Flood Resistant Design CodeMaster Webinar€¦ · Flood Resistant Design CodeMaster Webinar May 14, 2014 . 2 ... and ASCE 7-05 and 7-10 ... •Code references are provided for each
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Christopher P. Jones, P.E.
chris.jones@earthlink.net
Flood Resistant Design CodeMaster Webinar
May 14, 2014
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
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): www.skghoshassociates.com
Also available at: http://shop.iccsafe.org/
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 24-05 (Flood
Resistant Design and Construction),
and ASCE 7-05 and 7-10 (Minimum
Design Loads for Buildings and Other
Structures)
• First 8-page CodeMaster
5
Flood Resistant Design CodeMaster
Introductory Material
• How the pieces fit
together:
• NFIP regulations
• Community flood
regulations
• Building codes and
standards
6
“Secrets” of the CodeMaster
• Information and explanations not readily known by designers
• Inserted in yellow boxes throughout
7
Flood CM -- 12-Step Procedure
Preliminary
Considerations
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
9
Flood CM -- 12-Step Procedure
• Steps 1-2: determine if flood
provisions apply and which code
governs
10
Step 1: FHA?
1. Does the structure lie, in whole or in part, in
the Flood Hazard Area?
11
Step 2: Governing Code?
2. Determine which Code Governs, IRC or IBC
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 24-05
• IRC allows*, but does not require, use of ASCE 24
* if in floodway, IRC requires use of ASCE 24
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)
14
Flood CM -- 12-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
15
12-Step Procedure: IRC Use Steps 3-7
3. 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
16
Flood CM -- 12-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
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 Fa for Load Combinations
12.Design the Foundation
* IRC users should review steps 9-12
18
Flood CM -- 12-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)
19
Step 3: Flood Hazard Zone(s)?
3. Determine Flood Hazard Zone(s)
20
SFHA Flood Zones
• A Zones
• V Zones
• Coastal A Zones
Shown on the FIRM }
Used in ASCE 7, 24, not shown on FIRM. LiMWA is shown.)
3-ft breaking wave 3-ft runup depth Wave overtopping
1.5-3 ft breaking wave
21
Coastal FIRM with LiMWA (establishes CAZ)
Limit of Moderate
Wave Action
22
Floodway
surcharge*
2012 IRC directs you to ASCE 24
2009 IRC sent you to IBC, which sent you
to ASCE 24
Allowable surcharge will be
1.0 ft at most. Check with
AHJ. Some jurisdictions
permit no rise.
23
Step 4: DFE
4. Determine Design Flood Elevation (DFE)
24
Step 5: Lowest Floor Elevation
5. Determine Minimum Elevation of Lowest Floor
25
Step 6: Permissible Foundations
6. Determine Permissible Foundation Types
26
Step 6: Permissible Foundations
6. Determine Permissible Foundation Types
27
IRC Uses Step 7
7. Determine and Apply Applicable IRC Provisions
Topic IRC Section
Basic Flood Resistance R322.1
Flood Loads and Conditions R301.1, Table R301.2(1),
R322.1.2, R322.3.3
Lowest Floor Elevation R309.3, R322.2.1, R322.3.2
Foundation R322.2.3, R322.3.3, R401
Use of Fill R322.1.4.2, R322.3.2(3) and (4),
R401.2, R506.2.1
Basements R322.2.1, R322.3.2
Use of Enclosed Areas below DFE R309.3, R322.2.2, R322.3.5
28
IRC Uses Step 7
7. Determine and Apply Applicable IRC Provisions
Topic IRC Section
Flood Openings in Below-DFE
Enclosures
R322.2.2, R408.7
Breakaway Walls R322.1.6, R322.3.4
Flood Damage-Resistant Materials R322.1.8
Mechanical, Electrical Equipment
and Systems, Plumbing, Fuel Gas
R322.1.6, M1301.1.1, M1401.5,
M1601.4.9, M1701.2, M2001.4,
M2201.6, G2404.7, P2601.3,
P2602.2, P2705.1, P3001.3,
P3101.5
29
IRC Uses Step 7
7. Determine and Apply Applicable IRC Provisions
Topic IRC Section
Dry Floodproofing Not permitted
High Risk Flood Hazard Areas See floodway, V Zone requirements
and Coastal A Zone requirements:
R301.2.4, R301.2.4.1, R322.1,
R322.1.1, R322.2, R322.3
Existing Buildings: Repairs,
Renovations, Additions, Substantial
Damage and Improvement
R102.7.1, R105.3.1.1, R112.2.1,
R322.1.6, R322.3.1
Historic Buildings R112.2.1
30
IRC Uses Step 7
7. Determine and Apply Applicable IRC Provisions
Topic IRC Section
Documentation, Inspections and
Certifications (Lowest Floor
Elevation, Flood Openings , Dry
Floodproofing, Breakaway Walls, V
Zone Design)
R106.1.3, R109.1.3, R322.1.4.1,
R322.1.4.2, R322.1.10, R322.2.2,
R322.3.3, R322.3.4, R322.3.6,
31
Step 6: Permissible Foundations
Determine Permissible Foundation Types
IBC
32
Step 6: Permissible Foundations
Determine Permissible Foundation Types
IBC
33
Step 6: Permissible Foundations
