Rapid Visual Screening of Buildings for Potential Seismic Vulnerability

1. Rapid Visual Screening of Buildings for Potential Seismic Vulnerability Fred Krimgold Virginia Tech CDM5 December 7, 2010

2. Documents

3. FEMA 154 Table of Contents • Introduction • Planning and Managing Rapid Visual Screening (RVS) • Completing the Data Collection Form • Using the RVS Procedure Results • Example Application of Rapid Visual Screening • Appendices

4. Key Questions • City Vulnerability Assessment • What is our building stock? • What is the risk for occupants? • What is the risk to property and business? • How can this risk be managed and reduced? • What happens to the city if we do nothing?

5. Outline of Presentation • Description of Procedure • Behavior of Buildings • Building Types and Typical Damage • Basic Scores and Score Modifiers • Occupancy and Falling Hazards • Implementation of Procedure • Example Applications

6. Purpose and Limitations of Procedure • Purpose • Screen for potential seismic hazards • Identify buildings that may be hazardous • Limitations • Some hazardous buildings might not be identified • Some adequate buildings might be identified as hazardous • Accurate results dependent on experience of screener and thoroughness of pre-field activities

7. Seismic Hazard Map High Moderate Low

8. Seismicity Region Definition Spectral Spectral Region of Acceleration Acceleration Seismicity (short period (long period or or 0.2 sec) 1.0 sec) Low < 0.167 g < 0.067 g ≤ ≤ 0.167 g 0.067 g Moderate < 0.50 g < 0.2 g ≤ ≤ 0.50 g 0.20 g High

9. Data Collection Form Seismicity Building Type Basic Score Score Modifiers Final Score Evaluation

10. Building Types • Building Materials • Wood • Steel • Concrete • Masonry • Lateral Force Resisting System • Shear Wall • Moment Frame • Braced Frame

11. Score Modifiers • Height • Mid rise (4-7 stories) • High rise (>7 stories) • Vertical irregularity • Plan irregularity • Pre-code • Post benchmark • Soil type

12. Structural Scores and Modifiers Building Type Basic Score Score Modifiers

13. Final Score Calculation Basic Score 4.8 Mid Rise +0.4 VerticalIrregularity -2.0 Soil Type C -0.4 Final Score 2.8 2.8

14. Seismic Hazards and Performance Levels • Seismic Hazards • Probabilistic (Return period or probability of exceedence) • Deterministic • Seismic Performance Levels • Collapse Prevention • Life Safety • Immediate Occupancy • Operational

15. Data Collection Form Building Types • Wood • Light wood frame (W1) • Large wood frame (W2) • Steel • Steel moment frame (S1) • Steel braced frame (S2) • Light metal building (S3) • Steel frame with concrete shear walls (S4) • Steel frame with URM infill (S5)

16. Data Collection Form Building Types • Concrete • Concrete moment frame (C1) • Concrete shear wall (C2) • Concrete frame with URM infill (C3) • Tilt-up concrete (PC1) • Precast concrete frame (PC2) • Masonry • Reinforced masonry with flexible diaphragm (RM1) • Reinforced masonry with rigid diaphragm (RM2) • Unreinforced masonry (URM)

17. Steel Moment Frame (S1) Column Slab Welded or Bolted Shear Connection Girder or Beam Welded Moment Connection

18. S1 Example

19. S1 Performance Crack weld at bottom flange of the girder to column flange moment connection

20. S2 Performance Tube Steel Brace Fractured Due to Buckling

21. S4 Performance Cracked Concrete Wall at Interior Elevator Core

22. Steel Frame with URM Infill (S5) Ledger for Exterior Wythe 3-Wythe Brick Infill Wall Steel Frame Wood Framing

23. S5 Example

24. S5 Performance

25. Concrete Moment Frame (C1) Infill Wall Curtain wall

26. C1 Example

27. C1 Performance Shear Cracks in Columns

28. Concrete Shear Wall (C2)

29. C2 Example

30. C2 Performance Shear and Bending Cracks in Shear Walls Repaired by Epoxy Injection

31. Concrete Frame with URM Infill (C3) Concrete Frame Brick Infill

32. C3 Example

33. C3 Performance X-Cracks in Infill Panels

34. Tilt-up Concrete (PC1)

35. PC1 Performance

36. PC2 Performance Precast Connections Failed Undamaged Shear Wall

37. Unreinforced Masonry (URM)

38. URM Bearing Walls Header Course

39. URM Example

40. URM Performance Out-of-Plane Wall Failure

41. Multiple or Unknown Building Types • Procedure • Eliminate building types • Use interior inspection and drawing review, if possible • Evaluate all probable building types • Record lowest score

42. Recording Building Type and Score Seismicity Building Type Identifier S2(BR) S1(MRF) W2 Abbreviation 2.8 3.0 3.8 Basic Score

43. 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

44. Score Modifiers Mid Rise (4-7 Stories) High Rise (>7 Stories) Vertical Irregularity Plan Irregularity Pre-Code Post Benchmark Soil Type C Soil Type D Soil Type E

45. Vertical Irregularity • Setbacks • Hillside • Soft Story • Short Column Setbacks Hillside Short Column Soft Story

46. Setback Example

47. Soft Story Example

48. Short Columns Example

49. Plan Irregularity L-Shaped T-Shaped U-Shaped Weak Link Between Larger Building Plan Areas Large Opening

50. Plan Irregularity Example