Rapid Visual Screening of Buildings for Potential

Seismic Vulnerability Fred Krimgold

Virginia Tech

CDM5 December 7, 2010

Documents

FEMA 154 Table of Contents

1.1. IntroductionIntroduction

2.2. Planning and Managing Rapid Planning and Managing Rapid Visual Screening (RVS)Visual Screening (RVS)

3.3. Completing the Data Collection Completing the Data Collection FormForm

4.4. Using the RVS Procedure ResultsUsing the RVS Procedure Results

5.5. Example Application of Rapid Example Application of Rapid Visual ScreeningVisual Screening

6.6. AppendicesAppendices

Key Questions

City Vulnerability AssessmentCity Vulnerability Assessment What is our building stock?What is our building stock? What is the risk for occupants?What is the risk for occupants? What is the risk to property and What is the risk to property and business?business?

How can this risk be managed and reduced?How can this risk be managed and reduced? What happens to the city if we do What happens to the city if we do nothing?nothing?

Outline of Presentation

Description of ProcedureDescription of Procedure Behavior of BuildingsBehavior of Buildings Building Types and Typical DamageBuilding Types and Typical Damage Basic Scores and Score ModifiersBasic Scores and Score Modifiers Occupancy and Falling HazardsOccupancy and Falling Hazards Implementation of ProcedureImplementation of Procedure Example ApplicationsExample Applications

Purpose and Limitations of Procedure

PurposePurpose Screen for potential seismic hazardsScreen for potential seismic hazards Identify buildings that may be hazardousIdentify buildings that may be hazardous

LimitationsLimitations Some hazardous buildings might not be Some hazardous buildings might not be identifiedidentified

Some adequate buildings might be identified Some adequate buildings might be identified as hazardousas hazardous

Accurate results dependent on experience of Accurate results dependent on experience of screener and thoroughness of pre-field screener and thoroughness of pre-field activitiesactivities

Seismic Hazard Map

High

Moderate

Low

Seismicity Region Definition

Region of Seismicity

Spectral Acceleration (short period or 0.2 sec)

Spectral Acceleration

(long period or 1.0 sec)

Low < 0.167 g < 0.067 g

Moderate ≤ 0.167 g < 0.50 g

≤ 0.067 g < 0.2 g

High ≤ 0.50 g ≤ 0.20 g

Data Collection FormSeismicity

Building Type

Basic Score

ScoreModifiersFinal Score

Evaluation

Building Types

Building MaterialsBuilding Materials WoodWood SteelSteel ConcreteConcrete MasonryMasonry

Lateral Force Resisting SystemLateral Force Resisting System Shear WallShear Wall Moment FrameMoment Frame Braced FrameBraced Frame

Score Modifiers

HeightHeight Mid rise (4-7 stories)Mid rise (4-7 stories) High rise (>7 stories)High rise (>7 stories)

Vertical irregularityVertical irregularity Plan irregularityPlan irregularity Pre-codePre-code Post benchmarkPost benchmark Soil typeSoil type

Structural Scores and Modifiers

Building Type

Score Modifiers

Basic Score

Final Score Calculation

2.8

Basic Score 4.8

Mid Rise +0.4

VerticalIrregularity -2.0

Soil Type C -0.4

Final Score 2.8

Seismic Hazards and Performance Levels

Seismic HazardsSeismic Hazards Probabilistic (Return period or Probabilistic (Return period or probability of exceedence)probability of exceedence)

DeterministicDeterministic Seismic Performance LevelsSeismic Performance Levels

Collapse PreventionCollapse Prevention Life SafetyLife Safety Immediate OccupancyImmediate Occupancy OperationalOperational

Data Collection Form Building Types

WoodWood Light wood frame (W1)Light wood frame (W1) Large wood frame (W2)Large wood frame (W2)

SteelSteel Steel moment frame (S1)Steel moment frame (S1) Steel braced frame (S2)Steel braced frame (S2) Light metal building (S3)Light metal building (S3) Steel frame with concrete shear walls Steel frame with concrete shear walls (S4)(S4)

Steel frame with URM infill (S5)Steel frame with URM infill (S5)

Data Collection Form Building Types

ConcreteConcrete Concrete moment frame (C1)Concrete moment frame (C1) Concrete shear wall (C2)Concrete shear wall (C2) Concrete frame with URM infill (C3)Concrete frame with URM infill (C3) Tilt-up concrete (PC1)Tilt-up concrete (PC1) Precast concrete frame (PC2)Precast concrete frame (PC2)

