seismic risk assessment & resilient design of brbf buildings … · 2019-06-13 · seismic risk...
TRANSCRIPT
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Seismic Risk Assessment & Resilient Design of BRBF Buildings
using the FEMA P-58 Analysis Method
Presented by: D. Jared DeBock, PhD, PEAssistant Professor of Civil Engineering @ CSU, Chico
Senior Research Engineer @ Haselton Baker Risk Group (SP3)
Presented on Behalf of: The Full SP3 TeamCurt B. Haselton, Jack Baker, Katie Wade, Ed Almeter,
Shaunt Kojabashian, Mike McGlone, Tracy Rice, and Dustin Cook
SP3 | where research meets practicewww.hbrisk.com
NASCC Technical Presentation | April 3, 2019
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Motivation – What we get from code-based design, and current pushes for “functional recovery” design FEMA P-58 analysis methods for assessing resilience
(losses and downtime) Research to enable accurate FEMA P-58 analysis for
BRBF buildings Approaches to resilient design of BRBF buildings Summary and Q&A
Agenda for Today
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Motivation – What we get from code-based design, and current pushes for “functional recovery” design FEMA P-58 analysis methods for assessing resilience
(losses and downtime) Research to enable accurate FEMA P-58 analysis for
BRBF buildings Approaches to resilient design of BRBF buildings Summary and Q&A
Agenda for Today
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Code Design (ASCE7, etc.) Safety Goal – Yes (divides for demands by R and results in a
“safe but disposal” building)
“Performance”-Based Design (ASCE 41, SF AB 083, etc.) Safety Goal – Yes Also enhanced modeling and design scrutiny
“Resiliency”-Based Design (and Risk Assessment) Safety Goal – Yes Repair Time Goal – Yes Repair Cost Goal - Yes Also enhanced modeling and design scrutiny
Current Seismic Design Methods
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What is Code-Based Design Providing?
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15%
50%
Performance expectations for a sample building 8-story office building Northridge, CA Performance estimated from FEMA P-58 and the SP3-
RiskModel
8 mo.
> 1 yr.
Example Code-Conforming Building
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Repair Costs for Various CA Cities
New 8-story office building at 12 CA cities
~5-20%~10-80%
Design Event Rare Event
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New 8-story office building at 12 CA cities
7-10 mo.
7-18 mo.
Design Event Rare Event
Downtime for Various CA Cities
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Performance of CA Buildings by Location
Loss for the 10% in 50 year Hazard
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Summary for a wide range of building types: Safety: Expected to be safe (per 1989 and 1994
experience), but this was not assessed in this study. Losses: 5-25% mean loss for design event and 10-80% loss
for rare event (huge range!). Downtime: 6-12 months for design event and up to 2
years for rare event (substantial predicted downtimes!).
Summary of Expected Performance
Hence, we refer to these buildings as safe but
disposable for a rare event!
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Summary of Expected Performance
Why are we seeing expected damage/closure and performance that is inconsistent by location?
Code design objectives: Safety: “Safe” at the MCE Losses: Not considered for Cat. II, some for Cat. IV. Downtime: Not considered for Cat. II, some for Cat. IV.
Resulting basic design philosophy: Allow structural damage by using 1.0/R with ductile members. Allow non-structural damage (by using 1.0/R or not designing to
prevent damage).
Should we be considered loss/downtime in design?
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California Assembly Bill 393 – “functional recovery” code provisions for California NEHRP Reauthorization – Congress tasked NIST with
recommendations for design for functional recovery Cities like San Francisco – considering enhanced design
requirements for tall buildings (to consider functionality)
A Push for Resilient Design (Functional Recovery)
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Motivation – What we get from code-based design, and current pushes for “functional recovery” design FEMA P-58 analysis methods for assessing resilience
(losses and downtime) Research to enable accurate FEMA P-58 analysis for
BRBF buildings Approaches to resilient design of BRBF buildings Summary and Q&A
Agenda for Today
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FEMA P-58 is a probabilistic performance prediction methodology (15 year, $16M+ invested, ~100+ on the team)
FEMA P-58 is tailored for building-specific analysis (in contrast to most risk assessment methods)
FEMA P-58 output results:• Repair costs• Repair time• Safety: Fat & Injury
FEMA P-58: Overview
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FEMA P-58: Overview
Ground Motion Hazard
Component DamageEconomic Loss
Casualties
Repair Time
Structural Response
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FEMA P-58: Benefits
Comprehensive and credible: $16M, 15 years to develop, team of 100+ really smart researchers and practitioners. Standardized and repeatable: Consistent FEMA P-58 damage and
repair cost databases are used consistently for all analyses (created based on 20+ years of research). Building-specific: The analysis incorporates the specific nuances
of the building, rather than being based on a building class. Transparent and open-source: FEMA P-58 is open to the public
and you can see all the details of how the assessment is done.
