Rapid Visual Screening of Buildings for Potential
Seismic Vulnerability Fred Krimgold
Virginia Tech
CDM5 December 7, 2010
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
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
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
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
Steel Frame with URM Infill (S5)
Wood Framing
Steel Frame
3-WytheBrick Infill Wall
Ledger forExterior Wythe
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
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
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
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
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 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