overview of building codes and cubic national adoptions in...

World Bank ECCR Workshop in St Vincent 26 January 2012

Tony Gibbs1

Overview of building codes and CUBiCNational adoptions in the Eastern CaribbeanNational adoptions in the Eastern Caribbean

Discussion of wind loading in St Lucia

Tony GibbsConsulting Engineers Partnership Ltd


Tony Gibbs2

Codes = laws and regulations

Standards = technical provisions

History

pre CCEOpre‐CCEO

1969 – the formation of the CCEO

Timber GAPEh kEarthquakes APETT

Wind BAPEMasonry JIE


Tony Gibbs3

History

Th l 1970The early 1970sThree conferences in Jamaica

1978The First CaribbeanThe First CaribbeanEarthquake Engineering Conferencein Trinidad

History

19791979

The CaribbeanDisaster Preparedness Conferencein St Luciain St Lucia

The conception of CUBiC


Tony Gibbs4

History

1979The CARICOM Council of Ministers of Health

1980Disaster Preparedness ConferenceDisaster Preparedness Conferencein Dominican Republic(CUBiC project formulation)

History

19801980Funding meeting in Washington

1981‐82CUBiC project preparation

1982‐85CUBiC project execution


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Contents

Part 1 Administration and Enforcement of the Code

Part 2 Structural Design RequirementsPart 3 Occupancy, Fire Safety and Public

Health RequirementsS i i d SPart 4 Services, Equipment and Systems (Not Included in Present CUBiC)

Part 5 Small Buildings

ContentsPart 2 Structural Design Requirements

Section 1 Dead Load and Gravity Live LoadSection 2 Wind LoadSection 3 Earthquake LoadSection 4 Block MasonrySection 5 Foundations (not Included in Present CUBiC)Section 6 Reinforced and Prestressed ConcreteSection 7 Structural SteelSection 8 Structural Timber


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Earthquake Loadsand

Design Provisions

o Historical observations ofsuccesses and failures

o Equivalent static forces

o Dynamic analysis


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History1967 – Caracas Earthquake1971 – Key, Tomblin, Imbert1974 – Antigua Earthquake1974 Antigua Earthquake1969 – SEAOC1979 – First Caribbean Conference on

Earthquake Engineering1981‐5 – Principia Mechanica1997 C i d T b E th k1997 – Cariaco and Tobago Earthquakes2003 – Dominican Republic Earthquake2008‐10 – EUCENTRE‐SRC Study2010 – Haiti Earthquake

1967 Caracas Earthquake:soils, non‐structural infill, overturning


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Photo: David Key


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Photo: Tony Gibbs The 09 July 1997 Cariaco Earthquake north-east of VenezuelaPhoto: Tony Gibbs

Photo: Tony GibbsThe 09 July 1997 Cariaco Earthquake north-east of VenezuelaPhoto: Tony Gibbs


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The 22 Sep 2003 Earthquake north of Hispañola

Photo: Daniel ComarazamyThe 22 Sep 2003 Earthquake north of Hispañola


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NATIONAL CATHEDRAL

Photo: GADR


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Photo: Julian Jackson

Fuel Port


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Fuel Port


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Design PhilosophyProtect lives rather than property

Structures designed in conformance with the provisions d i i l f h i C iC 2 S i 3 h ldand principles set forth in CUBiC:Part‐2:Section‐3 should,

in general, be able to:

1 resist minor earthquakes without damage;2 resist moderate earthquakes without structural

damage but with some non‐structural damage;damage, but with some non structural damage;3 resist major earthquakes, of the intensity of

severity of the strongest experienced in (the target area), without collapse, but with some structural as well as non‐structural damage.