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FEMA P-58 provides the comprehensive and standardizedbuilding-specific risk assessment.
SP3 software provides a user-friendly software to integrate all steps in a
FEMA P-58 risk assessment.
The initial assessment should take a couple hours and not days or weeks.
FEMA P-58 and Enabling Software
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Site Hazard Structural Responses
Structural Components &
Fragilities
Nonstructural Components &
Fragilities
Building-Specific Vulnerability Curves
Full distributions of losses and repair
times, and expected annual values.
FEMA P-58 Monte Carlo Analysis
ENGINE
FEMA P-58: Detailed Steps of Method
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FEMA P-58: Ground Motions
Step 1: Define ground motion hazard (with soil)• Option #1: SP3 can provide curve (given an address)• Option #2: User-specified curve
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FEMA P-58: Structural Response
Step 2: Predict “engineering demand parameters”
• Story drift ratio at each story• Peak floor acceleration at each
floor• For wall buildings, also wall
rotations and coupling beam rotations
Option #1: Response-history structural analysis
Option #2: Statistically calibrated predictive equations (**and we will need to extend these for BRBFs**)
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FEMA P-58: Component Damage
Step 3: Quantify component damageFirst, establish what components are in the building. Types and quantities can be specified or estimated from building size and occupancy type
Windows Piping
Partitions Structural components
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We end up with a list of component types, quantities and locations
FEMA P-58: Component Damage
Step 3: Quantify component damage
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Each component type has a “fragility function” that specifies the probability that a structural demand causes damage(**and we will need these for CoreBrace BRBFs**)
FEMA P-58: Component Damage
Step 3: Quantify component damage
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FEMA P-58: Consequences of Damage
Fragility functions have been calibrated for hundreds of components from test data, and repair cost and labor has been developed by cost estimators.
Cost per 100 ft. Labor per 100 ft.
Cracked wallboard $2,730 24 person-hours
Crushed gypsum wall $5,190 45 person-hours
Buckled studs $31,100 273 person-hoursThese are median values—each also has uncertainty
Step 4: Quantify consequences of the component damage (component repair costs, repair times, etc.).
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FEMA P-58: Building-Level Consequences
Repair costs are the sum of component repair costs (considering volume efficiencies)
Recovery time is aggregated from component damage, but is more complex (mobilization, staffing, construction sequencing, …)
Windows $26,892
Partitions $43,964
Piping $5,456
Structural Components
$77,920
… …
Sum = $253,968
Step 5: Aggregate to building-level consequences
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FEMA P-58: Monte Carlo Simulations
For a given building and ground shaking intensity, repeat the following steps 2,000-10,000 times!
1. Simulate each structural response parameter2. Simulate damage to each component3. Simulate repair costs and repair time for each component4. Aggregate to compute total repair cost and recovery time
We can then look at the mean cost, 90th percentile, etc.
Step 5: Aggregate to building-level consequences
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FEMA P-58: Summary
Step 1: Site Hazard• Soil and hazard curve• Ground motions (if needed)
Step 2: Structural Responses• Option #1: Structural analysis• Option #2: Predictive equations
Step 3: Damage Prediction• Contents and Components• Fragility curves
Step 4: Loss Estimation (loss curves & other consequences)
Step 5: Aggregate to building-level consequences
Thousands of Monte Carlo simulations
The simulations provide detailed statistical
information on building performance.