MasonryMasonry Reinforced masonry with flexible diaphragm Reinforced masonry with flexible diaphragm (RM1)(RM1)

Reinforced masonry with rigid diaphragm (RM2)Reinforced masonry with rigid diaphragm (RM2) Unreinforced masonry (URM)Unreinforced masonry (URM)

Steel Moment Frame (S1)

Girder or Beam

ColumnSlab

Welded MomentConnection

Welded or BoltedShear Connection

S1 Example

Crack weld at bottom flange of the girder to

column flange moment connection

S1 Performance

S2 Performance

Tube Steel Brace Fractured Due to

Buckling

S4 Performance

Cracked Concrete Wall at Interior Elevator Core

Steel Frame with URM Infill (S5)

Wood Framing

Steel Frame

3-WytheBrick Infill Wall

Ledger forExterior Wythe

S5 Example

S5 Performance

Concrete Moment Frame (C1)

Infill Wall

Curtain wall

C1 Example

C1 Performance

Shear Cracks in Columns

Concrete Shear Wall (C2)

C2 Example

C2 Performance

Shear and Bending Cracks in Shear WallsRepaired by Epoxy Injection

Concrete Frame with URM Infill (C3)

Concrete Frame

Brick Infill

C3 Example

C3 Performance

X-Cracks in Infill Panels

Tilt-up Concrete (PC1)

PC1 Performance

PC2 Performance

Precast Connections Failed

Undamaged Shear Wall

Unreinforced Masonry (URM)

URM Bearing Walls

Header Course

URM Example

URM Performance

Out-of-Plane Wall Failure

Multiple or Unknown Building Types

ProcedureProcedure Eliminate building typesEliminate building types Use interior inspection and Use interior inspection and drawing review, if possibledrawing review, if possible

Evaluate all probable building Evaluate all probable building typestypes

Record lowest scoreRecord lowest score

Recording Building Type

and ScoreSeismicity

Building Type

IdentifierAbbreviationBasic Score

W2 S1(MRF)

S2(BR)

3.8 2.8 3.0

Basic Structural Hazard Scores

BuildingType

LowSeismicity

ModerateSeismicity

HighSeismicity

W1 S1 S3 PC1 URM

7.4 4.6 4.6 4.4 4.6

5.2 3.6 3.8 3.2 3.4

4.4 2.8 3.2 2.6 1.8

Score Modifiers

Mid Rise (4-7 Stories)High Rise (>7 Stories)Vertical IrregularityPlan IrregularityPre-CodePost BenchmarkSoil Type CSoil Type DSoil Type E

Vertical Irregularity

SetbacksSetbacks HillsideHillside Soft StorySoft Story Short ColumnShort Column

Setbacks Hillside

Soft StoryShort Column

Setback Example

Soft Story Example

Short Columns Example

Plan Irregularity

L-Shaped T-Shaped U-Shaped

Large Opening Weak Link Between Larger Building Plan Areas

L-Shaped T-Shaped U-Shaped

Large OpeningWeak Link Between Larger Building Plan Areas

Plan Irregularity Example

Pre-Code

Constructed prior to initial Constructed prior to initial adoption and enforcement of adoption and enforcement of seismic codesseismic codes

Applies to Moderate and High Applies to Moderate and High seismic zonesseismic zones

Default year is 1941 Default year is 1941 (California)(California)

Post Benchmark Years

Note: BD - Contact Local Building Department

BuildingType

W1

W2

S1

S2

S3 / S5

S4

BOCA SBCC UBC

1992 1993 1976

1992 1993 1976

BD BD 1994

1992 1993 1988

None None None

1992 1993 1976

Post Benchmark (Cont.)Building

Type

C1 / C2

C3

PC1 / RM1

PC2

RM2

URM

BOCA SBCC UBC

1992 1993 1976

None None None

None None 1997

None None None

None None 1991

1992 1993 1976

Soil Type

Type A - hard rockType A - hard rock Type B - rockType B - rock Type C - Soft rock and very Type C - Soft rock and very dense soildense soil

Type D - Stiff soilType D - Stiff soil Type E - Soft soilType E - Soft soil Type F - Poor soilType F - Poor soil

Soil Type Map

Occupancy AssemblyAssembly CommercialCommercial Emergency Emergency ServicesServices