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Concrete BehaviorAsp

fyhAsp

ds

fyhAsp

Confinementfrom spiral orcircular hoop

Forces actingon 1/2 spiral orcircular hoop

Confinementfrom squarehoop

Column with spiral reinforcement


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Column with inadequate ties

Wind Loadsand

Design Provisions


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CP3 Chapter V:Part 2 – 1952

75 mph – 1‐minute average(= 93 mph or 41 m/s 3‐second gust)

Rudimentary procedures

South Florida Building Code – 1960s

120 mph – fastest mile(= 137 mph or 61 m/s 3‐second gust)

Rudimentary procedures


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The Council of Caribbean Engineering Organisations

(CCEO)(CCEO)1969

gave a mandate to theBarbados Association of Professional Engineers

(BAPE)(BAPE)to prepare a wind load standard

Tony Gibbs, AR Matthews, HC Shellard“Wi d L d f St t l D i 1970”“Wind Loads for Structural Design – 1970”

including

HC ShellardHC Shellard“Extreme Winds in the Commonwealth Caribbean”


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Our first “modern” standard

Based on the approach of the 1972 edition of the British Standard CP‐3:Chapter‐V:Part‐2 (also the guide p ( gfor the 1970s Australian standard and the Brazilian standard)

Over 80 pages:o procedures

i f d f ffi io extensive range of pressure and force coefficientso several appendices of explanatory background to

the procedures – the suitable textbook of fundamentals

Basic wind speed – V (3‐second, 33‐ft, 50‐year, open terrain)

fTopographic factor – S1

Terrain roughness, height, size –S2

Importance – S3

Design wind speed – VS = V x S1 x S2 x S3

Pressures derived from VS


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Durst-Deacon


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Suggested Basic Wind Speeds (mph, 3s)for Some Commonwealth Caribbean Countries

1970

Jamaica 120 (= 54 m/s)BVI 120 (= 54 m/s)Leeward Islands 120 (= 54 m/s)St Lucia, St Vincent 120 (= 54 m/s)Barbados 120 (= 54 m/s)Barbados 120 (= 54 m/s)Grenada, Tobago 100 (= 45 m/s)Trinidad 90 (= 40 m/s)Guyana 50 (= 22 m/s)


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1981 Revision of“Wind Loads for Structural Design” (3s)CCEO – BAPE – NCST – OASTony Gibbs – HE Browne – BA Rocheford

Procedures for aerodynamically‐sensitive structures (< 1Hz)

Jamaica 56 m/s (= 125 mph)BVI 64 m/s (= 143 mph)Leeward Islands 64 m/s (= 143 mph)St Lucia, Dominica 58 m/s (= 130 mph), / ( p )Barbados, St Vincent 58 m/s (= 130 mph)Grenada, Tobago 50 m/s (= 112 mph)Trinidad 45 m/s (= 101 mph)Guyana 22 m/s (= 49 mph)

BA Rocheford (Caribbean Meteorological Institute) 1984 Revision of Wind Speeds – 10‐minute

Belize – Centre 29.0 m/s (= 65 mph) [= 93 mph 3s] Jamaica – N 37.0 m/s (= 83 mph) [= 119 mph 3s]Jamaica – S 41.0 m/s (= 92 mph) [= 132 mph 3s]St Kitts 44.5 m/s (= 100 mph) [= 143 mph 3s] Antigua 46.0 m/s (= 103 mph) [= 147 mph 3s] Dominica 41.0 m/s (= 92 mph) [= 132 mph 3s]St Lucia 43 0 m/s (= 96 mph) [= 137 mph 3s]St Lucia 43.0 m/s (= 96 mph) [= 137 mph 3s]Barbados 42.0 m/s (= 94 mph) [= 134 mph 3s]Tobago 31.5 m/s (= 70 mph) [= 100 mph 3s]Trinidad – Central 27.5 m/s (= 62 mph) [= 89 mph 3s]


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The Caribbean Uniform Building Code (CUBiC:1985)The Boundary Layer Wind Tunnel Laboratory (University of Western Ontario)Davenport – Surry – Georgioup y g

Simulation of hurricane wind climate using:o drop in barometric pressure;o radius of the ring to maximum wind speeds;o translation speed;o angle of its track;o angle of its track;o position of the point of interest relative to the

centre of the storm.


