DISSERTATION TOPIC
DESIGN INVOLVEMENT IN DISASTER MANAGEMENT (CYCLONE)
SUBMITTED BY: RAJESH KUPPILI A/2105/2009 GUIDE
–
MR.WILLS THOMAS
SECTION-A
COORDINATORs –
PROF. JAYA KUMAR,
B.Arch. IV YEAR
–
Dr. RANJANA MITTAL
School of Planning and Architecture, New Delhi Department of Architecture New Delhi
ACKNOWLEDGMENTS Many people contributed to this work in large and small ways. Foremost, I am grateful to my Coordinator:Dr. Ranjana Mittal , Prof.Jaya Kumar and my sincere thanks to my guide : Mr. Wills Thomas for having faith in my ideas but also the vision to steer me away from distractions and toward my strengths. They taught me how to use and refine my skills. I often did not see where they were guiding me until I realized I had taken my own steps forward. The insights and support of Prof.Swaroop and Prof Wason were invaluable. It was a pleasure to spend time with such rich and expansive thinkers. I am also extremely grateful for information and support provided by the NIDM members
I would like to thank my Dad Mr.K.Suryanarayana Patnaik , Mom Rama Kumari and Brother Rakesh for their support in all the possible ways.I am particularly indebted to my friend Nalin Singh,Dheeraj Aluri, who helped me in the study. I am, of course, in deepest debt to the people who I interviewed and surveyed. Their honesty and willingness to share their experiences are what made this work Possible.
Finally, I would like to thank my family and friends for making this not only possible, but fun as well. I feel this is a great opportunity to contribute myself for a research like this which can help many people who suffered and may get suffered in future . I hope my little contribution to this work may lead to a good result and free the man kind from coming sufferings.
Thanking You,
Rajesh Kuppili.
CONTENT: CHAPTER-1 – INTRODUCTION……………………………………………….………1-5 1.1. BACKGROUND…………………………………………………………….……2 1.2. RESEARCH QUESTION ………………………………………..……….……3 1.3. SCOPE,OBJECTIVES AND NEED IDENTIFICATION …………….………3 1.4. METHODOLOGY AND LIMITATIONS ………………………………………5 CHAPTER-2 - LITERATURE SURVEY………………………………………………6-25 2.1. WHAT ARE CYCLONES? ……………….……………………………….……7 2.2. IMPACT OF CYCLONES ………………………………………………………9 2.2.1. ON LIFE (HUMAN/ANIMAL/NATURE)…………………………..…….16 2.2.2. BUILDINGS……………………………………………………….………16 2.3. MITIGATION MEASURES IN INDIA AND OUT SIDE INDIA……………..20
CHAPTER-3 - CYCLONIC REPORTS ………………………………………..……26-34 3.1. AROUND THE WORLD IN PAST 4 CENTURIES………………………….27 3.2. CASE STUDIES FROM INDIA…………………………………………….…32 3.2.1. PRIMARY : OWN EXPERIENCE (AILA CYCLONE) ……….…32 3.2.2. SECONDARY : ORISSA -1999…………………… …………………33 CHAPTER-4 – OBSERVATIONS……………………………………………...……35-46 4.1. RESEARCH ON CYCLONE RESISTANT ARCHITECTURE ……………36 4.2. CONCLUSION/ADVICES ……………………………………………………41 4.3. PERSONAL INTERVIEWS/SURVEYS……………………………………..44
LIST OF FIGURES ………………………………………………………………...….47
REFERENCES AND BIBILIOGRAPHY ………………………………………….…48
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CHAPTER-1-INTRODUCTION 1.1. BACKGROUND 1.2. RESEARCH QUESTION 1.3. SCOPE, OBJECTIVES AND NEED IDENTIFICATION 1.4. METHODOLOGY AND LIMITATIONS
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1.1. BACKGROUND
DISASTER: A disaster is the impact of natural or man-made hazards that negatively affects society or environment. The word disaster's root is from astrology: this implies that when the stars are in a bad position, a bad event will happen. Disasters occur when hazards strike in vulnerable areas. Hazards that occur in areas with low vulnerability do not result in a disaster; as is the case in uninhabited regions. It is often argued that all disasters are man-made, because human actions before the strike of the hazard can prevent it developing into a disaster. Hazards are routinely divided into natural or man-made, although complex disasters, where there is no single root cause, are more common in developing countries. A specific disaster may spawn a secondary disaster that increases the impact. A classic example is an earthquake that causes a tsunami, resulting in coastal flooding. What is Disaster? Disaster is a sudden, calamitous event bringing great damage, loss, destruction and devastation to life and property. The damage caused by disasters is immeasurable and varies with the geographical location, climate and the type of the earth surface/degree of vulnerability. This influences the mental, socioeconomic, political and cultural state of the affected area. Generally, disaster has the following effects in the concerned areas: 1. It completely disrupts the normal day to day life. 2. It negatively influences the emergency systems. 3. Normal needs and processes like food, shelter, health, etc. are affected and deteriorate depending on the intensity and severity of the disaster. Cyclones have a major detrimental impact on the economy of the coastal region of INDIA especially shorelines adjacent to the Bay of Bengal. Cyclones are endemic to the regions of Northern Orissa, Andhra Pradesh, Bengal and certain regions of Tamil Nadu.
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The impact of cyclones is directly felt by the building and a number of deaths which occur during cyclone occur due to building failure. This study stems from a personal experience invading a firsthand exposure to the wrath of cyclones which involved a dramatic scene where in my own out house which was a temporary structure got completely damaged and led to a huge economic loss. The incident mentioned raised a concern regarding the architecture measure which could be in-corporated in order to reduce the impact of cyclones on buildings.
1.2. RESEARCH QUESTION What are the architectural measures that should be adopted to limit the detrimental impact of CYCLONES on buildings in the INDIAN context? According to the research question this topic is chosen as because there were no such pre mitigation measures for cyclone disaster, so here in this study we go through some pre mitigation measures and post mitigation measures taken by the governments in India and other countries, and suggesting the adoptable design techniques for Indian context which were followed by the other countries.
1.3. SCOPE,OBJECTIVES AND NEED IDENTIFICATION SCOPE: The research deals with the case studies and the construction principles and the design techniques involved in the construction industry which can be adoptable to indian context. OBJECTIVES: In this research the main concept and conclusion is to derive the basic and sufficient principles that can be executed into the construction industry where several strategies and methods are available but there is a severe lag of enforcement.
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NEED IDENTIFICATION:
About 5700 Km. of the country‟s coast of 7516 Km exposed to severe cyclones.
Area prone to cyclones is 8.5% of the total area of the country.
Average no. of cyclones forming in the Bay of Bengal and Arabian Sea is 5-6 of which 2-3 cross the Indian Coast every year.
East Coast is more prone than West Coast, the ratio being 4:1.
Super Cyclone of Orissa Oct., 1999 was severe followed by several instances of cyclones including Cyclone Aila in 2009 and Cyclone Laila 2011"
DISASTERS IN ANDHRA PRADESH
CYCLONES AND FLOODS Cyclones are intense low pressure areas, from the center of which pressure increases outwards. The amount of the pressure drop in the center and the rate at which it increases outwards gives the intensity of the cyclones and the strength of winds. These are very strong winds circulating around it in anticlockwise direction in the Northern Hemisphere and in clockwise direction in the Southern Hemisphere.
There were no such bylaws and measures taken or given by the government for constructing a building in a disaster zone mainly in a CYCLONE PRONE AREAS even though the damage and property loss is very high . So there should be some rules and regulations provided for making a building to resist to cyclones. these include the design techiniques and construction measures .
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1.4. METHODOLOGY AND LIMITATIONS The most Affected areas due to CYCLONES are of all time periods 1. North Orissa, and West Bengal coasts. 2. Andhra Pradesh coast line. 3. Tamil Nadu coastal line. State Government Cyclone Related Initiatives Flood Watch broad functions ANDHRA PRADESH Long Term Initiatives Flood Forecasting System Case studies Personal interviews Design techniques followed in other countries Design techniques which are adoptable for the Indian context
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CHAPTER - 2 - LITERATURE SURVEY 2.1. WHAT ARE CYCLONES? 2.2. IMPACT OF CYCLONES 2.2.1. ON LIFE (HUMAN/ANIMAL/NATURE) 2.2.2. BUILDINGS 2.3. MITIGATION MEASURES IN INDIA AND OUT SIDE INDIA
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2.1. WHAT ARE CYCLONES? Natural Disasters: Cyclones “Cyclones are huge revolving storms caused by winds blowing around a central area of low atmospheric pressure. In the northern hemisphere, cyclones are called hurricanes or typhoons and their winds blow in an anti-clockwise circle. In the southern hemisphere, these tropical storms are known as cyclones, whose winds blow in a clockwise circle.” (Faridi, 2008)
How do Cyclones occur? Cyclones develop over warm seas near the Equator. Air heated by the sun rises very swiftly, which creates areas of very low pressure. As the warm air rises, it becomes loaded with moisture which condenses into massive thunderclouds. Cool air rushes in to fill the void that is left, but because of the constant turning of the Earth on its axis, the air is bent inwards and then spirals upwards with great force. The swirling winds rotate faster and faster, forming a huge circle which can be up to 2,000 km across. At the center of the storm is a calm, cloudless area called the eye, where there is no rain, and the winds are fairly light. As the cyclone builds up it begins to move. It is sustained by a steady flow of warm, moist air. The strongest winds and heaviest rains are found in the towering clouds which merge into a wall about 20-30 km from the storm‟s center. Winds around the eye can reach speeds of up to 200 km/h, and a fully developed cyclone pumps out about two million tonns of air per second. This results in more rain being released in a day than falls in a year in a city like London. (Faridi, 2008)
When and where do Cyclones occur? Cyclones begin in tropical regions, such as northern Australia, South-East Asia and many Pacific islands. They sometimes drift into the temperate coastal areas, threatening more heavily populated regions to the South. Northern Australia has about four or five tropical cyclones every year during the summertime wet season. For a cyclone to develop, the sea surface must have a temperature of at least 26ºC.
