ACI COMMITTEE 369 - American Concrete Institute
Transcript of ACI COMMITTEE 369 - American Concrete Institute
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ACI COMMITTEE 369 SEISMIC REPAIR AND REHABILITATION
2015 ACI Spring Convention Kansas City, MO
April 13, 2015
2:00 p.m.– 6:00 pm Meeting Minutes – Meeting 3
Members Present: See Appendix 1.
Visitors: See Appendix 1.
1. Welcome and introductions Wassim Ghannoum welcomed the audience, and reviewed the agenda.
2. Approval of Meeting Agenda Moved: Adolfo Matamoros; Second: Jeff Dragovich.
3. Approval of Minutes from Spring Meeting Minutes from the 2014 Fall meeting in Washington DC were approved as presented (posted on committee
webpage).
Moved: McCabe; Second: Dragovich; Abstain: Kenneth Luttrell
4. Update Wassim Ghannoum discussed the 8 substantial technical changes that the committee is planning to pursue
during the summer 2015. Each technical change will be investigated by a separate group. Ghannoum
encouraged committee members to contribute to at least one technical change.
5. ACI 369 and ACI 440 Collaboration In the last meeting, ACI 440 proposed a seismic chapter that some of the ACI 369 committee members
reviewed. The committee members agreed that ACI 369 committee should continue working with ACI
440 to assure that our documents will work well together. Moreover ASCE/SEI41 needs to propose tables
for m-factors and modeling parameters of retrofitted members, emphasizing the need for collaboration
between ACI 440 and ACI 369 committees.
6. ACI 369 and ACI 562 Collaboration Jim Stevens gave a presentation about ACI 562 activities to find the opportunities for collaboration
between ACI 369 and ACI 562. ACI 562 is writing a code document that will be published next year.
This building code will be similar to ACI 318, but for existing buildings, and is aimed to be used as a
standalone provision that also works well with the IEBC. Since both ACI 369 and 562 deal with existing
buildings, these documents need to be consistent. Stevens suggested forming a committee from members
of both committees to work on mutual topics and provide a list of items and goals for collaboration.
7. Task Groups for Technical Changes Wassim Ghannoum talked about the subcommittees for 8 technical changes that the ACI 369 committee
will make over the next summer. Four main task groups are already formed (See Appendix 2). Wassim
Ghannoum asked the committee members to sign up for at least one group. Most of the technical changes
will be balloted before August 2014. The first iteration of comments from balloting process will be
discussed in the summer meeting. The technical changes will be reballoted after the summer meeting, and
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the remaining issues will be resolved at the November convention. Further discussions were made on the
following technical changes:
7.1. Moment Frame Task Group: Update the Modeling Parameters of Beams
Adolfo Matamoros reviewed the beam proposal. He noted that the current beam modeling
parameters in ASCE/SEI 41 are from FEMA 356, and in contrast to columns, have not been
updated for a long time. His task group will develop new tables for nonlinear modeling
parameters and acceptance criteria of beams.
The ballot did not pass due to insufficient votes. Proposed resolution to negative votes are
presented in Appendix 3.
7.2. General Provisions Task Group
Insung Kim reviewed the future proposed changes, as follows:
- Minimum testing requirements for anchors: ASCE 41 does not have minimum testing
requirements for anchors. This issue may become a concern for wall-to-diaphragm anchors in
existing buildings, as they may be in the load path of the structure, and currently there is no
quality control for these components. As a result, ACI 369 needs to develop a set of minimum
testing requirements for the anchors.
- Tension in columns and walls: Please see the discussion in the minutes from the ACI 369 meeting
on 04/12/15 (first day of the convention).
7.3. Shear Walls Task Group
- Stiffness of the walls: Garret Hagen was selected to form a team to investigate various approaches
to compute the flexural stiffness of the wall.
- Modeling Parameters and Acceptance Criteria of slender walls: Anna Birely will update the
tables for modeling parameters and acceptance criteria of slender walls. Her group will also
clarify the use of shear controlled versus flexure controlled walls. Moreover, the m-factors of the
shear controlled walls will be updated.