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CUBiC:1985 (forerunner of ISO 4354:1997)UWO‐BLWTL

o Reference pressures (10‐minute average wind speeds

o adjustments for height and ground roughness; shape and size; dynamic response:response:

w = (qref)(Cexp)(Cshp)(Cdyn)

CUBiC Part 2 Section

2


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Maximum Wind Speeds (50‐year return)

W

23 N

CDMP

89.5

59 W

9 N

Wind Speeds

0 1 2 3 4 5knotsmph

kph

m/s

Storm Category

25 50 75 100 125

25 50 75 100 125 150

50 100 150 200 250

10 20 30 40 50 60 70


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Ir P C van Staalduinenand

Dr Ir C P W GeurtsDr Ir C P W GeurtsTNO (Netherlands Organisation for Applied Scientific Research)

“Hurricane Hazardin the Netherlands Antilles ”in the Netherlands Antilles ….

1997


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1999: CARICOM decision to adopt and adaptthe I‐codes of the ICC

2000: The I‐codes adopt by referencethe wind load provisions of the ASCE 7.

2008: PAHO executed a project, funded by USAID for the preparation of theUSAID for the preparation of the Caribbean Application Document (CAD) for ASCE 7‐05 Ch 6.

TheThe trendtrend forfor CaribbeanCaribbean standardsstandardsisis toto adoptadopt and and adaptadaptthethe ASCEASCE‐‐7 7 approachapproach

(Dominican Republic new CUBiC Cayman Bahamas)(Dominican Republic, new CUBiC, Cayman, Bahamas)


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Wind Hazard Mapsfor the Caribbean Basin(3‐second mph at 33ft)(3 second mph at 33ft)

Overall region and individual islandsApril 2008

Principal researcher – Applied Research Associates (Peter Vickery)Regional coordinator – Tony Gibbs (CEP International Ltd)

Executing agency – Pan American Health Organisation (Dana van Alphen)Funding agency – United States Agency for International Development

(Tim Callaghan and Julie Leonard)

Caribbean Basin Wind Hazard Maps:

a series of overall, regional, wind‐hazard maps using uniform, state‐of‐the‐art approaches covering all of the Caribbean islands and the Caribbean coastal areas ofislands and the Caribbean coastal areas of South and Central America.


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Contour plots of modelled minimum central pressures (mbar) 50 year return period. Contours represent the minimum pressure anywhere

within 250 km of a point

130

120

120120

130

120 110

120

50‐Year Wind Speeds for Caribbean

110

100908070

6050

40

30

130

120 130

100

120

110100

90

90


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140

130

140 130

130

140130


1201101009080

7060

50

40

140

150

120

130

120110

100

150 140

120

40

30110

100

30

180180

170170

160

160

170

160


15014013012011010090

80

160

190

170

160150140130

70150140130120


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190180

190 180

170

170

180

170


170

160150140130120110100

90

200

190

170160150

80

160150140


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Peak gust wind speeds ( )

Return period (years)Location1700700

miles per hour10282Trinidad (S)156136Trinidad (N)128100Isla Margarita168154Grenada 156149Bonaire168147Curacao162146Aruba169152Barbados(mph) in flat

open terrain as a function of return period for selected

169152Barbados171155Saint Vincent172155Saint Lucia171159Martinique172159Dominica168157Guadeloupe172164Montserrat170163St. Kitts and Nevis168160Antigua and Barbuda178168Saint Martin/Sint Maarten176166Anguilla176167US Virgin Islandsselected

locations in the Caribbean

176167US Virgin Islands180169British Virgin Islands200187Grand Cayman197178Little Cayman/Cayman Brac162150Turks & Caicos (Grand Turk)170155Turks & Caicos (Providenciales)180165Eleuthera180162Andros180163New Providence (Nassau)178162Great Abaco175161Grand Bahama (Freeport)177165Belmopan

2.0

2.5

3.0

d Fa

ctor

Non-HurricaneHurricane

0.0

0.5

1.0

1.5

Win

d Lo

ad

Wind load factor (VT/V50)2

for Hurricane and Non‐Hurricane Wind Speedsplotted vs return period

1 10 100 1000 10000Return Period (Years)