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Why do Cyclones occur? When warm air rises from the seas and condenses into clouds, massive amounts of heat are released. The result of this mixture of heat and moisture is often a collection of thunderstorms, from which a tropical storm can develop. The trigger for most Atlantic hurricanes is an easterly wave, a band of low pressure moving westwards, which may have begun as an African thunderstorm. Vigorous thunderstorms and high winds combine to create a cluster of thunderstorms which can become the seedling for a tropical storm. Typhoons in the Far East and Cyclones in the Indian Ocean often develop from a thunderstorm in the equatorial trough. During the hurricane season,the Coriolis effect of the Earthâ€&#x;s rotation starts the winds in the thunderstorm spinning in a circular motion.
Cyclone Danger Cyclones create several dangers for people living around tropical areas. The most destructive force of a cyclone comes from the fierce winds. These winds are strong enough to easily topple fences, sheds, trees, power poles and caravans, while hurling helpless people through the air. Many people are killed when the cycloneâ€&#x;s winds cause buildings to collapse and houses to completely blow away. A cyclone typically churns up the sea, causing giant waves and surges of water known as storm surges. The water of a storm surge rushes inland with deadly power, flooding low-lying coastal areas. The rains from cyclones are also heavy enough to cause serious flooding, especially along river areas. Long after a cyclone has passed, road and rail transport can still be blocked by floodwaters. Safe lighting of homes and proper refrigeration of food may be impossible because of failing power supplies. Water often becomes contaminated from dead animals or rotting food, and people are threatened with diseases like gastroenteritis. (Faridi, 2008)
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2.2. IMPACT OF CYCLONES Cyclones & their Impact in India 1. History of Cyclones in India: 1.2. Although cyclones affect the entire coast of India, the East Coast is more prone compared to the West Coast. An analysis of the frequencies of cyclones on the East and West coasts of India during 1891-2000 show that nearly 308 cyclones (out of which 103 were severe) affected the East Coast. During the same period 48 tropical cyclones crossed the West Coast, of which 24 were severe cyclonic storms. Out of the cyclones that develop in the Bay of Bengal, over 58 percent approach and cross the east coast in October and November. Only 25 percent of the cyclones that develop over the Arabian Sea approach the west coast. In the pre-monsoon season, corresponding figures are 25 percent over the Arabian Sea and 30 percent over the Bay of Bengal. (Authority, 2010)
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Number of Cyclones Crossing Various coastal Districts of East and West Coast of India during 1891- 2000 WEST COAST Station Coastal Districts
State Kerala (3)
Karnataka (2)
Maharastra (13)
EAST COAST No. of Cyclonic storms
State
Malappuram Kozikode Kannur
1 1 1
W.Bengal 24 - Parganas (69) (North & South) Midnapur
Dakshina Kannada Uttar Kannada
1
Orissa (98)
Sindhu durg Ratnagiri Mumbai Thane
1 3 3 3 4
Andhra Pradesh (79)
2 Goa
Gujarat (28)
Station Coastal Districts
Surat kaira Bhavnagar Amroli Junngarh Jamnagar Kutch
1 1 4 4 7 6 5
Tamil Nadu (62)
No. of Cyclonic storms 35 34
Balasore Cuttack Puri Ganjam
32 32 19 15
Srikakulam Visakhapatnam East Godavari West Godavari Krishna Guntur Prakasam Nellore
14 9 8 5 15 5 7 16
Chennai Cuddalore Puducherry Southarcot Tanjavur Pudukkottai Ramnathpuram Tirunelveli Kanyakumari
18 7 8 5 12 5 3 2 2
(Authority, 2010)
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Historical records of 11 most devastating cyclones which formed in the Arabian Sea and made landfall on the West coast of India Historical records of 12 most devastating cyclones, which formed in the Bay of Bengal and made landfall on the East coast of India
A cyclone causes heavy floods.
It uproots electricity supply and telecommunication lines. Power supply shuts down and telephones stop functioning.
Road and rail movements come to halt because floods damage rail tracks and breach roads. Rail movements are also disrupted because of communication failure.
The inclement weather conditions also disrupt Air services. Seaports stop work due to high winds, heavy rains and poor visibility. Sometimes ships overturn or are washed ashore. The high speed winds bends and plucks out trees and plants.
A cyclone tears away wall sidings and blows off roofs of houses.
Houses collapse and people are rendered homeless. In villages kachha houses get blown away. The speeding winds cause loose metal and wooden sheets to fly turning them to potential killers. Broken glass pieces can cause serious injuries.
The floodwaters can take time to recede.
The floodwaters can turn the fields salty.
Bridges, dams and embankments suffer serious damages.
Floods wash away human beings and animals and make water unfit for drinking. There can be outbreak of diseases like Cholera, Jaundice or Viral fever due to intake of impure water. Water gets contaminated because of floating corpses of animals and human beings and mixing of sewage stored food supplies, get damaged. (Reliefeffort, 1999)
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2. Recent Cyclone in Orissa in October 1999: 2.1. A very severe cyclonic storm and a Super Cyclone hit the Orissa coast in quick succession in October 1999. Before the people could recover from the impact of the first cyclone on 17th October, 1999, a Super Cyclone struck Orissa coast during October 29-30, 1999. These cyclones left a trail of death and destruction and devastated 14 districts in the State. About 8960 persons lost their lives, 4,50,000 cattle perished, about 2 million houses were damaged, about 90 million trees were uprooted and 1.8 million ha. paddy and 33,000 ha. Non-paddy cultivated land was affected. Infrastructure facilities were severely damaged. Saline inundation left most of the drinking water sources polluted and dysfunctional. The loss estimated by Orissa Government was about Rs. 62 billion, which did not include the loss to the Central Government properties like Railways, Telecommunication etc. According to other estimates, the total financial loss was over Rs. 100 billion making it the worst cyclone related disaster of rare occurrence in the recent past in India. 3. Special nature of the problem 3.1. Though the frequency of Tropical Cyclones in the North Indian Ocean (NIO) are the least in the world (7% of the global total), their impact on the coasts bordering the North Bay of Bengal (North of 150 N latitude) in India as well as in the Bangladesh are extremely disastrous. The problem can be fathomed from the fact that during the past two and a half centuries, 20 out of 23 major cyclone disasters (with human loss of life 10,000 or more and not considering the damages) in the world have occurred over the Indian Subcontinent (India and Bangladesh). One of the major reasons for this is the serious storm tide problem in these coasts. A tropical cyclone of specific intensity when it strikes the east coast of India and Bangladesh, usually produces a higher storm surge compared to that when such a cyclone strikes elsewhere in the world. This is because of the special nature of the coastline, the shallow coastal ocean topography and the characteristics of tide in the North Bay of Bengal region. Further the high density of population, low awareness of the community about cyclones and their risks, inadequate response and preparedness add to the severity of the problem. 3.2.There are 13 Coastal States and UTs in the country, with about 84 coastal Page | 12
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districts affected by tropical cyclones. Four States (Tamil Nadu, Andhra Pradesh, Orissa and West Bengal) and one UT (Puducherry) on the East Coast and one State (Gujarat) on the West Coast are the States that are more vulnerable to cyclone disasters. (ISSD, 2012) 4. Vulnerability to Cyclones: Cyclones are natural events, which can neither be wished away nor prevented. What actually makes these hazards turn in to disasters is the vulnerability of the people and their means of livelihood and the fragility of infrastructure. The Indian Sub-continent is the worst affected part in the world as far as loss of lives is concerned though more severe cyclones do occur in other parts of the world and financial losses are much more elsewhere. This could primarily be attributed to the special nature of the problem discussed above and the vulnerability of the people. High population density, comparatively better employment opportunities and economic compulsions force people to occupy, areas, which are susceptible to cyclones, saline ingress and flooding. Inadequacy of infrastructure adds to their vulnerability. Traditional coping mechanisms have been the mainstay for these people to counter hazards, but during major disasters these coping mechanisms are found wanting. Though communities have a natural tendency to face hazards by joining hands, they usually fail to generate the desired synergy because of unsystematic and ad hoc approaches. On many occasions people are not even aware of the risks involved. The frequent disasters nullify the development of several years and turn the clock back for these vulnerable families. (Authority, 2010) 5. Impact on the Coastal Eco-System: “Coastal ecosystem� includes estuaries and coastal waters and lands located at the lower end of drainage basins, where streams and river systems meet the sea and are mixed by tides. The coastal ecosystem includes saline, brackish (mixed saline and fresh) and fresh waters, as well as coastlines and the adjacent lands. All these water and landforms interact as integrated ecological units. Shore-lands, dunes, sandbars, offshore islands, headlands, and freshwater wetlands within estuarine drainages are included in the definition since these interrelated features are crucial
