still maintaining life safety.
have sugg approaches already ed in but wanted to get your ideas without influence first. Will send them out with meeting summary