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0.5

1.0

1.5

2.0

2.5

3.0

Win

d Lo

ad F

acto

r

Non-HurricaneHurricane

0.01 10 100 1000 10000

Return Period (Years)

Contour plots of (V700/V50)2


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1.2

1.21.2

1.2

1.3

1.2

1.2

1.2

1.21.3

1.41.51.6 1 7 1 8 2 1 9

1.1

1.11.2

1.2

1.2

1 5

1.1

1.3

1.3 1.2

1 7

1.2

1.3

1.31.4

1.5

Contour plots of importance factorfor ASCE category III and IV structures

defined by I=(V1700/V700)2

1.7 1.8 2 1.91.5 1.71

o ASCE 7 Basic Wind Speed, V – 3‐sec, 33 ft height, Exposure C, 50 years

o For same level of safety in the Caribbean a pseudo‐50‐year wind speed = V700/ √1.6 must be used 700

instead of the real V50.

o Alternatively the real V50 could be used with an upward adjustments to the Load Factors and Importance Factors.

o Alternatively, the Basic Wind Speed could be taken y, pas V700 for Category II buildings and V1700 for Categories III and IV buildings, with the Load Factor and Importance Factor = 1. This last approach will be simpler in a regional context.


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The 700‐year Return Period:

1 50‐year return period for non‐hurricane areas

2 Load factor = 1.63 Failure load produced by 50‐

year wind speed x √1 6year wind speed x √1.64 Use 700‐year wind with load

factor of 1

Load Combinations(factored loads using strength design)

1: 1.4(D + F)1: 1.4(D + F)2: 1.2(D + F + T ) + 1.6(L + H) + 0.5(Lr or S or R)3: 1.2D + 1.6(Lr or S or R) + (L or 0.8W)3a: 1.2D + 1.6(Lr or R) + (L or 0.8W700/1.6)4: 1.2D + 1.6W + L + 0.5(Lr or S or R)4a: 1.2D + 1.0W700 + L + 0.5(Lr or R)5: 1.2D + 1.0E + L + 0.2S6: 0.9D + 1.6W + 1.6H6a: 0.9D + 1.0W700 + 1.6H7: 0.9D + 1.0E + 1.6H


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SYMBOLS AND NOTATIOND = dead loadDi = weight of iceE = earthquake loadF = load due to fluids with well‐defined pressures and F load due to fluids with well defined pressures and maximum heightsFa = flood loadH = load due to lateral earth pressure, ground water pressure,or pressure of bulk materialsL = live loadLr = roof live loadR = rain loadS = snow loadT = self‐straining forceW = wind loadWi = wind‐on‐ice determined in accordance with Chapter 10

Load Combinations(nominal loads using allowable stress design)

1: D + F2: D + H + F + L + T2: D + H + F + L + T3: D + H + F + (Lr or S or R)4: D + H + F + 0.75(L + T ) + 0.75(Lr or S or R)5: D + H + F + (W or 0.7E)5a: D + H + F + (W700/1.6 or 0.7E)6: D+H+F+0.75(W or 0.7E)+0.75L+0.75(Lr or S or R)6 0 5( o 0 ) 0 5 0 5( o S o )6a: D+H+F+0.75(W700/1.6 or 0.7E)+0.75L+0.75(Lr or R)7: 0.6D + W + H7a: 0.6D + W700/1.6 + H 8: 0.6D + 0.7E + H


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ASCE 7 was written for the USA hi h h i t f h iwhich has a mixture of hurricane‐

prone regions and non‐hurricane regions. The CAD will eliminate all references to non‐hurricanereferences to non hurricane regions.

ASCE 7 allows three methods for d i i i d fdetermining wind forces on structures:

Method 1: Simplified (tables & limited use)Method 2: Analytical (almost all cases)Method 3: Wind Tunnel (unusual cases)Method 3: Wind Tunnel (unusual cases)


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Method 1: SimplifiedThe building must be:1. a simple diaphragm building;2. a low‐rise building;3. enclosed and conform to the wind‐borne debris

provisions;4. a regular shaped building or structure;5. not classified as a flexible building;6. not assessed as having unfavourable aerodynamic

characteristics and not having an unfavourable sitecharacteristics and not having an unfavourable sitelocation;

7. of a structure with no expansion joints or separations;8. not subject to unfavourable topographic effects;9. of an approximately symmetrical cross section.

