30 PROTA Symposium:
New Generation of Seismic Codes and New Technologies in Earthquake Engineering
Lessons Learned from the
Peer Review Process
Farzad Naeim Farzad Naeim, Inc.
Jack Moehle UC Berkeley
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
The Seismic Peer Review Panel (SPRP)
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• Purpose – To provide independent, objective, technical
review of any aspects that relate to seismic performance
• Conduct – EOR proposes criteria and designs to satisfy it
– The SSRP reviews EOR submittals for • Consistency with performance objectives
• Consistency with standards of practice
– A good review provides input that promotes resolution of comments in a collegial environment
– This is not the place to force your way of doing things
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Peer review
• The burden to demonstrate conformance
of the structural design resides with the
EOR.
• The responsibility for the structural design
remains solely with the EOR.
• The responsibility for plan review resides
with the Building Official.
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Peer review limitations
SPRP membership
Consultation
• Selected as individuals, not
companies • No conflicts, quid-pro-quos
Project Sponsor and EOR
Building
Official
SPRP
• SE – Tall building expertise
• Geo/Seismic Hazard
• Academic – Specific expertise
Selection,
Reporting
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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SPRP contracting models
Project Sponsor and EOR
Building
Official
SPRP
Selection,
Contract,
Reporting
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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SPRP contracting models
Project Sponsor and EOR
Building
Official
SPRP
Selection,
Reporting
Contract
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Operational aspects – kick-off meeting
Project Sponsor
Building Official SPRP
EOR
Points
of
contact
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Operational aspects – detailed work
Project Sponsor
Building Official SPRP
EOR
Points
of
contact
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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• SE
– Chair meetings, manage team, single point of contact for SPRP
– In-office support team reviews computer models and monitors comment log
– Prepares letters for approval by SPRP
• Geo/Seismic Hazard expert
– Seismic hazard representation
– Foundation modeling
• Academic
– Building-specific aspects
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SPRP (typical) distribution of work
• Review Design Criteria – design approach – seismic hazard
– modeling approaches
– acceptance criteria
– whatever else arises…
• Review early design concepts and details
• Review final design – computer input and output – analysis results in relation to design criteria
– details as expressed in drawings
• Participate in SPRP meetings
• Complete written reports/letters
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SPRP scope of services
• Peer review should facilitate the project development, not impede it
• Peer review should start early
• Stages
– Kick-off meeting
– Basis of Design (design criteria)
– Geo report / seismic hazard representation
– Excavation / Shoring /Foundation approval
– Partial or complete structural review
– Final approval letter
Timeline and deliverables
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Example of an Unrealistic
Schedule
Englekirk:
Englekirk:
AMEC:
AMEC:
SPRP
Englekirk:
General Contractor:
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1. Basis of Design document to be submitted to
SPRP:
By
To be submitted between September 15, 2014 and
September 30, 2014
2. Approval of Basis of Design document: By SPRP:
From September 16, 2014 to October 14, 2014
3. Submittal of response spectra to the SPRP: By
To be submitted between September 26, 2014 and
October 7, 2014
4. Approval of response spectra: By SPRP
From September 29, 2014 to October 8, 2014
5. Submittal of time histories to the SPRP: By
To be submitted between October 27, 2014 and
November 6, 2014
6. Approval of time histories: By
From October 30, 2014 to November 13, 2014
7. Submittal of Service Level Earthquake (SLE)
design calculations and drawings to the SPRP:
By
To be submitted between December 22, 2014 and
January 9, 2015
8. Approval of SLE design*: By SPRP:
From January 12, 2015 to February 9, 2015
9. Submittal of shoring and underpinning design: By
To be submitted between April 13, 2015 and
April 27, 2015
10. Approval of shoring and underpinning design: By SPRP:
From April 28, 2015 to June 8, 2015
11. Collapse Prevention Level Design and
submittal for the foundation permit drawings to
the City and the SPRP:
By
To be submitted between October 1, 2015 and
October 15, 2015
12. Review process and approvals to pull
foundation permit:
By SPRP:
From October 2, 2015 to December 1, 2015
• Basis of Design – Should be detailed and explain
• approach to design
• details of modeling and acceptance criteria
• Computer models – Help SPRP help you
• Member proportioning and details – For a foundation permit you should have an
essentially completed design
– In some cases you can get a conditional excavation permit without a complete design
• Performance verification
• Structural drawings
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Design Documentation
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering iv
Example BOD Table of Contents
3 Design process ............................................................................................................ 7
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6
3.1.7
3.1.8
Flexural design in walls.............................................................................. 9
Shear design in walls .................................................................................. 9
Special Structural Wall Reinforcement ....................................................... 9
Coupling beams .......................................................................................... 9
Punching shear in floor slabs ................................................................... 10
Structural Diaphragms ............................................................................. 10
Foundation ................................................................................................ 10 Non-core walls .......................................................................................... 10
4 Serviceability evaluation........................................................................................... 11
4.1 General .............................................................................................................. 11
4.2
4.3
4.4
4.4.1
4.4.2
4.5
4.5.1
4.5.2
4.5.3
Seismic Input .................................................................................................... 11
Load Combinations........................................................................................... 11 Mathematical model.......................................................................................... 11
Performance Check................................................................................... 11
Design Confirmation................................................................................. 12
Documentation.................................................................................................. 12
Design Quantities...................................................................................... 12
Service Level Analysis Model ................................................................... 12
Service Level Analysis Output .................................................................. 12
5 Collapse Prevention evaluation................................................................................. 13
5.1 General .............................................................................................................. 13
5.2 Seismic Input 13
5.3 Load Combinations 13
5.4 Mathematical model 13
2.3 Building Risk Category................................... ............. ....................................... 5
2.4 Materials of Construction .............................. .............
.
