Recent Developments, Recent Adoption on Projects, and the...

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Curt B. Haselton, PhD, PEProfessor of Civil Engineering @ CSU, Chico

Co-Founder @ Seismic Performance Prediction Program (SP3)

www.hbrisk.com

Resilience-Based Design & Risk Management using FEMA P-58

Recent Developments, Recent Adoption on Projects, and the Future

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Quick orientation to FEMA P-58 and applications Recent innovative projects being done using this

new FEMA P-58 methodMore detail on the FEMA P-58 methodDesign example Plans for future work and development

Agenda for Tonight

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FEMA P-58 is a probabilistic performance prediction methodology (10+ years in the making, $12M+ invested, development ongoing)

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: Fatalities & injuries

FEMA P-58

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FEMA P-58 Modeling Approach

Ground Motion Hazard

Component DamageEconomic Loss

Casualties

Repair Time

Structural Response

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FEMA P-58 Applications

New design (resilience-based design)

Retrofit

Risk evaluations for mortgage (PML) and insurance

Risk evaluations for specialized buildings

Building ratings

Applications: Code design (safety-only and

prescriptive), performance-based design (typically also safety-only)

ASCE 41 (mostly safety-only, except for if using IO)

Experience and judgement-based approaches, which do not handle much building-specific information (e.g. Hazus, ATC-13, ST-Risk, SeismicCat, etc.).

[same as above]

Ratings are new; can use FEMA P-58 methods or checklist-based)

Contrasting Methods:

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Code Design (ASCE7, etc.) Safety Goal - Yes

“Performance”-Based Design (AB 083, ASCE 41, 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

Design and Assessment Methods

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Recent Innovative Resiliency/Risk Projects

In my book, these are exciting times.

I am excited about what is starting to be

done with FEMA P-58 for resilient design

and enhanced risk assessment.

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New Design: Long Beach Civic Center

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New Design: Long Beach Civic Center

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Retrofit Projects: San Francisco, Sacramento, etc.

Figure: https://en.wikipedia.org/wiki/List_of_tallest_buildings_in_San_Francisco

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Risk Assessments: Property Transaction Due-Diligence

FEMA P-58 can be used for PMLs, but also for much more detailed risk

assessments as well (accounting for the building-specific properties, etc.).

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Risk Assessments: Property Transaction Due-Diligence

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Risk Assessments: Detailed Assessments of High-Value Items

Risk to high-value content.

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Risk Assessments: Detailed Assessments of High-Value Items

Post-earthquake operability of production facilitates.

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Assessments for Innovating Structural Systems

Figures: http://cenews.com/userfiles/image/SE1111_44.jpg

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Figures: http://cenews.com/userfiles/image/SE1111_44.jpg, http://precast.org/wp-content/uploads/2010/09/defying_rubber_band.jpg

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Figures: http://img.archiexpo.com/images_ae/photo-g/55901-3675379.jpg

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Figures: http://img.archiexpo.com/images_ae/photo-g/55901-3675379.jpg

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Building ratings and the U.S. Resiliency Council rating system:• articulates FEMA P-58 results to star ratings (e.g. < 5% cost is 5-star).• is useful to communicate performance simply (and my hope is that it

will lead to a push for more resilient design).• is fully implemented in SP3 (SP3 will compute the rating).


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Building ratings and the REDi Rating System (also implemented in SP3):


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FEMA P-58: More Details Under the Hood

Ground Motion Hazard

Component DamageEconomic Loss

Casualties

Repair Time

Structural Response

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FEMA P-58: Ground Motions

Step 1: Define ground motion hazard curve (with soil type)• Option #1: SP3 can provide for the U.S. (given an address)• Option #2: User-specified

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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 and

coupling beam rotations

Option #1: Structural analysis

Option #2: Statistically calibrated predictive equations

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FEMA P-58: Component Damage

Step 3: Quantify component damageFirst, establish what components are in the building. Types and quantities of 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


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


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 $26,892Partitions $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 several thousand 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.


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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 • Fragility curves

Step 4: Loss Estimation (loss curves) and other consequences


Thousands of Monte Carlo simulations

The simulations provide detailed statistical

information on building performance.

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FEMA P-58: Benefits

Standardized component fragilities and costs “Engineering-oriented” approach compliments actuarial

approaches Facilitates building-specific evaluations Provides detailed outputs of repair cost sources, etc.

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FEMA P-58: Summary




Step 4: Loss Estimation (loss curves) and other consequences

Typical Reactions:

Looks extremely complicated!!!

Great method, but it’s a Cadillac and I

would only use it for special projects!!!

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The SP3 Software

A barrier to widespread FEMA P-58 adoption has been related to software and ease-of-use. FEMA P-58 is a great methodology but FEMA is expressly not in the

business of maintaining software. Software has been barrier to adoption. Need: To better enable use of FEMA P-58, a commercial-grade software is

needed. In 2014, Jack Baker and Curt Haselton decide to fill the software need by:

a) Creating user-friendly software to implement P-58. [released Dec. 2014] b) Maintaining software over time (fragilities, etc.). [e.g. working on some

expansions to fragility library now]c) Improving and extending the methodology in the future. [e.g. advanced

repair time estimates, enhanced method for structure responses, etc.]

