Flood Resistant Design CodeMaster Webinar May 14, 2014

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1 Flood Resistant Design CodeMaster Webinar May 14, 2014 Christopher P. Jones, P.E.

2 CodeMaster Series CodeMaster: A laminated quick guide to assist users in understanding and applying building code requirements related to a particular hazard or topic: Wind Design Overview IBC Seismic Design Flood Resistant Design etc. Identifies a step-by-step procedure for applying building code provisions 2

3 CodeMaster Series CodeMaster: Often co-branded by other organizations Flood Resistant Design CodeMaster was developed by FEMA and S.K. Ghosh Associates, Structures & Codes Institute SCI Published by (SCI): Also available at: 3

4 Flood Resistant Design CodeMaster Unlike other CodeMasters, the Flood Resistant Design CM is tied to multiple code editions (IRC and IBC: 2009, 2012, earlier editions) Reference ASCE (Flood Resistant Design and Construction), and ASCE 7-05 and 7-10 (Minimum Design Loads for Buildings and Other Structures) First 8-page CodeMaster 4

5 Flood Resistant Design CodeMaster Introductory Material How the pieces fit together: NFIP regulations Community flood regulations Building codes and standards 5

6 Secrets of the CodeMaster Information and explanations not readily known by designers Inserted in yellow boxes throughout 6

7 Flood CM Step Procedure Preliminary Considerations 7

8 Preliminary Considerations - Terminology CodeMaster includes a Flood Terminology section, with over 30 terms included (defined terms are in bold italics throughout CM) Definitions are a combination of code and NFIP definitions Code references are provided for each definition 8

9 Flood CM Step Procedure Steps 1-2: determine if flood provisions apply and which code governs 9

10 Step 1: FHA? 1. Does the structure lie, in whole or in part, in the Flood Hazard Area? 10

11 Step 2: Governing Code? 2. Determine which Code Governs, IRC or IBC 11

12 IBC ASCE-24 Contains prescriptive and performance flood-resistant design and construction requirements First edition in 1998, second in 2005; 2014 edition in progress IBC (2006, 2009, 2012) requires compliance with ASCE IRC allows*, but does not require, use of ASCE 24 * if in floodway, IRC requires use of ASCE 24 12

13 ASCE-24 References ASCE-7 for flood loads Requires freeboard; treats CAZ like zone V Chapter 3 deals with High Risk Flood Hazard Areas: Alluvial fan Flash flood Mudslide Erosion-prone High velocity flow Ice jam and debris Wave action (go to Chapter 4) 13

14 Flood CM Step Procedure Steps 1-2: determine if flood provisions apply and which code governs IRC: steps 3-7 are required; steps 9-12 can inform IRC users 14

15 12-Step Procedure: IRC Use Steps Determine Flood Hazard Zone 4. Determine Design Flood Elevation (DFE) 5. Determine Minimum Elevation of Lowest Floor 6. Determine Permissible Foundation Types 7. Determine and Apply IRC Flood Provisions 15

16 Flood CM Step Procedure Steps 1-2: determine if flood provisions apply and which code governs IRC: steps 3-7 are required; steps 9-12 can inform IRC users IBC: steps 3-6, 8-12 are required 16

17 IBC Uses Steps 3-6, 8-12* 8. Determine and Apply IBC Flood Provisions 9. Determine Design Flood Conditions 10.Calculate Design Flood Loads 11.Determine Flood Load F a for Load Combinations 12.Design the Foundation * IRC users should review steps

18 Flood CM Step Procedure Steps 1-2: determine if flood provisions apply and which code governs IRC: steps 3-7 are required; steps 9-12 can inform IRC users IBC: steps 3-6, 8-12 are required Coastal: as above Riverine: as above; omit steps 9.6 (estimate coastal wave height) and 10.4 (calculate coastal wave load) 18

19 Step 3: Flood Hazard Zone(s)? 3. Determine Flood Hazard Zone(s) 19

20 SFHA Flood Zones A Zones V Zones 3-ft breaking wave 3-ft runup depth Wave overtopping } Shown on the FIRM Coastal A Zones ft breaking wave Used in ASCE 7, 24, not shown on FIRM. LiMWA is shown.) 20

21 Coastal FIRM with LiMWA (establishes CAZ) Limit of Moderate Wave Action 21

22 Floodway 2012 IRC directs you to ASCE IRC sent you to IBC, which sent you to ASCE 24 surcharge* Allowable surcharge will be 1.0 ft at most. Check with AHJ. Some jurisdictions permit no rise. 22