Method 2: AnalyticalThe Design Procedure requires the following steps:

1. basic wind speed V and wind directionality factor Kd2. importance factor I2. importance factor I3. exposure category or exposure categories and

velocity pressure exposure coefficient Kz or Kh4. topographic factor Kzt5. gust effect factor G or Gf, 6. enclosure classification7 Internal pressure coefficient Gc7. Internal pressure coefficient Gcpi8. External pressure coefficients Cp or GCpf , or force

coefficients Cf9. Velocity pressure qz or qh, 10. Design wind load p or F


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o A lengthy process but, ASCE 7 provides most of the answers in tables and figures.

o A growing reliance on proprietary software for the use of computers in the determination of wind forces

o The negative effect of reducing the understanding of engineers in the fundamentals of wind forces on structures –more likely that gross errors would occur

There is debate over the wind directionality factor K where it isdirectionality factor Kd where it is applied to round chimneys and similar shaped structures.

(See Rolando Vega’s paper.)


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The penalties in the form of increased loads for buildings without impact‐resistant glazing or impact‐resistant, permanently‐installed shutters are severe. This should provide significant impetus for owners, designers and builders to

dincorporate impact‐resistant windows or shutters in buildings.

o Topographic effects are very important in most Caribbean countriescountries.

o This issue receives attention in ASCE 7. Wind speed‐up is recognised over hills, ridges, and escarpments.hills, ridges, and escarpments.

o Valleys are missing.


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Photo: UWO‐BLWTL

Sketch Sketch showingshowing effectseffects of of topographytopography

onon windwind velocityvelocity onon a a hillyhilly islandisland

100gV

80Vs

100Vg

60

gV100

g

120sV

Vs

V

40

100

Speed up

10 ms Vs

Open sea Winward Speed up over Sheltered leeward

coastCoast hill crest


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Probability 1% / year, 100-Year Return Time

Winds

Antigua

61.9

25 W

17.20 N

61. 65 W

1

22. Parham

Desalinization plant 50 m/sW t f t b t 47 /

1. St. John’sDowntown 47 m/sEast side of town 51 m/s

RC

-MIN

UT

ES

KIL

OM

ET

ER

S

Ross Wagenseilfor PGDMApril 2001

3

4

2

N

3. English and Falmouth HarboursNelson’s Dockyard 48 m/s Falmouth SE 41 m/sFalmouth NW 52 m/s

Waterfront by town 47 m/sHill above town 53 m/s

4. Jolly HarbourChannel entrance 45 m/sInner boat basin 44 m/sBeach front 45 m/s

Directory Topo. Map

Wind Speeds

0 1 2 3 4 5knotsmph

m/s

Storm Category25 50 75 100 125

25 50 75 100 125 150

50 100 150 200 25010 20 30 40 50 60 70

Wind

Wave

Surge

10yr 25yr 50yr 100yr

Min Max

5

AR

0

5

0

10

MIL

ES

0

5

PGDMMay200116.98 N

100-Year Return Time

DominicanRepublic

Winds

72 W

20.17 N

68

CDMP

DE

GR

EE

S

LO

ME

TE

RS

MIL

ES

100

Ross Wagenseilfor CDMPJanuary 2000

8 W

N

Wind Speeds

0 1 2 3 4 5knotsmph

kph

m/s

Storm Category

25 50 75 100 125

25 50 75 100 125 150

50 100 150 200 250

10 20 30 40 50 60 70

0

0.5

1

0

50

100

KIL

0

25

50

100

17.5 N

West Basin Mid-

BasinEastBasin

Caribbean

Wind

Wave

Surge

10yr 25yr 50yr 100yr

Return to Directory


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Risk Management Solutions

Topographic effectTopographic effect

showing wind velocity increaseshowing wind velocity increase

x

z

HH/2

x

z

z

x

H/2

x

H

z

speed up

(leeward)