7.4. Retrofit Techniques Task Group
- Developing tables for Modeling Parameters and Acceptance Criteria of jacketed columns: Sergio
Breña will develop a set of tables for modeling parameters and acceptance criteria of rectangular
and circular jacketed columns based on his ongoing work with his Ph.D. student.
Break (20 minutes)
During the break committee members signed up to participate in at least one task group (See Appendix 2).
The meeting was reinitiated at 4:30 p.m.
8. Reviewing Ballots on the Wall Sections Anna Birely reviewed the balloting results on the wall section and discussed a few negative votes on
the usage of the word “measured” material properties and notations used in the wall section.
The ballot did not pass due to insufficient votes. Proposed resolution to negative votes are
presented in Appendix 4 and Appendix 5.
9. Reviewing Ballots on the General Provision and Notation Sections Adolfo Matamoros reviewed the balloting results on the general provisions for the frame section. Most of
the comments and changes were on the clarification of parameters used in ASCE/SEI 41. The ballot did
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not pass due to insufficient votes. Proposed resolution to negative votes are presented in
Appendix 6. There was further discussion regarding the clarification needed on the parameters used in the computation
of strength. The main focus was on distinguishing between the expected and lower bound material
properties in classification and strength determination of columns. Several options were discussed to
address this issue as outlined in the minutes of the April 12 committee meeting.
The ballot for the notations did not pass due to insufficient votes (see Appendix 7). The change
proposal will not be re-balloted again. Notations will be handled in each subsequent ballot
separately.
10. Summer Meeting First and second week of August were chosen for scheduling the summer meeting. The location of the
meeting will be determined later.
11. Adjournment Moved: Izquierdo; Second: Breña.
Minutes respectfully submitted by: Siamak Sattar.
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Appendix 1: List of Attendees on 04/13/2015 Meeting
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Appendix 2: List of Task Groups and Change Proposal Groups
1 2 3 4 1 2 3 4 5 6 7 8
General Frames Walls Retrofit Columns Beams Joints Anchors Tension wall stiff wall MP Retrofit
Wassim Ghannoum x x x x x x
Siamak Sattar x x x
TAC Contact
Andrew Taylor
Anna Birely O x x
Sergio Brena O x
Casey Champion x x x
Jeffrey Dragovich x
Kenneth Elwood x x
Una Gilmartin x x
Arne Halterman x x x
Wael Hassan x x x x
Mohammad Iqbal x
Jose Izquierdo-Encarnacion x x
Afshar Jalalian x
Thomas Kang x
Dominic Kelly*
Insung Kim O x x x
Laura Lowes x x x x x
Kenneth Luttrell x x
Adolfo Matamoros O x x
Steven McCabe x x
Murat Melek x x
Jack Moehle
Arif Ozkan x x x
Robert Pekelnicky x x
Jose Pincheira x x x
Mario Rodriguez*
Murat Saatcioglu*
Halil Sezen x x x x
Roberto Stark x x x x
Andreas Stavridis*
John Wallace x x
Tom Xia x x x x
Sergio Alcocer
David Bonowitz
Charles Hookham
Shyh-Jiann Hwang
Regan Milam
Andrew Mitchell
Raj Valluvan
Dave Beh
Thomas Bush
Julian Carrillo
Sushil Chauhan
Methee Chiewanichakorn
C Terry Dooley
Anindya Dutta
Simon Foo
Sigmund Freeman
Juan Fuentes
Aysegul Gogus
Garrett Hagen x
Consulting Members
Associate Members
Task Group Change Proposal
Voting Members
Officers
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John (Jack) Hayes
Guillermo Huaco-Cardenas
Mohammad Jalalpour
Brian Knight
Hung-Jen Lee
Andres Lepage
Gang Lu
Leonardo Massone
Yi-Lung Mo
Abbas Mokhtar-Zadeh
Mark Moore
Vilas Mujumdar
Aniruddha Nakhawa x x
Sarah Orton
Dan Palermo
Owen Rosenboom
David Sanders
Mehrdad Sasani
Drit Sokoli
Ying Tian
Michael Valley
John Viise
Jacqueline Vinkler
Ashkan Vosooghi
Travis Welt
Sarah Witt
Meagan Young
Kumars Zandparsa *The committee member has not expressed the areas where he will participate.