....................................... 5
2.4.1 Concrete .................................................. .............
.
...................................... 5
2.4.2 Reinforcing steel
.......................................
........... ....................................... 5
2.5 Stiffness properties.......................................... .................................................... 5
1
2
2.2
2.2.1
2.2.2
2.2.3
Code Exceptions ................................................................................................. 4
Structural height ......................................................................................... 4
Columns ...................................................................................................... 5
Foundation .................................................................................................. 5
v
5.4.8
5.4.9
5.4.10
Backstay Effects ....................................................................................... 17
P-D effects ................................................................................................. 18
Damping: .................................................................................................. 18 5.5 Performance Check........................................................................................... 18
5.6 Presentation of Design and Response Data ...................................................... 20 5.6.1
5.6.2
5.6.3
Design Quantities...................................................................................... 20 Nonlinear Time-history Analysis Input ..................................................... 20
Nonlinear Time-history Analysis Output .................................................. 20
6 Specific Provisions.................................................................................................... 22
6.1 Documentation of Concrete Proportions .......................................................... 22
7 Seismic Instrumentation............................................................................................ 23
Appendices..................................................................................................................... ... 24
A. PEER review information ........................................................................................ 24
B. Site Plan................................................................................................................... . 26
C. 3D views................................................................................................................... 28
D. Building Section....................................................................................................... 31
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Int Table of Contents
roduction 1
5.4.1 Computer model ........................................................................................ 13
1.1 Purpose................................................................................................................ 1 5.4.2 Concrete core walls .................................................................................. 13
1.2 Project Description.............................................................................................. 1 5.4.3 Basement walls.......................................................................................... 15
1.3 Design Approach ................................................................................................ 2 5.4.4 Coupling beams: ....................................................................................... 15 Ge neral 3 5.4.5 Diaphragms............................................................................................... 16
5.4.6 Modeling of Gravity System and Fl oor Slab Out-of-Plane Behavior 17
2.1 Codes and reference documents.......................................................................... 3 5.4.7 Accidental Torsion: (per LATBSDC 2014) 17
Example BOD Modeling Details
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Example BOD Modeling Details
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Example of Summarizing Results
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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The Comment Log # Page Date Comment Response Resolution
2 2-3 x/y/z The values of Z1.0
and Z2.5 listed on
these two pages
are not consistent.
The consultant
should clarify
which set of
values were used
in the analysis.
This has been corrected
in the attached revised
report (date)
Resolved
(date)
• Differences of opinion can arise
– level of complexity required for analysis
– interpretation of results
• Disputes are rare
– Building Official is final arbiter
– Advisory panels can be consulted
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Dispute resolution
• “The peer review process takes too long,
is too expensive, and too uncertain.”
– Example 1: The dual system that was not
– Example 2: The dual system that became one
– Example 3: Armed struggle over stress limits
– Example 4: SPRP’s suspended animation
– Example 5: Conditioning payment on
Approval
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Examples
• Example 6 – Spectrum-matched versus
scaled motions
Ground motion selection and scaling
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• Example 7 – Conditional mean spectra
– Example 7a
– Example 7b
Ground motion selection and scaling
Figure courtesy of Prof. Jack Baker
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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• Example 8a – What do you mean the
effective damping is 2.5% of critical?
• Example 8b – Rayleigh damping scaled
for T1 through T3.
• Example 8c – Modal damping
Nonlinear dynamic analysis
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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• Example 9 – Strain capacity of unconfined concrete is
0.003. Therefore, no confinement should be required if e c
< 0.003.
Demand versus capacity
0.25 0.50 0.75
Distance along web from flange / lw
Flange in tension
Co
ncre
te s
train
0.015
0.005
-0.015 0.00
Flange
0.010
0.000 -0.005 -0.010
1.00
Stem
Drift Ratio
0.75%
1.00%
1.50%
Meas. Calc. Lateral
loading
Thomsen and Wallace (2004).
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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• Example 10 – The loop-de-loop hoop.
Structural detailing
Loop-de-loop hoop
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Daisy chain of loop-de-loop
hoops as reinforcement for
wall shear, confinement,
and reinforcement support
• Example 11 - Diagonally reinforced coupling beams –
The entire shear is carried by the diagonals, therefore
the concrete outside the diagonals is not required.
Structural detailing
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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• Example 12 – Wall-slab interfaces?
Construction details
10 ksi
4 ksi
10 ksi
10 ksi
4 ksi
10 ksi
10 ksi
4 ksi
10 ksi
10 ks
4 ksi
10 ks
(a) Probable
code violation
(b) Puddle wall
concrete into slab
(c) Hold back
slab concrete,
cast wall through
the slab
(d) Slip form the
wall
Cold joint
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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• Example 13 – Unit shear strength of members without
shear reinforcement is known to decrease with
thickness. Should a foundation mat have shear
reinforcement?
Foundation mats
30 PROTA Symposium: New Generation of Seismic Codes and New Technologies in Earthquake Engineering
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Thank you!
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