Meteorological Hazards 23 July 2018 TTIA CPD Seminar

The Trinidad and Tobago Institute of Architects CPD Seminar July 2018 Meteorological Hazards (wind, rain, surge, waves)

Tony Gibbs FREng HonTTIA Secretary General of CCEO

• Historical development of the wind hazard for building design in the Caribbean o 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

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Historical development of the wind hazard

wind speeds

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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) 1969

gave a mandate to the 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 – OAS Tony 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, 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] 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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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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Maximum Wind Speeds (50-year return)

23 N 89.5 W 89.5 59 W

CDMP

9 N Wind Speeds Storm Category 012345 knots 25 50 75 100 125 mph 25 50 75 100 125 150

kph 50 100 150 200 250 m/s 10 20 30 40 50 60 70

Ir P C van Staalduinen and Dr Ir C P W Geurts TNO (Netherlands Organisation for Applied Scientific Research)

“Hurricane Hazard in the Netherlands Antilles ….”

1997

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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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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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50 Year Wind Speeds for Caribbean

120 130 120 120 110 120 130 120 110 100 110 100 90 80 90 70 60 130 50 120 130 40

30 100 90

100 Year Wind Speeds for Caribbean

130

140 130 130 140 140 130 130 120 110 120 110 100 100 90 150 80 120 70 60 140 150 140 50 120

40 110 30 100

30

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700 Year Wind Speeds for Caribbean

180 160 180 170 160 170

170 160

150

140 150 160 130 130 140 120 110 100 190 90 170

80 70 150 140 130 120

1700 Year Wind Speeds for Caribbean

170 190 170 190 180 180 170 180 170

160 150 170 140 150 160 130 120 110 200 100 190

90 80

160 150 140

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Location Return Period (years) 700 1700 Trinidad (S) 87 110 Trinidad (N) 128 147 Isla Margarita 133 152 Grenada 154 168 Curacao 149 165 Bonaire 149 156 Peak gust wind Aruba 146 162 Barbados 152 169 speeds (mph) in flat Saint Vincent 155 171 Saint Lucia 155 172 159 171 open terrain as a Dominica 159 172 157 168 function of return 161 172 Belize 150 161 period for selected St. Kitts and Nevis 163 170 Antigua and Barbuda 160 168 locations in the /Sint Maarten 167 175 165 176 US Virgin Islands 167 176 Caribbean British Virgin Islands 169 180 Grand Cayman 187 198 Little Cayman/Cayman Brac 178 197 Turks & Caicos (Grand Turk) 150 162 Turks & Caicos (Providenciales) 155 170 Andros 162 180 Eleuthera 165 180 New Providence (Nassau) 163 180 Great Abaco 162 178 Grand Bahama (Freeport) 161 175

3.0 Non-Hurricane 2.5 Hurricane

2.0

1.5

1.0 Wind Load Factor Load Wind 0.5

0.0 1 10 100 1000 10000 Return Period (Years) 2 Wind load factor (VT/V50) for Hurricane and Non-Hurricane Wind Speeds plotted vs return period

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2 Contour plots of (V700/V50)

1.2

2 . 2 . 1

1 1 .2 1 .2 1.2

.3

1 1.2

2 . 3 1.2

. 1

1 .2 1 1.1 1. 1 1

. 1

3

.

1 1.2 .2 1 1.3

3

1. 1.2 1.3 1. 1.4 .5 4 .5 1.6 1 1 1.5 1.7 1.7 1.8 2 1.9

Contour plots of importance factor for ASCE category III and IV structures 2 defined by I=(V1700/V700)

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3.0 Non-Hurricane 2.5 Hurricane

2.0

1.5

1.0 Wind Load Factor Load Wind 0.5

0.0 1 10 100 1000 10000 Return Period (Years) (Vrare/Vfrequent) increases with closeness to the equator

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The 1933 Hurricane

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Trinidad Hurricane Wilmoth Houdini and his Humming Birds New 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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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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Sketch showing effects of topography on wind velocity on a hilly island