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8%
70%
16%
0% 3% 3% 0% 0%0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
StructuralComponents
Partitions InteriorFinishes
Cladding Plumbing andHVAC
OtherComponents
Collapse Residual Drift
Loss Contributions by Component Type for a 50 Year Ground Motion
Output Examples: Repair Cost
8-story concrete frame in Los Angeles
Loss Ratio = 0.04
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Output Examples: Repair Cost
8-story concrete frame in Los Angeles
37%32%
7%1% 1% 2% 1%
19%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
StructuralComponents
Partitions InteriorFinishes
Cladding Plumbing andHVAC
OtherComponents
Collapse Residual Drift
Loss Contributions by Component Type for a 475 Year Ground Motion
Loss Ratio = 0.15
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Output Examples: Repair Cost
8-story concrete frame in Los Angeles
26%
12%
2% 2% 0% 1% 3%
54%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
StructuralComponents
Partitions InteriorFinishes
Cladding Plumbing andHVAC
OtherComponents
Collapse Residual Drift
Loss Contributions by Component Type for a 2475 Year Ground Motion
Loss Ratio = 0.44
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Output Examples: Repair Times
Average Repair Times (REDi, 2013):
0.8 0.9
3.5
0
2
4
6
8
10
12
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REDi Re-Occupancy REDi Functional Recovery REDi Full Recovery
MO
NTH
S
Repair Time Output at a 43 Year Earthquake
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Output Examples: Repair Times
Average Repair Times (REDi, 2013):
6.0 6.3
9.2
0
2
4
6
8
10
12
14
REDi Re-Occupancy REDi Functional Recovery REDi Full Recovery
MO
NTH
S
Repair Time Output at a 475 Year Earthquake
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Output Examples: Repair Times
Average Repair Times (REDi, 2013):
10.7 11.0
13.1
0
2
4
6
8
10
12
14
REDi Re-Occupancy REDi Functional Recovery REDi Full Recovery
MO
NTH
S
Repair Time Output at a 2475 Year Earthquake
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Output Examples: Fatalities and Injuries
Safety (fatalities and injuries):
0.20.0 0.0 0.0
0.20.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Injuries (FromFalling Hazards)
Fatalities (FromFalling Hazards)
Injuries (FromCollapse)
Fatalities (FromCollapse)
Total Injuries Total Fatalities
Mean Casualties at a 43 Year Earthquake
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Output Examples: Fatalities and Injuries
Safety (fatalities and injuries):
1.3
0.0 0.0 0.0
1.3
0.00.0
0.5
1.0
1.5
2.0
2.5
3.0
Injuries (FromFalling Hazards)
Fatalities (FromFalling Hazards)
Injuries (FromCollapse)
Fatalities (FromCollapse)
Total Injuries Total Fatalities
Mean Casualties at a 475 Year Earthquake
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Output Examples: Fatalities and Injuries
Safety (fatalities and injuries):
2.5
0.00.1
0.8
2.6
0.8
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Injuries (FromFalling Hazards)
Fatalities (FromFalling Hazards)
Injuries (FromCollapse)
Fatalities (FromCollapse)
Total Injuries Total Fatalities
Mean Casualties at a 2475 Year Earthquake
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FEMA P-58 provides the comprehensive and standardizedbuilding-specific risk assessment.
SP3 software provides a user-friendly software to integrate all steps in a
FEMA P-58 risk assessment (initially released in 2014).
The initial assessment should take a couple hours and not days or weeks.
Enabling SP3 Commercial Software
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Enabling SP3 Commercial Software
The Goal: Enable widespread and mainstream use of FEMA P-58 for building-specific seismic risk assessment.
The Intended Outcome: We believe that this better understanding of risk will:
(a) facilitate design of more resilient buildings and
(b) enable better decision-making for both mortgage risk and insurance risk.
The Strategy: Provide a software that enables these assessments at a rapid pace, so it’s feasible to use for nearly all projects (taking hours, not days or weeks).
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SP3-Design
Site Hazard Structural Responses
Structural Components &
Fragilities
Nonstructural Components &
Fragilities FEMA P-58 Monte Carlo Analysis
ENGINE
Building-Specific Vulnerability Curves
Repa
ir Co
sts
Ground Shaking
Repa
ir Ti
me
Ground Shaking
Detailed Building and Site
Information
(e.g. structural system and layout,
non-structural components, etc.)
