meteorological hazards · 2019-05-22 · meteorological hazards ttia cpd seminar 23 july 2018 tony...

Meteorological HazardsTTIA CPD Seminar

23 July 2018

Tony Gibbs FREng 1

The Trinidad and Tobago Institute of ArchitectsCPD Seminar

July 2018

Meteorological Hazards(wind, rain, surge, waves)

Tony Gibbs FREng HonTTIASecretary General of CCEO

• Historical development of the wind hazard for building design in the Caribbeano wind speeds

o topographic effects

o climate change

o the 2017 hurricane season

• Intensity-duration-frequency relationships and rational storm-water drainage design

• Regional maps of storm surge and waves


23 July 2018

Tony Gibbs FREng 2

Historical developmentof the wind hazard

wind speeds


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Tony Gibbs FREng 3

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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Tony Gibbs FREng 4

The Council of Caribbean Engineering Organisations

(CCEO)1969

gave a mandate to theBarbados Association of Professional Engineers

(BAPE)to prepare a wind load standard

Tony Gibbs, AR Matthews, HC Shellard“Wind Loads for Structural Design – 1970”

including

HC Shellard“Extreme Winds in the Commonwealth Caribbean”


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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)Grenada, Tobago 100 (= 45 m/s)Trinidad 90 (= 40 m/s)Guyana 50 (= 22 m/s)

1971 – Norris Helliwell


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

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)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]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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Tony Gibbs FREng 7

Wind Speed Averaging Time A Point of Confusion

Peter Vickery

Durst-Deacon


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

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 position of the point of interest relative to the

centre of the storm.


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CU

BiC

Par

t 2

Sec

tio

n 2


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Maximum Wind Speeds (50-year return)

CDMP

9 N

89

.5 W

23 N5

9 W

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

Ir P C van Staalduinenand

Dr Ir C P W GeurtsTNO

(Netherlands Organisation for Applied Scientific Research)

“Hurricane Hazard in the Netherlands Antilles ….”

1997


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Tony Gibbs FREng 11

Wind Hazard Maps for the Caribbean Basin

(3-second mph at 33ft) Overall region and individual islands

April 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)


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Tony Gibbs FREng 12

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 of South and Central America

Contour plots of modelled minimum central pressures (mbar) 50 year return period. Contours represent the minimum pressure anywhere within 250 km of a point


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Tony Gibbs FREng 13

130

120

110

100

9080

70

60

50

40

30

130

120120

130

120 110

120 130

100

90

120

110100

90

50 Year Wind Speeds for Caribbean

140

130

120

110

100

9080

70

60

50

40

30

140

140

150

130

130

140130

120

110

100

30

130

120110

100

150140

120



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180180

170

170

150

140130120110

100

90

80

70

160

190

160

170

160

150140130120

170

160150140130


190

180

170

160150140130120110

100

90

80

190180

170

170

180

200

190

160150140

170

170160150



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Peak gust wind speeds (mph) in flat open terrain as a function of return period for selected locations in the Caribbean

Return Period (years)Location

1700700

11087Trinidad (S)147128Trinidad (N)

152133Isla Margarita168154Grenada165149Curacao156149Bonaire162146Aruba169152Barbados171155Saint Vincent172155Saint Lucia171159Martinique172159Dominica168157Guadeloupe172161Montserrat161150Belize170163St. Kitts and Nevis168160Antigua and Barbuda175167Saint Martin/Sint Maarten176165Anguilla176167US Virgin Islands180169British Virgin Islands198187Grand Cayman197178Little Cayman/Cayman Brac162150Turks & Caicos (Grand Turk)170155Turks & Caicos (Providenciales)180162Andros180165Eleuthera180163New Providence (Nassau)178162Great Abaco175161Grand Bahama (Freeport)

Wind load factor (VT/V50)2

for Hurricane and Non-Hurricane Wind Speedsplotted vs return period

0.0

0.5

1.0

1.5

2.0

2.5

3.0

1 10 100 1000 10000

Return Period (Years)

Win

d L

oad

Fac

tor

Non-Hurricane

Hurricane


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Contour plots of (V700/V50)2

Contour plots of importance factorfor ASCE category III and IV structures

defined by I=(V1700/V700)2

1.2

1.3

1.41.51.6 1.7 1.8 2 1.9

1.1

1.11.2

1.2

1.2

1.2

1.2

1.5

1.1

1.2

1.3

1.3 1.2

1.2

1.3

1.7

1.2

1.2

1.3

1.2

1.3

1.4

1.2

1.5


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0.0

0.5

1.0

1.5

2.0

2.5

3.0

1 10 100 1000 10000

Return Period (Years)

Win

d L

oa

d F

ac

tor

Non-Hurricane

Hurricane

(Vrare/Vfrequent) increases with closeness to the equator


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The 1933 Hurricane


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Tony Gibbs FREng 20

Trinidad HurricaneWilmoth Houdini and his Humming BirdsNew York 19 October 1933

The Catholic priest, Reverend Father John,Told the story how the storm began,He said it was about ten o’clock,When Cedros got the fatal shock,A man, a woman and three children cried,The woman was hit by a flying galvanise,My sympathies extended to the land of Iëre,Sans d’humanite

topographic effects


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Tony Gibbs FREng 21

o Topographic effects are very important in most Caribbean countries.

o This issue receives attention in most modern wind-loading standards. Wind speed-up is recognised over hills, ridges, and escarpments.

o Valleys are sometimes missing.