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to coastal fish and wildlife and their habitats. Mangroves are located all along estuarine areas, deltas, tidal creeks, mud flats, salt marshes and extend over 4871 sq. km (about 7% of world‟s mangrove areas). Impact of global warming- induced sea level rise due to thermal expansion is more pronounced in the Bay of Bengal due to the shallowness of the waters. The entire coastal ecosystem in general and the eastern coast in particular are highly vulnerable due to flat and low terrain, high population density, over exploitation of natural resources, high rate of environmental degradation on account of pollution and non-sustainable development. On many occasions, the livelihood requirements of people are detrimental to maintaining the delicate balance of the fragile coastal ecosystem. Degradation of the eco-system not only affects the environment adversely, but also makes the people living in the coastal areas more vulnerable. (Authority, 2010)
CYCLONES & THEIR IMPACT OUT OF INDIA
The main effects of tropical cyclones include heavy rain, strong wind, large storm surges at landfall, and tornadoes. The destruction from a tropical cyclone depends mainly on its intensity, its size, and its location. Tropical cyclones act to remove forest canopy as well as change the landscape near coastal areas, by moving and reshaping sand dunes and causing extensive erosion along the coast. Even well inland, heavy rainfall can lead to mudslides and landslides in mountainous areas. Their effects can be sensed over time by studying the concentration of the Oxygen18 isotope within caves within the vicinity of cyclones' paths. After the cyclone has passed, devastation often continues. Standing water can cause the spread of disease, and transportation or communications infrastructure may have been destroyed, hampering clean-up and rescue efforts. Nearly two million people have died globally due to tropical cyclones. Despite their devastating effects, tropical cyclones are also beneficial, by potentially bringing rain to dry areas and moving heat from the tropics poleward. Out at sea, ships take advantage of their known characteristics by navigating through their weaker, western half. (Kantardžića, 1996)
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At least 77 people in southeastern Africa have been killed and more are still missing as Tropical Cyclone Irina sweeps through the region.The storm struck northern Madagascar more than two weeks ago and has slowly tracked down the west of the country. Torrential rain from the system hit the whole of the island, leading to the deaths of 65 people, weather officials said on Monday. The majority of the deaths occurred in the southeastern district of Ifanadiana.The storm has also affected southern areas of Mozambique and eastern South Africa.Five fishermen were killed in the seas off Mozambique‟s port city of Beira on Saturday. Authorities on Monday were still cautioning fishermen not to venture out.Three other people in the southern province of Gaza were killed when a tree fell on their house and the roof collapsed. A further four people are reported to have died in South Africa. The city of Durban was lashed by waves up to three metres high as the storm approached, and ships were ordered to remain in the port.Tropical storms in the southwest Indian Ocean are responsible for approximately 80 deaths every seasonOn average three tropical cyclones hit Madagascar every year, and this season has now equalled that average. Less than two weeks before Irina, Tropical Cyclone Giovanna caused flooding and led to the deaths of 35 people.Tropical Cyclone Giovanna was a far more intense storm, the equivalent of a category 4 hurricane when it made landfall, but ample warnings kept the death toll comparatively low. It is far more unusual for southern Mozambique and South Africa to feel the impact of a tropical storm. In January, southern Mozambique was hit by Tropical Cyclone Dando, but that was the first storm to hit the region since 1984, when Tropical Cyclone Domoina made impact.Tropical Cyclone Domoina led to the death of 214 lives, and is the most deadly storm in recent decades.The tropical storm season in the southwest Indian Ocean runs between the months of November and February, but there is a chance that this storm season has not yet ended, with Tropical Cyclone Irina threatening to buckle back around, and head towards the coast of southeast Africa once more.Locals there would be wise to keep a very close eye on this erratic storm. (Kantardžića, 1996)
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2.2.1.) ON LIFE ( HUMAN/ANIMAL/NATURE) The major impact of cyclones can be broadly categorized as below: 1. Loss of lives, injuries and other health consequences such as epidemics, and post traumatic stress disorders. 2. Loss of habitat. 3. Loss of cattle and damage to crops and agricultural fields. 4. Damage to public utilities. 5. Disturbance and damage to the ecosystem.
2.2.2.) EFFECTS OF CYCLONES ON BUILDINGS? As a consequence of the storm surge and high wind speed following types of damage are commonly seen:
Uprooting of trees which disrupt transportation and relief supply missions.
Damage to signposts, electric poles and transmission line towers.
Damage to improperly attached windows or window frames.
Damage to roof/lintel projections.
Failure of improperly attached or constructed parapets.
Overturning failures of compound walls of various types.
Failure of roofing elements and walls along the gable ends particularly due to high internal pressures.
Failure of large industrial buildings with lightweight roof coverings and long/tall walls due to combination of internal & external pressures.
Brittle failure of asbestos.
Punching and blowing off of corrugated iron roofing sheets attached to steel trusses
How High Winds Damage Buildings Contrary to popular belief, few houses are blown over. Instead, they are pulled apart by winds moving swiftly around and over the building. This lowers the pressure on the outside and creates suction on the walls and roof, effectively causing the equivalent of an explosion. Whether or not a building will be able to resist the effects of wind is dependent not so much upon the materials that are used but the manner in which they are used. It is a common belief that heavier buildings, such as those made of concrete block, are Page | 16
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safer. While it is true that a well-built and properly-engineered masonry house offers a better margin of safety than other types of buildings, safe housing can be and has been provided by a variety of other materials including wood and many others. 3. Catastrophic Failures 3.1 Foundations The uplift forces from cyclone winds can sometimes pull buildings completely out of the ground. In contrast to designing for gravity loads, the lighter the building the larger (or heavier) the foundation needs to be in cyclone resistant design. Ignoring this precept has led to some dramatic failure of long-span, steel-framed warehouses.
Foundation (too small for light weight building) pulled completely out of Ground.
Figure 1 , CRBA ,Ankush Agarwal
IMAGE SOURCE: CYCLONE RESISTANT ARCHITECTURE BY ANKUSH
3.2 Steel Frames A common misconception is that the loss of cladding relieves the loads from building frameworks. There are several circumstances where the opposite is the case and where the wind loads on the structural frame increases substantially with the loss of cladding. Usually the weakness in steel frames is in the connections. Thus economising on minor tems (bolts) has led to the overall failure of the major items (columns, beams and rafters). 3.3 Masonry Houses These are usually regarded as being safe in cyclones.There
Figure 2, CBRA , Ankush Agrawal
are countless examples where the loss of roofs has triggered the total destruction of un-reinforced masonry walls.
Total loss of unreinforced concrete blockwalls and destruction of einforcedconcrete supports
3.4 Timber Houses The key to safe construction of timber houses is the connection details. The inherent vulnerability of light-weight timber houses coupled with poor connections is a dangerouscombination which has often led to disaster.
Figure 3,, CBRA , Ankush Agrawal Destruction of expensive timber Framed residence (Bahamas)
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3.5 Reinforced Concrete Frames The design of reinforced concrete frames is usually controlled by the seismic hazard. In countries where this is not an issue care still needs to be exercised to ensure that the concrete frames can accommodate the wind forces. There have been a few isolated examples where, ignoring this, has led to disaster.
4. Component Failures 4.1 Roof Sheeting This is perhaps the commonest area of failure in cyclones. The causes are usually inadequate fastening devices,
Figure 4, CBRA , Ankush Agrawal
inadequate sheet thickness and insufficient frequencies
Loss of corrugated, metal, roof sheets
of fasteners in the known areas of greater wind suction. 4.2 Roof Tiles These were thought to have low vulnerability in storms but past cyclones have exposed the problem of unsatisfactory installation practices. 4.3 Rafters Of particular interest in recent cyclones was the longitudinal splitting of rafters with the top halves disappearing and leaving the bottom halves in place. The splitting would propagate from holes drilled horizontally
Figure 5, CBRA , Ankush Agrawal Longitudinal splitting of timber rafters
through the rafters to receive holding-down straps. 4.4 Windows and Doors After roof sheeting, these are the components most frequently damaged in cyclones. Of course, glass would Always be vulnerable to flying objects. The other area of vulnerability for windows and doors is the hardware - Latches, bolts and hinges. 4.5 Walls It is not uncommon for un-reinforced masonry to fail in severe cyclones. Cantilevered parapets are most at risk. But so are walls braced by ring beams and columns have remained safe. (Agrawal, 2007)
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5. Damaging Effects of Cyclone on Houses 5.1 Due to the high wind pressure and improper connection of the house to the footings it can be blown away. 5.2 Roofing materials not anchored can be blown away. 5.3 Light weight verandah roofs are more susceptible to damage due to high wind speed.