100 Vg

Speed up

120 Vs

V 100 100 100 g Vg Vg

80 60 40 Vs Vs 10 m

Open sea Winward Speed up over Sheltered leeward Coast hill crest coast

Winds 17.20 N Probability 1% / year, 100-Year Return Time Antigua 61.925 W 61.925 1. St. John’s 61. 65 W Downtown 47 m/s East side of town 51 m/s 1

2. Parham Desalinization plant 50 m/s Waterfront by town 47 m/s Hill above town 53 m/s Ross Wagenseil2 for PGDM 3. English and Falmouth Harbours Nelson’s Dockyard 48 m/s April 2001 Falmouth SE 41 m/s Falmouth NW 52 m/s

4. Jolly Harbour 4 Channel entrance 45 m/s Inner boat basin 44 m/s Beach front 45 m/s

N Directory Topo. Map

KILOMETERS 3

ARC-MINUTES 10 10yr 25yr 50yr 100yr 5 PGDM MILES May Wind 16.98 N 5 2001 Wave Surge Wind Speeds

5 Storm Category 012345 knots 25 50 75 100 125 mph 25 50 75 100 125 150 50 100 150 200 250 m/s 10 20 30 40 50 60 70 0 0 0 Min Max

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Winds 20.17 N CDMP

100-Year W 72 Return Time Dominican Republic 68 W

Ross Wagenseil for CDMP January 2000 MILES DEGREES 100

1 KILOMETERS 100 N 17.5 N

50 Return to Directory Caribbean Wind Speeds West Basin Mid- 0.5 East 50 Storm Category 0 1 23 4 5 Basin Basin 25 knots 25 50 75 100 125 10yr 25yr 50yr 100yr mph 25 50 75 100 125 150 Wind 0 kph 0 0 50 100 150 200 250 Wave m/s 10 20 30 40 50 60 70 Surge

Hurricane Georges in Puerto Rico – 1998

Risk Management Solutions

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Topographic effect showing wind velocity increase ASCE 7

z z

z V(z) z V(z) speed up speed up x x x (windward) x (windward) (leeward) V(z) V(z) (leeward) H/2 H/2 H H L L m H/2 m H/2

Hill Escarpment

Tortola, British Virgin Islands

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

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Photo: Tony Gibbs

The Grenada National Stadium

Climate Change Fake Science?

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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 Ivan just before striking Grenada

Central Pressure 956 mbar Peak Gust Wind ~135 mph

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

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Hurricane Gustav 2008

A new World Surface Wind Gust Record was registered at the Paso Real de San Diego meteorological station (78317) in Pinar del Rio, Cuba, during hurricane Gustav. The Dines pressure tube anemometer recorded a gust of 340 km/h (=211mph).

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AMO = Atlantic multi-decadal oscillations

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

15%

10%

Category II Buildings 5% Category III and IV Buildings Increase in Basic Wind Speed

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

Increase in Annual Frequency of Category 4 and 5 Hurricanes

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the 2017 hurricane season

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over

Hurricane

5 ‐ gust 4

mph

181 ‐ Category

= 164 land

over

Hurricane

5 ‐ gust 4

mph

181 ‐ Category

= 164

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over

Hurricane

5 ‐ gust 4

mph

181 ‐ Category

= 164 land

over

Hurricane

5 ‐ gust 4

mph

181 ‐ Category

= 164

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Cat 3 Hurricane Cat 3‐4 Hurricane

Cat 5 Hurricane > 173 mph gust over land

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

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rainfall intensity-duration-frequency

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72

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73 Title of the Presentation

maps storm surge and waves

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Maximum Storm Surge (50-year return)

Surge Heights

Meters 12 3 45 6 Feet 5 10 15 20

Maximum Wave Heights (50-year return)

23 N 89.5 W 89.5 59 W

CDMP

9 N

Wave Heights

Meters 1 2 3 4 5 6 7 Feet 51015 20 25

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