23 Step 4: DFE 4. Determine Design Flood Elevation (DFE) 23

24 Step 5: Lowest Floor Elevation 5. Determine Minimum Elevation of Lowest Floor 24

25 Step 6: Permissible Foundations 6. Determine Permissible Foundation Types 25

26 Step 6: Permissible Foundations 6. Determine Permissible Foundation Types 26

27 IRC Uses Step 7 7. Determine and Apply Applicable IRC Provisions Topic Basic Flood Resistance R322.1 Flood Loads and Conditions Lowest Floor Elevation Foundation IRC Section R301.1, Table R301.2(1), R , R R309.3, R , R R , R , R401 Use of Fill R , R (3) and (4), R401.2, R Basements Use of Enclosed Areas below DFE R , R R309.3, R , R

28 IRC Uses Step 7 7. Determine and Apply Applicable IRC Provisions Topic Flood Openings in Below-DFE Enclosures Breakaway Walls Flood Damage-Resistant Materials Mechanical, Electrical Equipment and Systems, Plumbing, Fuel Gas R , R408.7 IRC Section R , R R R , M , M1401.5, M , M1701.2, M2001.4, M2201.6, G2404.7, P2601.3, P2602.2, P2705.1, P3001.3, P

29 IRC Uses Step 7 7. Determine and Apply Applicable IRC Provisions Topic Dry Floodproofing High Risk Flood Hazard Areas Existing Buildings: Repairs, Renovations, Additions, Substantial Damage and Improvement Historic Buildings Not permitted IRC Section See floodway, V Zone requirements and Coastal A Zone requirements: R , R , R322.1, R , R322.2, R322.3 R , R , R , R , R R

30 IRC Uses Step 7 7. Determine and Apply Applicable IRC Provisions Topic Documentation, Inspections and Certifications (Lowest Floor Elevation, Flood Openings, Dry Floodproofing, Breakaway Walls, V Zone Design) IRC Section R , R , R , R , R , R , R , R , R , 30

31 Step 6: Permissible Foundations Determine Permissible Foundation Types IBC 31

32 Step 6: Permissible Foundations Determine Permissible Foundation Types IBC 32

33 Step 6: Permissible Foundations Determine Permissible Foundation Types IBC 33

34 IBC Uses Step 8 8. Determine and Apply Applicable IBC Provisions Topic IBC Section ASCE-7, ASCE-24 Basic Flood Resistance , ASCE 24-05: 1.5 Flood Loads and Conditions Lowest Floor Elevation , , , ASCE 24-05: 1.6 ASCE 7-05: 2.3.3, 2.4.2, 5.3.1, 5.3.2, , ASCE 24-05: 2.3, 4.4 Foundation , Chapter 18 ASCE 24-05: 1.5.3, 2.5,

35 IBC Uses Step 8 8. Determine and Apply Applicable IBC Provisions Topic IBC Section ASCE-7, ASCE-24 Use of Fill ASCE 24-05: 1.5.4, 2.4, Basements 202, ASCE 24-05: 1.2, 1.5.2, 2.3 Use of Enclosed Areas below DFE Flood Openings in Below-DFE Enclosures see ASCE 24 ASCE 24-05: 2.6, (5) ASCE 24-05: 2.6.1, 2.6.2,

36 IBC Uses Step 8 8. Determine and Apply Applicable IBC Provisions Topic IBC Section ASCE-7, ASCE-24 Breakaway Walls , ASCE 24-05: 1.2, 4.6 Flood Damage- Resistant Materials Mechanical, Electrical Equipment and Systems, Plumbing ASCE 7-05: , , ASCE 24-05: 1.2, , ASCE 24-05: 4.6.1,

37 IBC Uses Step 8 8. Determine and Apply Applicable IBC Provisions Topic IBC Section ASCE-7, ASCE-24 Dry Floodproofing ASCE 24-05: 1.2, 1.5.2, 6.0, 7.1 High Risk Flood see ASCE 24 ASCE 24-05: 3.0, 4.0 Hazard Areas Existing Buildings: Repairs, Renovations, Additions, SD and SI , , , , , ASCE 24-05: 1.1, 1.2,