Note: Symbol “o” shows the leader of the task group.
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Appendix 3: Resolutions to Ballot Comments and Negatives (CH.17)
Last Name
Item No.
Page No.
Line No. N,
A/C Voter Comment Resolution / Vote Count
1. Kim CH17 103-107 C
Mnc_exp and Mnb_exp
should be defined in Ch.
14 (notations) as well
Noted
2. Kim CH17 General C
ASCE 41 does not use
nominal capacities with
subscript of “n” (e.g. Vn
or Mn) or factored design
forces with subscript of
“u” (Vu, Mu or Nu).
Subscripts “CE” & “CL”
are used for capacity side
and “UD”& “UF” for
demand side.
Subscripts should
correspond to the ASCE
41. For example, Vn,exp
should be VCE.
Changed: CE Capacity based on expected material properties, CL Capacity based on lower Bound, UD Deformation controlled actions), UF force controlled actions
3. Kim CH17 355-356 N
Is “fc’ str” lower bound
or expected strength?
Clarification should be
provided.
Notation changed to fc’,C and clarification added
4. Brena CH17 9 249-250 N
In the following
sentence, the limits
coll,
not ap.
“The database used to
assess the probability of
failure for parameter bp
includes columns with ap
≤ 33. Use caution when
applying the values from
Table 12 to columns with
ap > 33.”
corrected
5. Brena CH17 11 304 N
The reference in the
sentence should be to Eq.
4 instead of Eq. 3
corrected
6. Brena CH17 23 655-658 N
The current definintion
of Vc exp in the standard
does not include
punching strength of
slabs. This section refers
to the punching strength
Notation changed in the document to address Vo and shear strength.
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Last Name
Item No.
Page No.
Line No. N,
A/C Voter Comment Resolution / Vote Count
of slab-column
connections. Either a
different notation should
be used here or the
definition expanded to
include punching shear
strength of slab-column
connections (ACI 318
Section 22.6.5). Is it Vo,
exp? (see notation)
7. McCabe 6 175-184
Both places refer to
added equations and
terms:
The term Nu is taken
from ASCE 41 and is
based on expected axial
loadings. While this term
does match that found
ASCE 41 it can be
confused with the ACI
318 term, which is based
on fully factored design
loads. This seems to be
potentially confusing. Is
this correct as stated?
Perhaps a change in
subscript might be in
order?
The terms Mu/Vud is
proposed which appears
to be the fully factored
moment and shear design
values, if one applies
ACI 318. However,
ASCE 41 is based on
expected loadings and
uses M/Vd without the
subscript u. This is
inconsistent in my
opinion and potentially
confusing.
Notation changed
8. McCabe 10 302-311 Same as above Notation changed
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Last Name
Item No.
Page No.
Line No. N,
A/C Voter Comment Resolution / Vote Count
9. Ghannou
m CH17 4 103-107 C
Change notation to Mnce and Mnbe to be consistant with notation elsewhere such as Fye and FyL
Notation changed
10. 6
145-6 159 162
165-7, 172 …
C Change notation to Vne, Vpe
Notation changed
11. 7 174 N
I prefer to have the equation not in commentary but in the body of the code along with definitions. Perhaps equation 4 and 3 can be merged into one. with a general Vn equation then Vne= Vn with expected material properties, VnL = Vn with lower bound material properties. Specify VnL for force controlled, Vne for deformation controlled I agree with allowing ACI 318 shear strength equation ot be used (line 190) it should be kept in the re-organization. Change other term subscripts accordingly.
Equation was moved to the code as suggested. Changes were made to the notation to address comments about expected and lower bound material properties.