Figure 6,CBRA , Ankush Agrawal
5.4 When cyclones are accompanied with heavy rain for along duration, the buildings can be damaged due toflooding also. Building contents are spoiled due to rain when roofing sheets fly away. 6. Design Wind Speed and Pressures The basic wind speed is reduced or enchanced for design of buildings and structures due to following factors: (i) The risk level of the structure measured in terms of adopted return period and life of structures. (ii) Terrain roughness determined by the surrounding buildings or trees and, height about size of the structure. (iii) Local topography like hills, valleys, cliffs, or ridges, etc. Thus general basic wind speed being same in a given zone, structures in different site conditions could have appreciable modification and must be considered in determining design wind velocity as per IS:875 (Part 3)– 1987. The value of wind pressure actually to be considered on various elements depends on (i) Aerodynamics of flow around buildings.(ii) The windward vertical faces being subjected to pressure.(iii) The leeward and lateral faces getting suction effects and (iv) The sloping roofs getting pressures or suction effects depending on the slope. The projecting window shades, roof projections at eave levels are subjected to uplift pressures. These factors play an important role in detemining the vulnerability of given building types in given wind speed zones. (Agrawal, 2007) Page | 19
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2.3. MITIGATION MEASURES IN INDIA AND OUT SIDE INDIA
Disaster Mitigation Measures Taken in INDIA The Ministry of Home Affairs , Government of India , is at present the nodal agency responsible for disaster mitigation actions . In addition to this central government involvement, recently State level disaster management plans have been put in place to not only coordinate the relief operations in case of emergency but take appropriate pro-active measures to prevent sufferings and huge economic losses in future . The Gujarat state has set up a Gujarat State Disaster Management Agency . A similar organisation has been set up by Orissa . A part from such formal arrangements as exemplified above , substantial effort has been going on , concerning the different components of the problem , taken up separately by a number of institutions , government, departments , NGOâ€&#x;s etc. through which significant process has been made towards mitigation . The status of the important components of Disaster Mitigation and related needs is addressed briefly below
1.Hazard Evaluation a)Mapping the areas affected by each major hazard b)Historical and pre-historical events c)Set up of early warning systems d)Quantification of the hazards e)Communication with emergency management authorities f)Scenario Generation of Cyclonic Disasters
Cyclone Risk Mitigation and Preparedness Framework Based on the lessons learnt from the cyclones around the world and the advances made in various related sciences and disciplines on the subject a cyclone risk mitigation and preparedness framework can be presented in the shape of the following diagram:
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PREVENTION AND MITIGATION MEASURES RISK ASSESSMENT The evaluation of risks of tropical cyclones should be undertaken and illustrated in a hazard map. The following information may be used to estimate the probability of cyclones which may strike a country. Analysis of climatological records to determine how often cyclones have struck, their intensity and locations;History of winds speeds, frequencies of flooding, height location or storm surges;Information about 50-100 years cyclone activity. LAND USE CONTROL This is designed to control land use so that the least critical facilities are placed in most vulnerable areas. Policies regarding future development may regulate land use Page | 21
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and enforce building codes for areas vulnerable to the effects of tropical cyclones. For example, in coastal areas, regulation can stipulate maximum building heights, types of land and occupant density. Another option includes the purchase of vulnerable areas by government for use of parks, sports facilities and open grazing land. FLOOD PLAIN MANAGEMENT A master plan for flood plain management should be developed to protect critical assets from flash, riverine and coastal flooding. REDUCING VULNERABILITY OF STRUCTURES AND INFRASTRUCTURES New buildings should be designed to be wind and water resistant. Design standards are usually contained in building codes. Communication and utility lines should be located away from the coastal area or installed underground;Improvement of building sites by raising the ground level to protect against flood and storm surges. Protective river embankments, levees and coastal dikes should be regularly inspected for breaches due to erosion and opportunities taken to plant mangroves to reduce breaking wave energy;Improved vegetation cover. This helps to reduce the impact of soil erosion and landslides and facilitates the absorption of rainfall to reduce flooding. STRUCTURAL AND NON STRUCTURAL MITIGATION Given the nature of the cyclonic hazards, it shall not be possible to prevent the risks of cyclone however advanced the country may be socially or economically, as has been well demonstrated during the aftermath of hurricane Katrina in the USA. On the contrary there are indications that the hazards of cyclone would increase due to the effects of global warming and the resultant climate changes. As the ocean surface temperature rises probability of atmospheric depressions on tropical seas would increase. Similarly as the glacial melts raises the level of ocean the impact of storm surges would be more severe and many sea wall or embankment modeling done in the past may undergo revisions necessitating redefinition of the design parameters of such constructions.
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In the face of increasing menace of cyclonic hazards, mitigation would remain the key and the most effective strategy to reduce the risks of cyclone. Every country and community has to decide its own mitigation strategy according to its own risks, resources and capabilities. Broadly such strategies would be: structural and nonstructural. Structural mitigation measures generally refer to capital investment on physical constructions or other development works, which include engineering measures and construction of hazardresistant and protective structures and other protective infrastructure. Non-structural measures refer to awareness and education, policies techno-legal systems and practices, training, capacity development etc. SEA WALL AND EMBANKMENTS Among the structural mitigation measures sea walls and saline water embankments are probably the most effective and capital intensive investment to mitigate the risks of cyclones. A seawall is a coastal defense constructed usually of reinforced concrete on the inland part of a coast to prevent the ingress of storm surges arising out of cyclones. Sometimes the sea wall is constructed with a multiple purpose of reclaiming low lying land or preventing coastal erosion. The height of sea walls is determined according to the maximum observed height of storm surges which may be as high as 10 meters. Therefore sea walls are usually massive structures which can be built only with a heavy investment. Maintenance of such structures further requires recurrent expenditure. Hence sea walls along the entire coast are never a practicable solution to prevent or mitigate storm surges, but such walls are recommended when valuable assets like a city or a harbor is to be protected. Sea walls can be vertical, sloping or curved. Modern concrete sea walls tend to be curved to deflect the wave energy back out to sea, reducing the force. There are instances of many sea walls which were constructed after devastating cyclones and which successfully prevented such disasters. The most important is the 12 Km long and 17 ft high seawall constructed in Texas after the Galveston Hurricane of 1900 which killed 8000 people. The seawall has never been overtopped by a storm surge from a hurricane, although maintenance of the wall has been beset with various engineering problems. The Gold Coast seawall in Australia was laid along the urban sections of the Gold Coast coastline following 11 cyclones in 1967. The massive stone seawall in Pondicherry constructed and maintained by the French engineers Page | 23
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kept the historic city center dry even though tsunami waves of December 2004 had driven water 24 feet above the normal hightide mark. Similarly 3.5 meter high sea wall in Maldives saved the city of Male from the tsunami. Such success stories are available from many coastal cities. There are also instances where absence of such protective structures near the beaches and resorts and breaches in sea walls near the cities and towns resulted in severe damages to life and property. If sea walls are essential to protect coastal cities and harbors, saline water embankments are recommended to protect rural settlements and to prevent saline water ingress into agricultural and horticultural land. Such embankments are usually a ridge built with earth or rock to contain the storm surges. Cost benefit calculations usually do not permit very high specifications for such constructions and therefore effectiveness of such embankments in preventing or mitigating the impacts of cyclones have been rather limited. Further, saline embankments have the potential to kill the mangroves due to chocking of saline water. Therefore such embankments should be constructed in limited areas where vegetative protection would not be adequate to prevent the ingress of saline water into habitations.
CYCLONE SHELTER A large number of people in the coastal areas live in thatched houses which cannot withstand the high velocity of wind and storm surges resulting in extensive damages of such houses and deaths and injuries of a large number of poor people. The high rates of casualties in cyclones in Bangladesh and India are primarily due to unsafe buildings in the coastal areas. The poor economic conditions of the people may not permit them to rebuild their houses as per the cyclone resistant designs and specifications. Therefore, community cyclone shelters constructed at appropriate places within the easy access of the habitations of the vulnerable communities can provide an immediate protection from deaths and injuries due to the collapse of houses. Such shelters are usually built on pillars above the danger level of storm surges/inundation, are specious enough to accommodate a few hundred people of the neighboring hamlets and provide provisions of drinking water, sanitation, kitchen, etc. During the normal season such shelters can be utilized as schools, dispensaries or other community purposes. A large Number of such cyclone shelters were built in the coastal areas of Bangladesh and eastern and south India, which provided immediate shelters to the vulnerable communities. Drastic reduction in the number of Page | 24
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deaths and injuries in the cyclones during the past 5-6 years can be partly attributed to these shelters. Therefore, the governments have placed a very high priority on the construction of such shelters in areas which have hitherto not been covered.
