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

Christopher P. Jones, P.E.

[email protected]

Flood Resistant Design CodeMaster Webinar

May 14, 2014

mailto:[email protected]

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/

http://www.skghoshassociates.com/

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


• 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




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




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




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


26



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


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


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


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


Determine Permissible Foundation Types

IBC

32



IBC

33



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


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


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


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


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

[email protected]

Documents

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