12. 6 146 N
Vpe should be defined better. This is suggested: … “shear demand at the expected flexural strength of plastic hinges…” in the commentary one should add that using ACI 318 1.25fyL approach is valid. In the notation section the definition should also
Prefer to leave it as is but open for discussion. With the changes made, the calculation of Vp, now defined as VUF, will be made on the basis of expected material properties.
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Last Name
Item No.
Page No.
Line No. N,
A/C Voter Comment Resolution / Vote Count
reflect this and specify that hardening should be accounted for.
13. 174 C F’ce instead of f’c,exp Notation changed
14. C F’c,str should be f’cL (lower bound)
Notation changed
15. Rodrigue
z 6 160
The condition of shears in line 160 page 6 seems need an upper limit and isn't this condition similar to the one shown in line 163. Please clarify. The documents should show the background of Equation 3 for shear strength including a comparison or predicted and measured shear strength in tests of RC columns. How the reader decides using either Eq 3 or the shear strength equation given by ACI 318 Chapter 18?
Clarification was added. The information requested is provided in the reference cited. The use of ACI 318 equations was clarified.
16. 219
Regarding the probability of failure Pf mentioned in line 219 how the document shows that this is a reliable figure for Pf?
This information was published in a paper in earthquake spectra and a peer report. Those are cited in the document
17.
Why the numbering of Eqs using letter-number C1 and C2 in page 9 when previous equation are referred to numbers? Why Table C1 and not Table 23?
The notation C is intended to refer to the commentary. Equation 3 was moved from the commentary to the main text in response to another reviewer comment so now the numbering is consistent.
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Appendix 4: Resolutions to Ballot Comments and Negatives (CH.18)
No.
Last Name
Item No.
Page No.
Line No.
N, A/C
12. Comment 13. Response
18. Kim CH18 100 N
“ or measured” should be deleted. By
definition (ASCE41-13, 7.5.1.4),
expected strength is the mean of
measured values from the material tests
(Or default LB or nominal strength x
multiplier).
Agreed. “or measured”
19. Brena CH18 8 158 A/C “of 0.5 times the … Agreed and revised
per comment.
20. Brena CH18 9 159 N
Coordination with other chapters is needed to use the same notation for modeling parameters (a, b, c). The moment frame chapter uses ap, bp to refer to points in the nonlinear backbone curve to distinguish these parameters from the a and b used in ACI 318. We need to be consistent.
Agreed. Subscripts nl have been added to the modeling parameters
21. Brena CH18 9 170 N
See comment above. There will be a notation conflict with the definition of d in ACI 318. Should be dp, but this is used for prestressed concrete beams in ACI318. This also affects the notation chapter.
Agreed. Subscripts nl have been added to the modeling parameters
22. Brena CH18 15 308 A/C Replace shear wall with structural wall. Agreed and revised per comment.
23. Rodrigu
ez CH18 165 A/C
Regarding lp in line 165 some wording is needed advising the reader that the suggested values might be gross measures of this parameter.
Will be addressed in future ballot addressing revision of modeling parameters.
24. Rodriqu
ez CH18 15 299 A/C
Regarding wall boundary elements in line 299 the wording "elements may be an effective measure..." should read "elements is an effective measure..." The reason is that this document should emphasize on the importance of using wall boundary elements for a significant improvement of a wall's seismic response.
The language "may be" is consistent between all suggested retrofit measures. Consistency should also be maintained with other chapters. No changes have been made.
25.
Huaco-Cardenas Guillermo D
CH18 non
voting
The inclusion of FEMA 440 (2005) - Improvement of Nonlinear Static Seismic Analysis Procedures would be a good reference to be used specially for 7.2.2.2 Nonlinear Static and 7.2.2.3 Nonlinear Dynamic Procedure.
Will be addressed in future ballot addressing revision of modeling parameters.
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Appendix 5: Resolutions to Ballot Comments and Negatives (CH.19)
No.
Last Name
Item No. Page No.
Line No.