CYCLONE RESISTANT HOUSING & INFRASTRUCTURE Super cyclones with wind velocity of 250 km per hour and above have caused damages to even engineered structures at many places around the world. This was largely due to the absence of appropriate design criteria for construction of buildings and infrastructure which can withstand the pressures of such strong winds. Bureau of Standards of various countries have developed revised design norms which are followed for new constructions. However, the compliance standards of such norms have not been very effective largely due to inadequacies of properly trained engineers and masons who can supervise and raise such constructions. The problem is further compounded by a week and ineffective system of enforcement of the guidelines. The problem is even more complex for the large number of existing structures that have already been constructed without adherence to the revised norms. Such buildings can only be retrofitted with an additional cost which the house owners find reluctant to invest. Various advanced countries have passed legislations which has made retrofitting mandatory. In the developing countries the focus is confined more to strengthening the lifeline buildings which would play a critical role during emergency operations such as hospitals, emergency operation centers, police control rooms etc, leaving other unsafe structures and habitations as „acceptable risksâ€&#x;, for which adequate preparedness measures should be developed. (Dr.N.M. Bhandri,Dr.Prem Krishna,Dr.Krishen Kumar, 2009)
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CHAPTER- 3 - COCLONIC REPORTS 3.1. AROUND THE WORLD IN PAST 4 CENTURIES 3.2. CASE STUDIES FROM INDIA 3.2.1. PRIMARY
: OWN EXPERIENCE (AILA cyclone)
3.3. 2. SECONDARY : ORISSA - 1999
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3.1. AROUND THE WORLD IN PAST 4 CENTURIES Historical records of Severe Cyclones which formed in theBay of Bengal and made landfall at the eastern coast of India during the period from 19701999. September 20-25. 1971 Crossed South Orissa coast near Gopalpur on September 22.Caused considerable damage to crops and houses due to flood and heavy rain at Vamsadhura village in Srikakulum and koraput districts. September 27 -October 1,1971 Crossed West Bengal coast near Sundarban . Continued its movement towards NW, weakened into a low over Bihar State on October 1.60 People died and thousands of houses were collapsed in West Bengal. October 26-30,1971 Crossed Orissa coast near Para-dip early in the morning of October 30.Maximum wind speed recorded was 150-170KMPH (81-92 kt).Lowest Pressure recorded 966.00 hPa. near the centre of the storm. 10,000 People died and more than one million people rendered homeless.50, 000 Cattle heads perished, 8,00,000 Houses damaged. November 8-12, 1977 Crossed Tamilnadu coast within 10 km to south of Nagapattinam early in the morning of 12th around 2230 UTC of 11th. Weakened into a cyclonic storm by that evening over interior parts of Tamilnadu and emerged into Laccadives off North Kerala coast on the morning of 13th as a deep depression.Maximum wind recorded about 120 KMPH ( 65 kt) on 12th mroning at Thanjavur , Tiruchirapalli and Podukottai.560 people died and 10 lakh people rendered homeless. 23,000 Cattle heads perished. Total damage to private and public property estemated to be Rs. 155 crores.
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November 14-19 ,1977 Crossed near Chirala in A.P at 1200 UTC on 19th Nov. and weakened into a low on the evening of 20th. It dissipated over Southeast M.P and adjoining Orissa by 21st evening.Maximum wind speed recorded by the ship Jagatswami recorded at 1030 Utc on 17th was 193 KMPH( 104kt)Loss of human lives reported as 10,000.27,000 Cattle head perished. Damage to the crops and other property was estimated to be around 350 crores November 19-24 , 1978 Crossed between Kilakkarai and Rochemary and Ramanatharam District of Tamil Nadu.on 24th.evening as a severe storm and emerged into the Arabian Sea off Kerala coast as a deep depression on 25th morning.Batticola of Sri Lanka reported maximum wind speed northerly 145 KMPH (78 kt).In India 5,000 huts damaged and totasl damage estimated to be around Rs. 5 crores. In SriLanka ,915 people died and one million people affected One lakh Houses were damaged in SriLanka. October 9-14.1984 CrossedNorth Orissa coast near Chandbali in theforenoon of 14th This system caused some damage in Cuttack and Balasore districts of Orissa and Midnapore districts of West Bengal. November 27-30 , 1984 Crossed south Tamilnadu coast near Nagapattinam in the afternoon of December 1 near Karaikal.About 35,000 people were affected in East Thanjavur and South Aroot districts of Tamilnadu.50,000 acres of lnad was submerged in Thanjvur districts. Bay of Bengal, India (1737) Over 300,000 were drowned and 20,000 ships smashed. Four islands were buried beneath forty-foot-high waves, which washed out thousands of coastal huts and dwellings. This typhoon was the second most deadly in history.
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Coromandel Coast, India (1787) A southeastern India cyclone caused storm waves to wash over low-lying areas from Nagappatinam to Kavali. 10,000 people drowned and 100,000 more cattle were lost, as the waves sometimes swept as much as 20 miles inland. Bengal, India (1876) A tropical cyclone struck the coast of Bengal in present day Bangladesh near the Meghna River mouth. Waters rose twenty feet above normal, swallowing the islands near Chittagong. About 100,000 died immediately, and another 100,000 died from starvation due to crop loss. Bombay, India (1882, June 6) An Arabian Sea cyclone created high waves at Bombay harbor. 100,000 people in and around the city perished. Bengal coast, India (1942, October 16) A cyclone takes 35,000 lives south of Calcutta. The storm, originating in the Bay of Bengal, happened during wartime censorship, so some reports claim only 11,000 died. Andhra Pradesh, India (1977, November 19-20) A cyclone with 95 mph winds pushed huge waves from the Bay of Bengal over the coastal areas north of Madras. Upwards of a dozen villages and their residents were swept away, making the death toll as many as 10,000 people. Another tropical storm hit five days earlier, taking several thousand lives in the Tamil Nadu State. (ISSD, 2012) Japan (Vera) (1959, September 26-27) Typhoon Vera was the worst in Japanese history, killing 4,464 residents of Honshu Island and injuring an additional 40,000. 40,000 homes were also destroyed, making 1.5 million people homeless. The regional railway system was cut in 827 different places. In addition, another typhoon occurred ten days earlier, killing 2,000 Japanese and Korean citizens. Atlantic states, USA (Hazel) (1954, October 5-18) The third major hurricane of that year was Hurricane Hazel, a severe storm that struck an area from the southeastern Caribbean to Ontario, Canada. Between 600 Page | 29
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and 1,200 people were killed, while property damage was estimated at $350 million. The storm began near Grenada on October 3 and moved north, turning into a full hurricane with 115-mile-per-hour winds by October 12. On October 14, the storm hit the Bahamas and then moved west to hit Cape Fear, North Carolina with 150 mph winds. Over 1,000 houses were destroyed along the coast. Only 3 of Garden City, South Carolina’s 275 buildings were left undamaged. At Carolina Beach, North Carolina, 1,365 buildings were damaged and 475 completely destroyed. 100,000 cubit feet of sand were deposited in the streets. Damage along the coast totaled more than $60 million, but only 19 perished thanks to well-established warning systems. Hazel, instead of losing power, intensified and continued to move over the Mid-Atlantic states toward Toronto. Record wind speeds were measured as it cut across New York, leaving 95 dead and $252 million property damage in the U.S. Hurricane Hazel hit Toronto at 11 p.m. on October 15, releasing 7 inches of rain in a single day and causing severe floods. Humber River turned into a violent river. Two weeks after it first began, Hazel finally exhausted its energy over Hudson Bay. Another 78 people were dead and more than $100 million property damage caused in Canada. Galveston, Texas, USA (1915, August 5-25) On August 10, a huge low-pressure storm originating off the Cape Verde Islands crossed the Atlantic and entered the Caribbean Sea between the islands of Guadeloupe and Dominica. The storm then passed westward with winds measuring over 120 miles per hour. Galveston received a twenty-four-hour warning, the same city that was destroyed by hurricane fifteen years previously. The city, however, felt it was ready, having raised and filled an area forty blocks long and twenty-two blocks wide. A $9 million seawall, 16 feet wide and 4 feet higher than any recorded tide, had been built along an 8-mile stretch to protect the harbor. However, even with plenty of prior warning and defensive measures, the hurricane pushed tides 12 feet above normal. 5 feet of water poured into the business area of town, damaged 90% of buildings, caused $50 million in property loss, and drowned 275 citizens. The seawall, however, did much to protect the city from the brunt of the storm and helped Galveston survive. (Govt., 2012)