GovernmentGovernment HistoricHistoric IndustrialIndustrial OfficeOffice ResidentialResidential SchoolSchool

Number of Number of OccupantsOccupants

0 - 100 - 10 11 - 10011 - 100 101 - 1000101 - 1000 >1000>1000

Nonstructural Falling Hazards

Unreinforced ChimneysUnreinforced Chimneys ParapetsParapets Cladding or veneerCladding or veneer OtherOther

AppendagesAppendages EquipmentEquipment

Performance of Parapets

Performance of Cladding

Other Falling Hazards

ArchitecturalArchitectural Interior ornamentationInterior ornamentation Heavy partitionsHeavy partitions

Building servicesBuilding services Mechanical equipmentMechanical equipment Electrical equipmentElectrical equipment

ContentsContents Racks and shelvingRacks and shelving

Rapid Visual Screening Implementation

Plan field survey and identify the area to be screened

Acquire and reviewpre-field data

Develop budget and cost estimate

Choose and train screeners

Select and reviewData Collection Form

Review existing construction drawings

Check the field data in the record keeping system

Photograph the building

If you have access to the interior, verify building type and

irregularities

Screen the building, sketch the plan and

elevation

Pre-Screening Tasks

Determine seismicity regionDetermine seismicity region Determine key seismic code Determine key seismic code adoption datesadoption dates

Determine cut-off scoreDetermine cut-off score Acquire pre-field survey Acquire pre-field survey building databuilding data

Determine soil informationDetermine soil information

Field Survey Tools Binoculars for high-rise buildingsBinoculars for high-rise buildings Camera, preferably instant or digitalCamera, preferably instant or digital Clipboard for holding Data Collection Clipboard for holding Data Collection FormsForms

Copy of the FEMA 154 Copy of the FEMA 154 HandbookHandbook The Quick Reference GuideThe Quick Reference Guide Pen or pencilPen or pencil Straight edge (optional for drawing Straight edge (optional for drawing sketches)sketches)

Tape or stapler, for affixing instant Tape or stapler, for affixing instant photos photos

Data Collection Form Building Building IdentificationIdentification

Sketch Sketch PhotographPhotograph Falling Falling HazardsHazards

Soil TypeSoil Type OccupancyOccupancy Building TypeBuilding Type ModifiersModifiers Final ScoreFinal Score CommentsComments Evaluation Evaluation RequiredRequired

Use of RVS Results Designing seismic hazard mitigation programs Designing seismic hazard mitigation programs Ranking seismic rehabilitation needs Ranking seismic rehabilitation needs Developing building inventoriesDeveloping building inventories

Earthquake damage and loss impact assessmentsEarthquake damage and loss impact assessments Planning post-earthquake building safety Planning post-earthquake building safety evaluationsevaluations

Developing seismic vulnerability information Developing seismic vulnerability information Insurance rating Insurance rating Building ownership transfersBuilding ownership transfers Triggering seismic rehabilitation requirements Triggering seismic rehabilitation requirements during building remodel permittingduring building remodel permitting

Example 1

Example 1 (Cont.)

Building Type:ConcreteShear WallC2

Example 1 (Cont.)

Modifiers:Mid RiseVertical IrregularityPlan IrregularitySoil Type D

Example 1 Scoring

1.2

Building Type C2

Basic Score 2.8

Mid Rise 0.4

Vertical Irreg -1.0

Plan Irreg -0.5

Soil Type D -0.5

Final Score 1.2

Example 1 - Completed Form

Office

4Oakland, CA

1.2

Plan

High Roof4 Stories

4th FloorAddition

4 Stories

4 Stories

3 Stories

FEMA Existing Buildings Program

ASCE 31 (FEMA 310) – Seismic EvaluationASCE 31 (FEMA 310) – Seismic Evaluation ASCE 41 (FEMA 356) – Seismic Rehab ASCE 41 (FEMA 356) – Seismic Rehab GuidelinesGuidelines

FEMA 395-400 – Incremental Seismic FEMA 395-400 – Incremental Seismic Rehabilitation of Various OccupanciesRehabilitation of Various Occupancies

FEMA 420 – Engineers Guide to FEMA 420 – Engineers Guide to Incremental Seismic RehabilitationIncremental Seismic Rehabilitation

FEMA 547 – Techniques for Seismic FEMA 547 – Techniques for Seismic Strengthening of BuildingsStrengthening of Buildings