N, A/C 14. Comment 15. Response
26. Brena CH19 7 119, 121
N
Coordination with other chapters is needed to use the same notation for modeling parameters (a, b, c). The moment frame chapter uses ap, bp to refer to points in the nonlinear backbone curve to distinguish these parameters from the a and b used in ACI 318. We need to be consistent.
Agreed. Subscripts nl have been added to the modeling parameters
27. Brena CH19 7 124, 126
N
There will be a notation conflict with the definition of d in ACI 318. Need to find a new way to define d for the backbone curves. The notation chapter uses dp, but this will conflict with the effective depth of prestressing reinforcement in ACI 318.
Agreed. Subscripts nl have been added to the modeling parameters
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Appendix 6: Resolutions to Ballot Comments and Negatives (CH.16)
No. Last Name Item No.
Page No.
Line No.
N, A/C
16. Voter Comment Resolution / Vote Count
1. Kelly CH16
19 12
A/C
I recommend eliminating “as well as chemical bond.” ACI 408 indicates that bar slip eliminates the chemical bond before the mechanical bond is engaged. Therefore, current equations are only accounting for mechanical bond.
Agreed. (update required.)
2. Rodriguez CH16
13 20
C
References in this section for combined strength under uniaxial or biaxial bending with axial load need to be updated. Restrepo et al. (2013) have proposed a simple procedure for computing the probable moment strength of rectangular and circular columns for both uniaxial and biaxial bending with axial load. Restrepo J., and Rodriguez, M., (2013),“On the Probable Moment Strength or RC Columns”, ACI Structural Journal, V. 110, No. 4
Please provide task group/ committee change proposal. Future work. Mario to submit change proposal
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Appendix 7: Resolutions to Ballot Comments and Negatives (CH.20)
No. Last Name Item No.
Page No. Line No.
N, A/C
17. Comment
3. Ghannoum CH20
89 C Should add a definition for - Expected Material
Properties: material properties obtained in accordance with Section 2.2.
4. Ghannoum
C If the above definition is added remove “or
measured” in Vce, Vne, Vpe, etc
5. Ghannoum CH20
C Make sure to update notations as per other
chapter changes due to ballot responses
6. Ghannoum CH20 C F’c,lb should be f’cL
7.
Ghannoum
CH20
C
Definition of m, add at the end: “m-factors are provided in tables providing numerical acceptance criteria for linear procedures for various members”
8. Ghannoum CH20 N Definition of my: remove Eq1.
9. Ghannoum
CH20 C Definition of k (kappa): add at the end: “, ASCE
41 Sections 5.2.6 and 6.2.4.”
10.
11. Kim CH17 103-
107 C
Mnc_exp and Mnb_exp should be defined in
Ch. 14 (notations) as well
12. KIM CH
20 N Section 14.2
Mnc_exp and Mnb_exp should be defined.
13.
KIM CH
20
N
Section 14.2
“ or measured” should be deleted in the
definitions of all the expected material strengths.
By definition (ASCE41-13, 7.5.1.4), expected
strength is the mean of measured values from
the material tests (Or default LB or nominal
strength x multiplier).
14. KIM CH
20 N Section 14.2
Is “fc’ str” lower bound or expected strength?
Clarification should be provided.
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Ghannoum CH20 89 C Should add a definition for - Expected Material Properties: material properties obtained in accordance with Section 2.2.
51 C If the above definition is added remove “or measured” in Vce, Vne, Vpe, etc
52 C Make sure to update notations as per other chapter changes due to ballot responses
53 C F’c,lb should be f’cL
54 C Definition of m, add at the end: “m-factors are provided in tables providing numerical acceptance criteria for linear procedures for
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No. Last Name Item No.
Page No. Line No.
N, A/C
17. Comment
various members”
55 N Definition of my: remove Eq1.
56 C Definition of k (kappa): add at the end: “, ASCE 41 Sections 5.2.6 and 6.2.4.”
57 C
Definition of m, add at the end: “m-factors are provided in tables providing numerical acceptance criteria for linear procedures for various members”