SP3-Design
Licensed Engineer: In the SP3_Engineering tool, inputs are done by a licensed engineer on a
building-specific and site-specific basis (with some
provided automation).
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We released SP3-Design in 2014, with the primary focus on structural engineering designers (new design and retrofit). We have been excited to see SP3-Design used on a wide range of
exciting projects by 85+% of large west coast structural engineering firms, such as:
– Resilient design of new buildings (municipal buildings, court houses, etc.)
– Retrofit of existing buildings– Assessments of special facilities (EOCs, manufacturing, museums, etc.)– Mortgage risk assessments – Investment risk assessments – Insurance risk assessments
FEMA P-58 and SP3 Use-Cases
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Site Hazard Structural Responses
Structural Components &
Fragilities
Nonstructural Components &
Fragilities FEMA P-58 Monte Carlo Analysis
ENGINE
SP3-RiskModel
Basic Building and Site
Information(structural system, number of stories,
location, construction year)
Additional Secondary Modifiers(drift limit,
importance factor, strength,
period, configuration irregularities,
etc.)
SP3 Building-Specific Risk Model
Building-Specific Vulnerability Curves
Full distributions of losses and repair
times, and expected annual values.
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Site Hazard Structural Responses
Structural Components &
Fragilities
Nonstructural Components &
Fragilities FEMA P-58 Monte Carlo Analysis
ENGINE
SP3-RiskModel
Basic Building and Site
Information
Additional Secondary Modifiers(drift limit,
importance factor, strength,
period, configuration irregularities,
etc.)
SP3 BUILDING-SPECIFIC RISK MODEL
Full FEMA P-58 engineering-based risk assessment framework
Automation through many research-backed analytical SP3 Engines and SP3 Databases
(Building Code Database, Archetype Design Database, Structural Response Engine, etc.)
When full automation is used, this provides building-specific and site-specific vulnerability
curves quickly and can be used for large inventories (with support from SP3-Batch)
Building-Specific Vulnerability Curves
Full distributions of losses and repair
times, and expected annual values.
(structural system, number of stories,
location, construction year)
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Motivation – What we get from code-based design, and current pushes for “functional recovery” design FEMA P-58 analysis methods for assessing resilience
(losses and downtime) Research to enable accurate FEMA P-58 analysis for
BRBF buildings Approaches to resilient design of BRBF buildings Summary and Q&A
Agenda for Today
45
© HB Risk Group
Site Hazard Structural Responses
Structural Components &
Fragilities
Nonstructural Components &
Fragilities
Building-Specific Vulnerability Curves
Full distributions of losses and repair
times, and expected annual values.
FEMA P-58 Monte Carlo Analysis
ENGINE
Research Needed for FEMA P-58 for BRBFs
SP3 Structural Response Prediction ENGINE
“We do the nonlinear dynamic structural analysis for you.”
Component Fragility Database
(132 new fragilities specific to brace geometry and higher
ductility of CoreBrace BRBF data)
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Structural Responses
SP3 Structural Response Prediction ENGINE
“We do the nonlinear dynamic structural analysis for you.”
Specifically predict:– peak interstory drift– peak floor acceleration– residual interstory drift (a big focus)
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Overview of Structural Modeling
• Designs from ATC-76 (NIST GCR 10-917-8) – 37 building design archetypes, with 19 in SDC Dmax
– 4 bracing configurations– Used NIST Guidelines for Nonlinear Structural Analysis for
Design of Buildings for the nonlinear modeling (ATC 114)• Three primary model variants
– No gravity system (just the braces)– With gravity system– With backup frame (not designed as dual system)
• OpenSees used for modeling (with 44 ATC-63 ground motions)
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Overview of Structural Modeling
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0 2.5 5 7.5 10 12.5 15
Median Peak IDR / Yield IDR
0
2
4
6
8
10
12
Med
ian
Res
idua
l ID
R /
Yiel
d ID
R
FEMA P-58-1 eqn. 5-24
No Backup Frame
No Backup Frame With Gravity
With Backup Frame
0 0.5 1 1.5 2 2.5 3
Median IDR (%) for y = 0.2%
0
0.4
0.8
1.2
1.6
2
2.4
Med
ian
Res
idua
l ID
R (%
) for
y =
0.2
%
Modeling Results – Residual Drifts
Detailed nonlinear dynamic structural modeling, with many building designs, was
used to refine the residual drift model for CoreBrace BRBF buildings.