Determine Permissible Foundation Types
IBC
34
IBC Uses Step 8
8. Determine and Apply Applicable IBC Provisions
Topic IBC Section
ASCE-7, ASCE-24
Basic Flood
Resistance
1612.1, 1612.4
ASCE 24-05: 1.5
Flood Loads and
Conditions
1605.2.2, 1605.3.1.2,
1612.4, 3102.7
ASCE 24-05: 1.6
ASCE 7-05: 2.3.3, 2.4.2,
5.3.1, 5.3.2, 5.4
Lowest Floor
Elevation
1603.1.7, 1612.4 ASCE 24-05: 2.3, 4.4
Foundation 1612.4, Chapter 18 ASCE 24-05: 1.5.3, 2.5,
4.5
35
IBC Uses Step 8
8. Determine and Apply Applicable IBC Provisions
Topic IBC Section
ASCE-7, ASCE-24
Use of Fill 1804.4 ASCE 24-05: 1.5.4, 2.4,
4.5.4
Basements 202, 1612.2 ASCE 24-05: 1.2, 1.5.2,
2.3
Use of Enclosed
Areas below DFE
see ASCE 24 ASCE 24-05: 2.6, 4.6
Flood Openings
in Below-DFE
Enclosures
1203.3.2(5) ASCE 24-05: 2.6.1,
2.6.2, 4.6.2
36
IBC Uses Step 8
8. Determine and Apply Applicable IBC Provisions
Topic IBC Section
ASCE-7, ASCE-24
Breakaway Walls 1403.6, 1612.5.2.3 ASCE 24-05: 1.2, 4.6
ASCE 7-05: 5.3.3
Flood Damage-
Resistant
Materials
801.5 , 1403.5, 1612.2 ASCE 24-05: 1.2, 5.0
Mechanical,
Electrical
Equipment and
Systems,
Plumbing
3001.2, 1403.6 ASCE 24-05: 4.6.1, 7.0
37
IBC Uses Step 8
8. Determine and Apply Applicable IBC Provisions
Topic IBC Section
ASCE-7, ASCE-24
Dry Floodproofing 1612.2 ASCE 24-05: 1.2, 1.5.2,
6.0, 7.1
High Risk Flood
Hazard Areas
see ASCE 24 ASCE 24-05: 3.0, 4.0
Existing
Buildings:
Repairs,
Renovations,
Additions,
SD and SI
1612.1, 1612.2, 3403.1
3403.2, 3404.2, 3405.5,
3412.2.4.1
ASCE 24-05: 1.1, 1.2,
1.5.1
38
IBC Uses Step 8
8. Determine and Apply Applicable IBC Provisions
Topic IBC Section
ASCE-7, ASCE-24
Historic Buildings 3409.2 ASCE 24-05: 1.1, 1.2
Documentation,
Inspections and
Certifications
(Lowest Floor
Elevation, Flood
Openings , Dry
Floodproofing,
Breakaway Walls,
V Zone Design)
107.2.5, 110.3.3 ,
1603.1, 1603.1.7 ,
1612.3.1, 1612.5
Not applicable
39
IBC Uses Steps 9-12*
9. Determine Design Flood Conditions
10. Calculate Design Flood Loads
11. Determine Flood Load Fa for Load
Combinations
12. Design the Foundation
* IRC users should review steps 9-12
40
Coastal Flooding:
(inundation, waves, velocity,
erosion, debris, wind)
Riverine Flooding:
(inundation, duration, velocity,
debris)
Riverine vs. Coastal Conditions
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
42
Step 9: Design Flood Conditions
Design Flood
Condition
Used For CodeMaster
Step
Notes
Stillwater
Elevation
(SWEL)
Calculating
stillwater flood
depth
9.1 Obtain from
FIS/FIRM or site-
specific
determination
Anticipated
Eroded Ground
Elevation
Calculating
stillwater flood
depth
9.2 Some sites will
not be subject to
erosion during
design flood
Stillwater Flood
Depth, ds
Calculating
hydrostatic and
hydrodynamic
loads, coastal
wave heights
9.3 Obtain by
subtracting
anticipated
eroded ground
elevation from
SWEL
43
Step 9.1: Determine Stillwater Elevation (SWEL)
44
Step 9.2: Account for Erosion and Scour
45
Step 9.3: Calculate Design Stillwater Flood Depth
46
Step 9: Design Flood Conditions
Design Flood
Condition
Used For CodeMaster
Step
Notes
Flood Velocity Calculating
hydrodynamic
loads
9.4 Estimated from
FIS or site-
specific
determination;
ASCE 7-05:
C5.4.3
Floodborne
Debris
Calculating
debris impact
loads
9.5 ASCE 7-05:
C5.4.5
Coastal Wave
Height
Calculating
breaking wave
loads (coastal
design only)
9.6 ASCE 7-05: 5.4.4
47
Step 9.4: Estimate Flood Velocity
SWEL
We often obtain or assume
depth-average velocity
48
Step 9.5: Characterize Floodborne Debris
49
Step 9.6: Estimate Coastal Wave Height
50
Step 10: Calculate Design Flood Loads
10.1 Hydrostatic Loads, Fsta and Fbuoy
10.2 Hydrodynamic Load, Fdyn
10.3 Floodborne Debris Load, Fi
10.4 Coastal Wave Load, Fbrk
51
Step 10.1: Hydrostatic Loads
52
Hydrostatic Loads
53
Step 10.2: Hydrodynamic Loads
54
Hydrodynamic Loads
Photo courtesy of http://www.flickr.com/photos/colecamplese/
55
Step 10.3: Floodborne Debris Impact Loads
56
Step 10.4: Wave Loads
57
Wave Loads
58
Step 11: Determine Flood Load Fa for Load Combinations
• ASCE 7-05 and 7-10 use a single flood load, Fa, 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
Fa, for flood loads, given the hydrostatic, hydrodynamic, wave, and
floodborne debris impact loads calculated in Step 10
59
Step 12: Design the Foundation
Assume a preliminary
foundation design
Calculate all loads acting
on the foundation and
elevated structure
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
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
61
Example Problem -- Solution
62
Example Problem
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
64
Questions
Christopher P. Jones, P.E.
Durham, NC
chris.jones@earthlink.net
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