V(z)

(windward)V(z)

(windward)V(z)

speed up

(leeward)

V(z)

Hill

mL

H

H/2 H/2

Escarpment

mL

H


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Pre‐Ivan photograph by Brooks La TouchePre-Ivan photograph by Brooks La Touche


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The National Stadium

Photo: Tony Gibbs

Method 3 – Wind Tunnel Procedure

o Wind tunnel testing is no longer unknown i th d i f C ibb b ildiin the design of Caribbean buildings.

o Used for:‐ overall loads on the main wind‐force

resisting systems;‐ pressures on external cladding;‐ pedestrian conditions adjacent to

buildings.


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Present Standards and Codes• CUBiC and national codes

– Barbados– Belize– OECS (9 states)

• Bahamas – South Florida Building Code• Cayman – Southern Building Code Congress International

• TCI – hybrid (USA and CUBiC)• Guyana (?)• Jamaica (IBC)• Trinidad & Tobago (in preparation)


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The New CUBiC (or CUBiS)to be based on the IBC

CUBiS countries:BarbadosBelizeGuyanaJamaicaTrinidad & TobagoOECS (9 states)

Other similar countriesOther similar countriesBahamas – SFBC >> IBCCayman – SBCCI >> IBCTCI – hybrid >> IBCDominican Republic >> IBC approach

Components(agreed by CCEO & CARICOM in March 1999)

1 Caribbean Application Document (CAD) based on IBC

2 CaribbeanResidential Design Standards

3 Model Laws and Regulations


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Components

1 Caribbean Application Document(CAD) based on IBC

a Use IBC 200? (The soon to be published version is 2006.)

b Delete clauses ??c Amend clauses ?? by replacing

them with ……d Add clauses as follows:

Components

2 C ibb R id i l S d d2 Caribbean Residential Standards

a Not necessarily based onIRC 200?

b Consistent with the CADb Consistent with the CADc Prescriptive and necessarily

more conservative than CAD


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Components

3 Model Laws and Regulations3 Model Laws and Regulations

a Each Caribbean state may wish to have its own laws and regulations.

b It ld b d i bl if thb It would be desirable if there were similarities of approach and content.

Country Standards Laws Enforcement

Anguilla Y Y YAntigua Y Y Y ?Bahamas Y Y YBarbados Y N NBelize Y N NBelize Y N NBVI Y Y Y ?Cayman Y Y YDominica Y Y ? NGrenada Y Y Y ?Guyana N N NJamaica Y Y Y

Status

Montserrat Y Y YSt Kitts Y Y Y ?St Lucia Y N NSt Vincent Y N NTCI Y Y YTrinidad N Y Y


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AMO = Atlantic multi‐decadal oscillations


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NAtl = North Atlantic

The Impact of Climate Change on Design Wind Speeds in

Saint Lucia

2008

Peter J. Vickery


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Percentage Increase in Basic Wind Speed in Lucia vs. Percentage Increase in Annual Rates of

Category 4 and 5 Hurricanes

15%

10%

n Basic W

ind Speed

Category II Buildings

113

0%

5%

0% 50% 100% 150% 200% 250% 300% 350%

Increase in

g y g

Category III and IV Buildings

Projections

• According to Curry et al. (2007), there could be an average of three to four Category 4 and 5 hurricanes per year by 2025 in the Atlantic Basin ThisCategory 4 and 5 hurricanes per year by 2025 in the Atlantic Basin . This represents a 210‐ to 280‐percent increase in the number of Category 4 and 5 hurricanes compared to the long‐term (1944‐2007) average of 1.4 Category 4 and 5 hurricanes per year.

• If this were the case, the basic wind speeds for Category II buildings in Saint Lucia should be increased by about 12 to 14 percent, and the basic wind speeds for Category III and IV buildings should be increase by about 10speeds for Category III and IV buildings should be increase by about 10 percent. Note that the increases in the basic wind speeds assume that the hurricane hazard remains elevated for the expected life of the building.

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