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Modeling Results – Residual Drifts
0 2.5 5 7.5 10 12.5 15
Median Peak IDR / Yield IDR
0
2
4
6
8
10
12
Med
ian
Res
idua
l ID
R /
Yiel
d ID
R
FEMA P-58-1 eqn. 5-24
No Backup Frame
No Backup Frame With Gravity
With Backup Frame
0 0.5 1 1.5 2 2.5 3
Median IDR (%) for y = 0.2%
0
0.4
0.8
1.2
1.6
2
2.4
Med
ian
Res
idua
l ID
R (%
) for
y =
0.2
%
The FEMA P-58 default residual drift model is slightly conservative for CoreBrace
BRBFs (but only slightly).
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0 2.5 5 7.5 10 12.5 15
Median Peak IDR / Yield IDR
0
2
4
6
8
10
12
Med
ian
Res
idua
l ID
R /
Yiel
d ID
R
FEMA P-58-1 eqn. 5-24
No Backup Frame
No Backup Frame With Gravity
With Backup Frame
0 0.5 1 1.5 2 2.5 3
Median IDR (%) for y = 0.2%
0
0.4
0.8
1.2
1.6
2
2.4
Med
ian
Res
idua
l ID
R (%
) for
y =
0.2
%
Modeling Results – Residual Drifts
Including a typical gravity system (beam/slab and shear tab connections) substantially reduces
residual drifts.
The FEMA P-58 default residual drift model is slightly conservative for CoreBrace
BRBFs (but only slightly).
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0 2.5 5 7.5 10 12.5 15
Median Peak IDR / Yield IDR
0
2
4
6
8
10
12
Med
ian
Res
idua
l ID
R /
Yiel
d ID
R
FEMA P-58-1 eqn. 5-24
No Backup Frame
No Backup Frame With Gravity
With Backup Frame
0 0.5 1 1.5 2 2.5 3
Median IDR (%) for y = 0.2%
0
0.4
0.8
1.2
1.6
2
2.4
Med
ian
Res
idua
l ID
R (%
) for
y =
0.2
%
Modeling Results – Residual Drifts
The FEMA P-58 default residual drift model is slightly conservative for CoreBrace
BRBFs (but only slightly).
Including a typical gravity system (beam/slab and shear tab connections) substantially reduces
residual drifts.
Including a moment-connected back-up frame in the nonlinear structural
model shows even more reduction in residual drifts.
The typically designed back-up frames (sized for
gravity) were sufficient and they did not need
additional requirements for the back-up frames.
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Component Fragility Functions
Component Fragility Database
(132 new fragilities specific to brace geometry and higher
ductility of CoreBrace BRBF data)
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CoreBrace Fragilities
• Comparison of new fragilities with standard FEMA P-58 fragilities (where the damage state is fracture of the brace requiring replacement)
FEMA P-58 baseline
CoreBrace
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CoreBrace Fragilities
• Coverage: Standard CoreBrace braces– Brace configuration– Connection detail– Steel core area
14 16 20 14 16 20 14 16 20 14 16 2030 30 30 20 20 20 20 20 20 15 15 15
2.14 1.88 1.50 1.43 1.25 1.00 1.43 1.25 1.00 1.07 0.94 0.75
5Bolted Pinned Welded
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Bolted Pinned
Asc
(in2 )
Single Diagonal
Chevron/VBrace ConfigurationStory Ht, H (ft)
Bay Width, B (ft)Bay/Story Height Ratio
Single Diagonal Chevron/V
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CoreBrace Fragilities
• Coverage: Standard CoreBrace braces– Brace configuration– Connection detail– Steel core area
14 16 20 14 16 20 14 16 20 14 16 2030 30 30 20 20 20 20 20 20 15 15 15
2.14 1.88 1.50 1.43 1.25 1.00 1.43 1.25 1.00 1.07 0.94 0.75
5Bolted Pinned Welded
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10Bolted Pinned Welded
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20Bolted Pinned Welded
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30Bolted Pinned
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Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Asc
(in2 )
Single Diagonal
Chevron/VBrace ConfigurationStory Ht, H (ft)
Bay Width, B (ft)Bay/Story Height Ratio
Bolted
Pinned
Welded
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CoreBrace Fragilities
• Coverage: Standard CoreBrace braces– Brace configuration– Connection detail– Steel core area
14 16 20 14 16 20 14 16 20 14 16 2030 30 30 20 20 20 20 20 20 15 15 15
2.14 1.88 1.50 1.43 1.25 1.00 1.43 1.25 1.00 1.07 0.94 0.75
5Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
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10Bolted Pinned Welded
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Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