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Mid-Atlantic States, USA (Agnes) (1972, June 14-23) Hurricane Agnes was the most expensive natural disaster in American history. Originating near Cozumel Island, Hurricane Agnes crossed the Gulf of Mexico and struck the west coast of Florida, heading for the Atlantic. Instead, however, Agnes changed direction and moved north to New York City. Agnes did not have intense winds, but carried billions of tons of water. One June 21, now resembling a tropical rainstorm, brought the heaviest rains in many years to New Jersey, Pennsylvania, and New York. The region suffered the worst flooding in American history. The Susquehanna River in Pennsylvania ran 30 feet above normal. The river at WilkesBarre flowed three feet above the level of control dikes, driving more than 100,000 from their homes. Agnes would go on to flood 4,500 miles of river, 9,000 miles of streams, and cause flood damage in five states, 25 cities, and 142 counties. Over 5,000 square miles were completely submerged and 330,000 people left without homes. Half a million residents suffered some sort of property damage. 122 people lost their lives, while the nation incurred $4.5 billion in immediate property damage. The long-term damage of the storm, relief efforts, economic disruption, employment loss, etc. may never be estimated. As a result of the disaster, many people moved away, dealing a great blow to local industries. Honduras (Fifi) (1974, September 18-20) Hurricane Fifi hit Honduras with heavy rains and winds exceeding 110 mph. Flooding caused extensive life and property loss, taking 5,000 lives and making an addition 60,000 homeless. Choloma was hit hardest, as the hurricane triggered an avalanche of trees, boulders, and waters that killed between 2,000 and 3,000 of the townspeople. The town was also damaged by flash floods. The original avalanche dammed the river that ran through town. However, this dike later burst so the rest of the city was engulfed by onrushing water. Many of the initial survivors were killed and one square mile of town was covered with mud and debris. Half of Cholomaâ€&#x;s population perished. In other places, thousands of acres of banana plantations were flooded and covered with thick mud. The hurricane also hit Belize, southern Mexico, Guatemala, and El Salvador, where 75 drowned in flash flooding. (Acadamy, 2010)
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3.2. CASE STUDIES FROM INDIA 3.2.1. PRIMARY
: OWN EXPERIENCE (LAILA cyclone)
The toll in the cyclone-related incidents rose to 36 on Friday with 12 more deaths reported from Krishna , Guntur , Visakhapatnam, Vizianagaram and Prakasam districts. "Several persons are reported missing from the worst-hit coastal districts. More than 170 houses were completely destroyed and 265 suffered partial damage while 367 livestock perished in the cyclone. Early in the duration of the cyclone, the IMD noted the potential for heavy rainfall and gusty winds along the coast of Andhra Pradesh. The agency advised fishermen to avoid being in open seas. Additionally, the agency contacted state governments in the region to warn of the storm's threat. The weather office has stated that the cyclone will not have an effect on the monsoon season. Cyclone Laila battered Ongole town; it received heavy rain of 320 mm on May 20 and 142 mm on 2009 May 21, and has made rivulets like Gundlakamma, Addavagu and Pothurajukalva swollen. Addanki received the highest rainfall of 522 mm, followed by Maddipadu with 510 mm and Kothapatnam 258 mm in 24 hrs on May 21. The cyclone caused heavy destruction in Prakasam, Krishna and Guntur districts and preliminary reports prepared by the State government put the loss at over Rs 500 crore.According to a BBC report, Cyclone Laila is the worst storm to hit Andhra Pradesh in 14 years.
Figure 7 9,Eenadu, Telugu newspaper
Figure 8
Figure
Personally from my experience we in our place have experienced a severe damage from this cyclone. Many temporary structures like cattle sheds and water pump sheds got torn away because of the cyclone. Not only the temporary structures even the residential areas got affected by the cyclone Page | 32
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2012
: ORISSA – 1999
The 1999 Orissa cyclone, also known as Cyclone 05B, and Paradip cyclone, was the deadliest tropical cyclone in the Indian Ocean since the 1991 Bangladesh cyclone, and deadliest Indian storm since 1971. The Category Five storm made landfall just weeks after a category 4 storm hit the same general area. A tropical depression formed over the Malay Peninsula on October 25. It moved to the northwest and became a tropical storm on October 26. It continued to strengthen into a cyclone on October 27. On October 28, it became a severe cyclone with a peak of 160 mph winds. It hit India the next day as a 155 mph cyclone. It caused the deaths of 15,000 people, and heavy to extreme damage in its path of destruction.
Figure 10Orissa cyclone relief effort
Tens of thousands of families from the coastal districts of Balasore, Bhadrak, Kendrapara, Jagatsinghpur, Puri, and Ganjam were forced to evacuate their homes before the storm's arrival. More than 44,500 people took shelter in twenty three Red Cross cyclone shelters.] Cuttack and Khorda further inland were also severely affected.
Figure 11 , Orissa cyclone relief effort
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The cyclone dumped heavy torrential rain over southeast India, causing record breaking flooding in the low-lying areas. The storm surge was 26 feet (8 meters). struck the coast of Orissa, traveling up to 20 km inland .17,110 km² crops were destroyed, and an additional 90 million trees were either uprooted or had snapped. Approximately 275,000 homes were destroyed, leaving 1.67 million people homeless. Another 19.5 million people were affected by the super cyclone to some degree. A total of 9,803 people officially died from the storm, with 40 others still missing. though it is believed that 15,000 people died.8,119 of those fatalities were from the Jagatsinghpur district. Another 3,312 people were injured. 2,043 out of 5,700, or 36% of the residents of Padmapur perished. The number of domestic animals fatalities was around 2.5 million,though the number of livestock that perished in the cyclone amounted to only 406,000.The high number of domestic animal deaths may have possibly had to do with around 5 million farmers losing their livelihood. The damage across fourteen districts in India resulted from the storm was approximately $4.5 billion Ten people in Myanmar were reported to have been killed by the tropical cyclone, while another 20,000 families were left homeless. When Cyclone 05B reached its peak intensity of 912 mb, it became the most intense Tropical Cyclone of the North Indian Basin. (Reliefeffort, 1999)
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CHAPTER- 4 - OBSERVATIONS 4.1. RESEARCH ON CYCLONE RESISTANT ARCHITECTURE 4.2. CONCLUSION/ADVICES 4.3.PERSONAL INTERVIEWS/SURVEYS
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4.1. RESEARCH ON CYCLONE RESISTANT ARCHITECTURE Design of the House We do have control over the shape of new buildings and shape is the most important single factor in determining the performance of buildings in cyclones. Simple, compact, symmetrical shapes are best. The square plan is better than the rectangle since it allows high winds to go around them. The rectangle is better than the Lshaped plan. This is not to say that all buildings must be square. But it is to say that one must be aware of the implications of design decisions and take appropriate action to counter negative features. The best shape to resist high winds is a square.
Figure 12,Ankush Agarwal
IMAGES SOURCE: CYCLONE RESISTANT ARCHITECTURE BY ANKUSH AGRAWAL
If other shapes are desired, efforts should be made to strengthen the corners. If longer shapes are used, they must be designed to withstand the forces of the wind. Most houses are rectangular and the best layout is when the length is not more than three (3) times the width. In case of construction of group of buildings, a cluster arrangement can be followed in preference to row type. (Agrawal, 2007)
Roofs Lightweight flat roofs are easily blown off in high winds. In order to lessen the effect of the uplifting forces on the roof, the roof Pitch should not be less than 22ยบ. Hip roofs are best, they have been found to be more cyclone resistant than gable roofs.
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General Design Considerations 2. Avoid a low pitched roof, use a hip roof or a high pitched gable roof. 3. Avoid overhanging roofs. If overhangs or canopies are desired, they should be braced by ties held to the main structures. 4. Avoid openings which cannot be securely closed during a cyclone. Where openings are already in existence, cyclone shutters should be provided. Overhangs, patios and verandahs experience high wind pressures and should be kept short and Small • Avoid large overhangs as high wind force build up under them. • Overhangs should not be more than 18 inches at verges or eaves. • Build verandah and patio roofs as separate structures rather than extensions of the main building. • They may blow off without damaging the rest of the house. Securing the Ridge If the rafters are not secure, the ridge can fall apart when strong wind passes over the roof. The ridge can be secured by using:(i) COLLAR TIES - Timbers connecting the rafters. Nail them to the side of the rafters. (ii) GUSSETS - Usually made of steel/plywood. This is used at the ridge. (iii) METAL STRAPS over the top of the rafters. Securing the corrugated galvanized sheets The sheets are gauged by numbers. The Higher the number the thinner the material. Example 24 gauge galvanized sheet is superior to 28 gauge. (i) How does roof sheeting fail in cyclones? (ii) Failure in roofs If the sheeting is too thin or there are too few fittings, the nails or screws may tear through the sheet. (iii) If galvanized sheets are used, 24 gauge is recommended. (iv) How to secure sheeting to the roof structure, use • Fixings every two (2) corrugation at ridges, eaves and overhangs. • Fixings every three (3) corrugation. Maximum spacing at all other locations or use galvanised iron flats under the fixings. Page | 37
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(v) Fixings for sheetings Use fittings with a broad washer or dome head (zinc nail). To use more fixings for each sheet, put in the laths at closer centres and nail closer together. Screws • Use proper drive crews for corrugated galvanized roof sheets. • Be sure that the screws go into the purlins at least fifty (50) mm. • use large washers under the screw heads to prevent the roof sheets from tearing when pulled upward by high winds. Nails • Nails do not hold as well as screws. • Use nails with wide heads and long enough to bend over below the lath. • Galvanized coated nails are better than ordinary wire nails. Laths spacing and fixing • Spacing for laths and number of fixings will vary with the gauge of sheeting used. • Screws hold better than nails so fewer screws can be used. But the sheeting must be thick or they will tear through. • Laths should be placed closer together for thin sheets to provide space for extra fixings. • A guide to the number of fixings and spacing of laths is shown below.