ATC Coordination: We have been in coordination with ATC/FEMA from the start (so all pulling in same direction).

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The SP3 Software




Step 4: Loss Estimation

USGS Soil and ground motion database

information embedded

Statistically calibrated structural response

methods are embedded

Building contents are auto-populated (using FEMA P-58 and enhanced options)

Structure: Cloud-based computational platform, flexible reporting options

Two-level structure: 1) Use initial pre-populated values2) Modify inputs and dig deeper

We implement the FEMA P-58 calculations, plus a

number of other features.

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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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37%32%

7%1% 1% 2% 1%

19%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%




OtherComponents



Loss Ratio = 0.15

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26%

12%

2% 2% 0% 1% 3%

54%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%




OtherComponents



Loss Ratio = 0.44

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FEMA P-58: Output Examples

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Average Repair Times (REDi, 2013):

0.8 0.9

3.5

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 43 Year Earthquake

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6.0 6.3

9.2

0

2

4

6

8

10

12

14


MO

NTH

S


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10.7 11.0

13.1

0

2

4

6

8

10

12

14


MO

NTH

S


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Average Repair Times (Figure Source: REDi, 2013):

10.7 11.0

13.1

0

2

4

6

8

10

12

14


MO

NTH

S


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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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• Project: Long Beach Civic Center• Building: Design a 11-story RC Wall (coupled core), office occupancy • Site: LA high-seismic, SDS = 1.1g, SD1 = 0.6g.• Design Objectives: Five-star performance in all categories

– Repair Cost < 5%– Functional Recovery Time < 5 days– Safety – high (low collapse, no/few injuries, good egress)

• Showing example for design, but also applicable to assessment.

Quick Design Example

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• Step #1: Start with code-compliant design to see where that gets us...

– Repair Cost = 8% [4-star]– Recovery Time = 6.5 months [3-star]

• 3.0 months – mechanical and electrical (HVAC, lighting, switchgear)

• 2.0 months – structural (mostly walls)• 1.5 months – non-structural drift-sensitive

(partitions, stairs, piping, fire sprinklers)– Safety [3-star]

(discussed at the end)


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• Step #2: Design wall to be “essentially elastic” (very strong)• Step #3: Design mechanical and electrical components to be

functional at the 10% in 50 year (anchorage, equipment, lighting, etc.).

• Result: – Repair Cost = 5.5% [still 4-star]– Recovery Time = 2.5 months [still 3-star]

• 1.0 month – slab-column connections• 1.5 months – partition walls


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• Step #4: Reduce the shear on the slab-column connections.• Step #5: Use less damageable partition walls.

• Result: – Repair Cost = 3.5% [now a 5-star]– Recovery Time = 6 weeks [still a 3-star]

• 3 weeks – slab-column connections• 3 weeks – partition walls


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• Step #6: Stiffen the building (longer walls, more coupling, etc.). Reduces the maximum drifts from around 1.4% to 1.0%.

• Result: – Repair Cost = 2% [5-star]– Recovery Time = 2 days [moved from

3-star to 5-star]

• Step #7: Now that building has less drift, move back to higher shear slab-column connections.

• Result: – Repair Cost = Still 2% [still a 5-star]– Recovery Time = Still 2 days [still a 5-star]


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• Step #8: Now that building has less drift, see if we can move back more damageable partition walls.

• Result: – Repair Cost = 2.5% [5-star]– Recovery Time = 2 weeks [would

moved down to 4-star]

**Move back to less damageable partition walls to keep a 5-star recovery time.


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• Step #9: Safety checks

• Overview of safety checks:– Fatalities. Show good collapse safety (limit fatalities).– Injuries. Check injury prediction from FEMA P-58 (would require

additional non-structural bracing to get to 5-star). – Residual Drifts. Very low (essentially elastic).– Stairs and Egress. Check probability of non-functionality

(direct outputs from the FEMA P-58 detailed results).


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• Final Design Outcomes:– Repair Cost: 2% [5-star]– Functional Recovery Time: 2 days [5-star]– Safety: Low fatality+injury risk and good egress) [5-star]

• This example was for new design, but FEMA P-58 offers this same level of building-specific detail when doing performance assessments as well.


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The FEMA P-58 method and SP3 are complete and ready for use. Even so, we are continuing further development to:

• Make the methods cover all structural systems and conditions (already covers nearly all of them).

• Streamline the analysis methods to make the analysis quicker.

Future Develop. in Resiliency/Risk Assessment

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Streamline analysis with the enhanced Statistical Response Method (to estimate structural responses without a complete structural model)


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Questions and Discussion

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 and discussion!

Curt Haselton: [email protected], (530) 514-8980 Jack Baker: [email protected]

www.hbrisk.com

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