38 IBC Uses Step 8 8. Determine and Apply Applicable IBC Provisions Topic IBC Section ASCE-7, ASCE-24 Historic Buildings ASCE 24-05: 1.1, 1.2 Documentation, Inspections and Certifications (Lowest Floor Elevation, Flood Openings, Dry Floodproofing, Breakaway Walls, V Zone Design) , , , , , Not applicable 38

39 IBC Uses Steps 9-12* 9. Determine Design Flood Conditions 10. Calculate Design Flood Loads 11. Determine Flood Load F a for Load Combinations 12. Design the Foundation * IRC users should review steps

40 Riverine vs. Coastal Conditions Riverine Flooding: Coastal Flooding: (inundation, duration, velocity, debris) (inundation, waves, velocity, erosion, debris, wind) 40

41 ASCE-7 Since 1995, has contained flood load calculation procedures in Chapter 5 hydrostatic loads hydrodynamic loads (flowing water) breaking waves loads on walls and columns flood-borne debris impact loads (much commentary added in 2002 edition) Load combinations (Chapter 2) 2016 edition will have significant changes to flood load provisions 41

42 Step 9: Design Flood Conditions Design Flood Condition Stillwater Elevation (SWEL) Anticipated Eroded Ground Elevation Stillwater Flood Depth, d s Used For Calculating stillwater flood depth Calculating stillwater flood depth Calculating hydrostatic and hydrodynamic loads, coastal wave heights CodeMaster Notes Step 9.1 Obtain from FIS/FIRM or sitespecific determination 9.2 Some sites will not be subject to erosion during design flood 9.3 Obtain by subtracting anticipated eroded ground elevation from SWEL 42

43 Step 9.1: Determine Stillwater Elevation (SWEL) 43

44 Step 9.2: Account for Erosion and Scour 44

45 Step 9.3: Calculate Design Stillwater Flood Depth 45

46 Step 9: Design Flood Conditions Design Flood Condition Flood Velocity Floodborne Debris Coastal Wave Height Used For Calculating hydrodynamic loads Calculating debris impact loads Calculating breaking wave loads (coastal design only) CodeMaster Notes Step 9.4 Estimated from FIS or sitespecific determination; ASCE 7-05: C ASCE 7-05: C ASCE 7-05:

47 Step 9.4: Estimate Flood Velocity SWEL We often obtain or assume depth-average velocity 47

48 Step 9.5: Characterize Floodborne Debris 48

49 Step 9.6: Estimate Coastal Wave Height 49

50 Step 10: Calculate Design Flood Loads 10.1 Hydrostatic Loads, F sta and F buoy 10.2 Hydrodynamic Load, F dyn 10.3 Floodborne Debris Load, F i 10.4 Coastal Wave Load, F brk 50

51 Step 10.1: Hydrostatic Loads 51

52 Hydrostatic Loads 52

53 Step 10.2: Hydrodynamic Loads 53

54 Hydrodynamic Loads Photo courtesy of 54

55 Step 10.3: Floodborne Debris Impact Loads 55

56 Step 10.4: Wave Loads 56

57 Wave Loads 57

58 Step 11: Determine Flood Load F a for Load Combinations ASCE 7-05 and 7-10 use a single flood load, F a, in equations where flood loads are combined with other loads (dead load, wind load, etc.) Step 11 of the Flood CodeMaster provides guidance on calculating F a, for flood loads, given the hydrostatic, hydrodynamic, wave, and floodborne debris impact loads calculated in Step 10 58

59 Step 12: Design the Foundation Calculate all loads acting on the foundation and elevated structure Assume a preliminary foundation design Check the adequacy of the foundation Check the ability of the foundation to resist applied loads. Check the adequacy of the soils that support the foundation to resist lateral and vertical loads imposed by the foundation Verify that both the foundation and the supporting soils can resist all imposed loads, after accounting for scour and erosion If necessary, revise the foundation design and recalculate loads Final foundation design is achieved when all checks are passed 59

60 Example Problem Given: commercial building in riverine floodplain Example leads the reader through the step-by-step process Applicable Code and SWEL, DFE, flood depth are determined (velocity and erosion are given by Jurisdiction) Flood conditions are determined, flood loads are calculated 60

61 Example Problem -- Solution 61

62 Example Problem 62

63 Final Comments CodeMasters provide step-by-step procedures to help users understand and apply code provisions Flood resistant provisions of building codes are not as well known as wind or seismic The Flood CodeMaster will help users to understand and apply code provisions for buildings in Flood Hazard Areas 63

64 Questions Christopher P. Jones, P.E. Durham, NC 64