Photo: UWO-BLWTL


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Tony Gibbs FREng 22

Sketch showing effects of topography

on wind velocity on a hilly island

10 m80Vs

100Vg

60

gV100

g

120sV

Vs

V

100gV

40

100

Open sea Winward Speed up over Sheltered leewardcoast

Speed up

Coast hill crest

Probability 1% / year, 100-Year Return Time

Wind Speeds

0 1 2 3 4 5knotsmph

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

Winds

Antigua

Wind

Wave

Surge

10yr 25yr 50yr 100yr

Min Max

5

AR

C-M

INU

TE

S

0

5

KIL

OM

ET

ER

S

0

10

MIL

ES

0

5

Ross Wagenseilfor PGDMApril 2001

PGDMMay200116.98 N

61.9

25 W

17.20 N

61. 65 W

1

3

4

2

N

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

2. ParhamDesalinization plant 50 m/sWaterfront by town 47 m/sHill above town 53 m/s

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

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

Directory Topo. Map


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Tony Gibbs FREng 23

N

100-Year Return Time

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

DominicanRepublic

Winds

0

0.5

1

0

50

100

DE

GR

EE

S

KIL

OM

ET

ER

S

MIL

ES

0

25

50

100

Ross Wagenseilfor CDMPJanuary 2000

17.5 N

72 W

20.17 N

68 W

CDMP

West Basin Mid-

BasinEastBasin

Caribbean

Wind

Wave

Surge

10yr 25yr 50yr 100yr

Return to Directory

Risk Management Solutions

Hurricane Georges in Puerto Rico – 1998


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Tony Gibbs FREng 24

Topographic effect

showing wind velocity increase

ASCE 7

Hill

mL

x

z

H

H/2

H/2

x

z

z

x

H/2

H/2

Escarpment

mL

x

H

z

speed up

(leeward)

V(z)

(windward)V(z)

(windward)V(z)

speed up

(leeward)

V(z)

Tortola, British Virgin Islands


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


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Tony Gibbs FREng 26

The Grenada National Stadium

Photo: Tony Gibbs

Climate ChangeFake Science?


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Tony Gibbs FREng 27

Hurricane Catarina as it approached the Brazilian shore at midday on 27 March 2004.

(Illustration courtesy Greg Holland; satellite data courtesy NOAA/University of Wisconsin.)

Hurricane Ivanjust before striking Grenada

Central Pressure 956 mbarPeak Gust Wind ~135 mph

“The most intense hurricane ever recorded so close to the equator in the North Atlantic” – NHC


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Tony Gibbs FREng 28

A new World SurfaceWind Gust Recordwas registered at

the Paso Real de San Diegometeorological station (78317)

in Pinar del Rio, Cuba,during hurricane Gustav.

The Dinespressure tube anemometer

recorded a gust of340 km/h (=211mph).

Hurricane Gustav 2008


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Tony Gibbs FREng 29

AMO = Atlantic multi-decadal oscillations


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Tony Gibbs FREng 30

Percentage Increase in Basic Wind Speed in Eastern Caribbean vsPercentage Increase in Annual Rates of Cat 4 and 5 Hurricanes

0%

5%

10%

15%

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

Increase in Basic Wind Speed

Increase in Annual Frequency of Category 4 and 5 Hurricanes

Category II Buildings

Category III and IV Buildings


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Tony Gibbs FREng 31

the 2017 hurricane season


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Tony Gibbs FREng 32

164‐181 mph gust ove

r land

= Categ

ory 4‐5 Hurrican

e16


r land

= Categ

ory 4‐5 Hurrican

e


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Tony Gibbs FREng 33


r land

= Categ

ory 4‐5 Hurrican

e16


r land

= Categ

ory 4‐5 Hurrican

e


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Tony Gibbs FREng 34

Cat 3‐4 HurricaneCat 3 Hurricane

Cat 5 Hurricane > 173 mph gust over land

165-182 mph gust over land= Category 4-5 Hurricane


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Tony Gibbs FREng 35

rainfallintensity-duration-frequency


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Tony Gibbs FREng 36

72


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Tony Gibbs FREng 37

Title of the Presentation73

mapsstorm surge and waves


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Tony Gibbs FREng 38

Maximum Storm Surge (50-year return)

Surge Heights

1 2 3 4 5 6

5 10 15 20

Meters

Feet

Maximum Wave Heights (50-year return)

CDMP

9 N

89

.5 W

23 N

59

W

Wave Heights

Meters

Feet

1 2 3 4 5 6 7

5 10 15 20 25

meteorological hazards · 2019-05-22 · meteorological hazards ttia cpd seminar 23 july 2018 tony...

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