Clay tile roofs:- Because of lower dead weight, these may be unable to resist the uplifting force and thus experience heavy damage, particularly during cyclones. Anchoring of roof tiles in R.C. strap beams is recommended for improved cyclone resistance. As alternative to the bands, a cement mortar screed, reinforced with galvanized chicken mesh, may be laid over the high suction areas of the tiled roof. Note:- Covering the entire tile roof with concrete or ferro-cement will prevent natural breathing through the tiles and will make them thermally uncomfortable.
Thatch roof: - Thatched roof should be properly tied down to wooden framing underneath by using organic or nylon ropes in diagonal pattern. The spacing of rope should be kept 450 mm or less so as to hold down the thatch length. For connecting the wooden members, use of non corrodible fixtures should be made. If non-metallic elements are used, these may need frequent replacement. After a Page | 38
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cyclone warning is received, all the lighter roofs should be held down by a rope net and properly anchored to ground. (i) Sheeted roofs:- A reduced spacing of bolts, ž of that admissible as per IS:800, recommended. For normal connections, J bolts may be used but for cyclone resistant connections U – bolts are recommended. Alternatively a strap may be used at least along edges to fix cladding with the purlins to avoid punching through the sheet. Properly connected M.S. flat can be used as reinforcing band in high suction zones. The corrugated sheeting should be properly overlapped (at least 2 1/2 corrugation) to prevent water from blowing under the seam. Spaces between the sheeting and the wall plate should be closed up to prevent the wind from getting under the sheeting and lifting it. This can be done by nailing a fascia board to the wall plate and rafters. (ii) Clay tile roofs:- Because of lower dead weight, these may be unable to resist the uplifting force and thus experience heavy damage, particularly during cyclones. Anchoring of roof tiles in R.C. strap beams is recommended for improved cyclone resistance. As alternative to the bands, a cement mortar screed, reinforced with galvanized chicken mesh, may be laid over the high suction areas of the tiled roof. Note:- Covering the entire tile roof with concrete or ferro-cement will prevent natural breathing through the tiles and will make them thermally uncomfortable. (iii)Thatch roof: - Thatched roof should be properly tied down to wooden framing underneath by using organic or nylon ropes in diagonal pattern. The spacing of rope should be kept 450 mm or less so as to hold down the thatch length. For connecting the wooden members, use of non corrodible fixtures should be made. If non-metallic elements are used, these may need frequent replacement. After a cyclone warning is received, all the lighter roofs should be held down by a rope net and properly anchored to ground. (iv)Anchoring of roof framing to wall/posts:- The connection of roof framing to the vertical load resisting elements i.e. wall or post, by providing properly designed anchor bolts and base plates is equally important for overall stability of the roof. The anchoring of roof framing to masonry wall should be accomplished through anchor belts embedded in concrete cores. The weight Connection of roof framing to wall traming (Agrawal, 2007)
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Anchoring of roof framing in masonry Bracing the raftered roofs of participating masonry at an angle of half horizontal to 1 vertical should be more that the total uplift at the support. In case of large forces, the anchoring bars can be taken down to the foundation level with a structural layout that could ensure the participation of filler and cross walls in resisting the uplift. (v) Bracing:- Adequate diagonal or knee bracing should be provided both at the rafter level and the eaves level in a pitched roof. The purlins should be properly anchored at the gable end. It is desirable that at least two bays, one at each end, be braced both in horizontal and vertical plane to provide adequate wind resistance. Where number of bays is more than 5, use additional bracing in every fourth bay.
Figure 13,CRBA,Ankush Agrawal
Wall Openings Openings in general are areas of weakness and stress concentration, but needed essentially for light and ventilation. The following are recommended in respect of openings. (i) Openings in load bearing walls should not be within a distance of h/6 from inner corner for the purpose of providing lateral support to cross walls, where „hâ€&#x; is the storey height upto eave level. (ii) Openings just below roof level be avoided except that two small vents without shutter should be provided in opposite walls to prevent suffocation in case room gets filled with water and people may try to climb up on lofts or pegs. (iii) Since the failure of any door or window on the wind-ward side may lead to adverse uplift pressures under roof, the openings should have strong holdfasts as well as
Figure 14,CRBA,Ankush Agrawal
closing/locking arrangement.
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4.2. CONCLUSION/ADVICES THE TEN KEY PRINCIPLES OF CYCLONE RESISTANT CONSTRUCTION
Choose the location carefully to avoid the full force of the wind or flood Figure 15,DW-Devolopment Workshop-cyclone
Use building layout with a simple regular shape, to avoid concentration of pressure. Figure 16,DW-Devolopment Workshop-cyclone
Build the roof at an angle of 30째 to 45째 to prevent it being lifted off by the wind.
Figure 17,DW-Devolopment Workshop-cyclone
Figure 18,DW-Devolopment Workshop-cyclone
Avoid wide roof overhangs; separate the veranda structure from the house.
Make sure the foundations, walls, and roof structure are all firmly fixed together.
Figure 19,DW-Devolopment Workshop-cyclone
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Reinforce the bracing in the structure; strengthen walls and joints/ junctions to increase stiffness. Figure 20,DW-Devolopment Workshop-cyclone
Make sure the roof covering is firmly attached to the roof structure to prevent it from lifting. Figure 21,DW-Devolopment Workshop-cyclone
If doors & shutters cannot be shut, make sure there are opposing openings to reduce pressure build up. Figure 22,DW-Devolopment Workshop-cyclone
Use doors and shutters that can be closed.
Figure 23,DW-Devolopment Workshop-cyclone
Plant trees around the house as wind breaks and reduce flow of water, but not too close.
Figure 24,DW-Devolopment Workshop-cyclone
(DW-cyclone, 1989-93)
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DESIGN PROCEDURE FOR WIND RESISTANTBUILDINGS: Determine the wind forces a. Determine the design wind velocity Vz and normal design pressure P^ Vz =Vbki k2 k3 2 2 Pz = 0.0006 Vz , Pz will be in kN/m for Vz in m/s b. Corresponding to the building dimensions (length, height, width), the shape in plan and elevation, the roof typei and its slopes as well as projections beyond the walls, determine the coefficients for loads on all walls, roofs and projections, taking into consideration the internal pressures based on size and location of openings. Hence calculate the wind loads on the various elements nornnal to their surface. c. Decide on the lines of resistance which will indicate the bracing requirements in the planes of roof slopes, at eave level in horizontal plane, and in the plane of walls. Then, determine the loads generated on the following connections: • Roof cladding to Purlins • Purlins to rafters/trusses • Rafters/trusses to wall elements • Between long and cross walls • Walls to footings. Design the elements and their connections a. Load effects shall be determined considering all critical combinations of dead load, live load and wind load. In the design of elements, stress reversal under wind suctions should be given due consideration. Members or flanges which are usually in tension under dead and live loads may be subjected to compression under dead load and wind, requiring consideration of buckling resistance in their design. b. Even thin reinforced concrete slabs, say 75mm thick, may be subjected to uplift under wind speeds of 55 m/s and larger, requiring holding down by anchors at the edges, and reinforcement on top face! As a guide, there should be extra dead load (like insulation, weathering course, etc) on such roofs to increase the effective weight to about 375 kg/m . d. Resistance to corrosion is a definite requirement in cyclone prone sea coastal areas. Painting of steel structures by corrosion-resistant paints must be adopted. In reinforced concrete construction, a mix of M20 grade with increased cover to the reinforcement has to be adopted. Low water cement ratio with densification by means of vibratos will minimise corrosion. e. All dynamically sensitive structures such as chimney stacks, specially shaped water tanks, transmission line towers, etc. should be designed following the dynamic design procedures given in various IS codes. f. The minimum dimensions of electrical poles and their foundations can be chosen to achieve their fundamental frequency above 1.25 Hz so as to avoid large amplitude vibrations, and consequent structural failure. It may be emphasised that good quality of design and construction is the single factor ensuring safety as well as durability in the cyclone hazard prone areas. Hence ail building materials and building techniques must follow the applicable Indian Standard Specifications.