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20Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
Bolted Pinned Welded
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Bolted Pinned Welded
Bolted Pinned Welded
30Bolted Pinned
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Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Bolted Pinned
Asc
(in2 )
Single Diagonal
Chevron/VBrace ConfigurationStory Ht, H (ft)
Bay Width, B (ft)Bay/Story Height Ratio
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© HB Risk Group
Sample Mean Losses for an 8 Story BRBF in Long Beach, CA
More detail on BRBF seismic resilience will be presentedon Friday by our CEO Curt Haselton(Friday 10:45-11:45am in Room 261)
Sample Risk Assessment Results
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Modeling Results – Residual Drifts
0 2.5 5 7.5 10 12.5 15
Median Peak IDR / Yield IDR
0
2
4
6
8
10
12
Med
ian
Res
idua
l ID
R /
Yiel
d ID
R
FEMA P-58-1 eqn. 5-24
No Backup Frame
No Backup Frame With Gravity
With Backup Frame
0 0.5 1 1.5 2 2.5 3
Median IDR (%) for y = 0.2%
0
0.4
0.8
1.2
1.6
2
2.4
Med
ian
Res
idua
l ID
R (%
) for
y =
0.2
%
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Sample Results – Mean Loss
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Sample Results – Mean Loss
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Sample Results – Mean Loss
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Sample Results – Mean Loss
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Probability of Demolition for an 8 Story BRBF in Long Beach, CA
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Sample Results - Demolition
66
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Sample Results - Demolition
67
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Sample Results - Demolition
68
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Sample Results - Demolition
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Motivation – What we get from code-based design, and current pushes for “functional recovery” design FEMA P-58 analysis methods for assessing resilience
(losses and downtime) Research to enable accurate FEMA P-58 analysis for
BRBF buildings Approaches to resilient design of BRBF buildings Summary and Q&A
Agenda for Today
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Questions: Can we do better in the design process (and should we)? If we want more resilient design to meet loss and downtime
goals in addition to safety goals, what should we do?
Two overall options:1) Use knobs we already have in the building code (strength,
drift, risk category, etc.)2) Use a direct resilient design approach using FEMA P-58
Resilient Design
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1) Keep brace strains low enough to not have fracture and
not need repair (easy with CoreBrace BRBFs).
2) Control residual drifts through use of a back-up frame or additional strength/stiffness.
3) Possibly reduce design drift to prevent drift-sensitive non-structural damage (same for
any structural system).
4) Prevent acceleration-sensitive non-structural
damage by either strengthening anchorages and/or controlling
floor acceleration demands (easier for BRBFs because PFAs are lower than elastic building).
1)
2)
3)
4)
Resilient Design of BRBF Buildings
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Resilient Design of BRBF Buildings
Report:“Resilient Design Guidelines for CoreBraceBuckling Restrained Brace Frame Buildings”
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Code-based design gives us safe, but disposable buildings FEMA P-58 can be used for site-specific, building-specific
seismic risk assessment A structural response prediction method for CoreBrace
BRBFs is available in SP3 Gravity system and Back-up frames significantly reduce
residual drifts
Structural component fragilities specific to CoreBraceBRBFs are implemented in SP3 Practical guidelines for resilient design of BRBFs are
publically available
Summary and Conclusions
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Closing and Questions
Thank you for your time. Our goal is to support adoption of resilience-based design
and risk assessment, and we welcome feedback and suggestions.
Time for questions!
Tracy Rice (HB-Risk admin): [email protected] Haselton: [email protected], Direct: (530) 514-8980
www.hbrisk.com