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4.3. PERSONAL INTERVIEWS/SURVEYS PERSONAL INTERVIEW WITH AN EXPERT IN DISASTER MANAGEMENT
Q. What are the severe effects of cyclones in India?
A. In India maximum effects will be life loss and property loss. So maximum loss is due to flooding, strong winds and storm surges. Many houses in flood prone areas will be flooded during these cyclones if u take recent cases of aila and lila there is a sever loss in the costal Andhra region . These caused a great damage to the houses,crops as well as life. Many buildings got torn by the cyclones.
Q. So , from all the above damages are there any mitigative measures provided by the Government ?
A. Yes the Government has provided post mitigative measures Cyclone Risk Mitigation Infrastructure: 1. Construction of Cyclone Shelters 2 .Construction of missing road links and bridges. 3 .Construction/renovation of embankments
Q. So what exactly does this mitigation project includes ?
A.This project is carried out by NDMA, Implimenting Agency
The project includes microlevel risk assessment up to village level for the higher vulnerability States. The key activities in this study are
I. Assess the nature of hazards, severity and frequency of occurrence of different cyclone related disasters, the areas likely to be affected, and duration of impact.
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II. Prepare state/district/mandal/taluka/village level hazard zonation maps for cyclone and other hazards referred above and classify settlements according to the hazard perception. III. Assess the vulnerability of the coastal communities for the preparation of composite risk atlas and maps IV. Provide information tools for regular up dating by NDMA/SDMAs/DDMA‟s and training of stakeholders V. Develop appropriate district specific risk management policy framework for evolving developmental
mitigation action plans through collation,
discussions and synthesis of hazard data; VI. Provide manuals for data interpretation for decision makers to plan appropriate interventions during emergencies
Q. Are there any principles or guide lines to be cleared before inaugurating a building for use ? if so what kind of principles should it follow focusing on stability and strength.
A. There are certain principles and codes to be achieved for a building to get a certification that it can be used for habitable purposes . firstly the site is to be tested for soil certification wheather the respected building can be constructed or not . there are several guiding principles to be followed to attain the earthquake resisance.
Q. We all know that many lives and much property damage is due to cyclone than earthquake in our climate zone and why do the buildings don’t have any clearance codes for cyclone resistance are there any codes available for cyclone resistant constructions ?
A. Generally there are no particular codes followed by the construction companies in the requirement of cyclone resistant . you know that cyclone is a seasonal disaster so it‟s a matter of days and generally normal buildings which were made of concrete and cement can with stand the cyclone . T hat‟s why there are no such codes developed particularly for cyclone resistance. But so far considered Gujarat had prepared some kind of guide lines for cyclone resistant structures.
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Q. So, what about our government does it going to produce or take any consequences on these issues?
A. Yes Almost all state governments are trying to get awareness in people for building a cyclone resistant buildings . Small campaigns are being held by both Government and also some private institutions. Q. What do you think about implementing Some certain codes into the construction field to make the building Cyclone resistant? A. of course one should put forward the issue like this to implement the codes for buildings to make them Cyclone resistant as the damage and loss is much more in cyclone than in earthquakes. Even other countries which are hurricane affected has introduced these kind of laws as a building code.Even I think its better to introduce those rules according to indian context. (Kuppili, 2012)
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LIST OF FIGURES: Figure 1 , CRBA ,Ankush Agarwal ........................................................................... 17 Figure 2, CBRA , Ankush Agrawal
................................................................... 17
Figure 3,, CBRA , Ankush Agrawal .......................................................................... 17 Figure 4, CBRA , Ankush Agrawal
................................................................... 18
Figure 5, CBRA , Ankush Agrawal ........................................................................... 18 Figure 6,CBRA , Ankush Agrawal ............................................................................ 19 Figure 7 , Figure 8 , Figure 9,Eenadu, Telugu newspaper ...................................... 32 Figure 10Orissa cyclone relief effort ......................................................................... 33 Figure 11 , Orissa cyclone relief effort ...................................................................... 33 Figure 12,Ankush Agarwal ....................................................................................... 36 Figure 13,CRBA,Ankush Agrawal ............................................................................ 40 Figure 14,CRBA,Ankush Agrawal ............................................................................ 40 Figure 15,DW-Devolopment Workshop-cyclone ...................................................... 41 Figure 16,DW-Devolopment Workshop-cyclone ...................................................... 41 Figure 17,DW-Devolopment Workshop-cyclone ...................................................... 41 Figure 18,DW-Devolopment Workshop-cyclone ...................................................... 41 Figure 19,DW-Devolopment Workshop-cyclone ...................................................... 41 Figure 20,DW-Devolopment Workshop-cyclone ...................................................... 42 Figure 21,DW-Devolopment Workshop-cyclone ...................................................... 42 Figure 22,DW-Devolopment Workshop-cyclone ...................................................... 42 Figure 23,DW-Devolopment Workshop-cyclone ...................................................... 42 Figure 24,DW-Devolopment Workshop-cyclone ...................................................... 42
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REFERENCES AND BIBILIOGRAPHY Acadamy, F. h. (2010). National Hurricane Center. Retrieved october 2012, from National Weather Service: http://www.nhc.noaa.gov/aboutnames.shtml Agrawal, A. (2007). Cyclone Resistant Building Architecture. Authority, N. D. (2010). National Cyclone Risk Mitigation Project . Retrieved August 2012, from National Cyclone Risk Mitigation Project (NCRMP): http://ncrmp.gov.in/ncrmp/Cyclone_Impact.html Dr.N.M. Bhandri,Dr.Prem Krishna,Dr.Krishen Kumar. (2009). Wind Storms , Damage and Guidelines for Mitigative Measures. Roorkee: IITK-GSDMA. DW-cyclone. (1989-93). Promoting generic principles of safe construction. Retrieved october 2012, from DW- Devolopment Workshop: http://www.dwf.org/en/content/ten-key-principles-cyclone-resistantconstruction Faridi, R. (2008, March 6). Natural disasters. Retrieved august 2012, from Earth Sciences: http://r ashidfar idi.wor dpr ess.com/2008/03/06/natur al-disaster scyclones/ Gibbs, T. (2001, January). Hurricanes and their Effects on Buildings and Structures in the Caribbean. Retrieved september 2012, from Organisation of American States: http://www.oas.org/pgdm/document/bitc/papers/gibbs/gibbs_01.htm Govt., A. (2012). Commonwealth of Australia. Retrieved september 2012, from Bureau of Meteorology: http://www.bom.gov.au/cyclone/history/index.shtml ISSD. (2012, june). India Metorological Department. Retrieved september 2012, from Ministry of earth sciences: http://www.imd.gov.in/section/nhac/static/cyclonehistory-bb.htm KantardŞića, E. (1996). Al Jazeera Balkans. Retrieved august 2012, from Al Jazeera: http://www.aljazeer%20a.com/weather%20/2012/03/2012368928291888.html Kuppili, R. (2012, october). Cyclone Disaster Management. (M. i. center, Performer) Office, Andhra Pradesh, India. Reliefeffort. (1999, november). Orissa cyclone Reliefeffort. Retrieved november 2012, from Collaboration of Orissa cyclone relief effort: http://www.collaboration.org/centers/orissa/cyclone.html
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Guidelines for Cyclone Resistant Construction of Buildings in Gujarat, Gujarat State Disaster Management Authority, Government of Gujarat, December 2001. Make the Right Connections; A manual on safe construction techniques prepared as part of the OAS/USAID Caribbean Disaster Mitigation Project (CDMP). Hurricanes and their Effects on Buildings & Structures in the Caribbean, Tony Gibbs, Director, CEP - This paper was presented at the USAID/OAS PGDM building inspector training workshop, held in Antigua in January 2001. Natural Hazards: Causes and Effects, Lesson 5: Tropical Cyclones – University of Wisconsin Disaster management Centre.
SSI scale is based on three parameters - maximum sustained wind speed, minimum central
pressure and level of storm surge.
NOAA Technical Memorandum, the Deadliest Tropical Cyclones, 1995. Compiled from NOAA and other sources. Bulletin of the American Meteorological Society, 1970, 2005, 1998 “Wind Storms , Damage and Guidelines for Mitigative Measures”: Dr.NMBhandri , Dr.Prem Krishna , Dr.Krishen Kumar. Rashid Faridi ,2008. National Institute of Disaster Management (NIDM). Nodal units in line departments. Cyclone resistant architecture by Ankush Agrawal. R. Ramachandran (November 13, 1999). "Scientific failures". India's National Magazine. Frontline. Retrieved February 23, 2008. SAARC DISASTER MANAGEMENT CENTRE-2010. Gujarat State Disaster Management Authority - Government of Gujarat December-2001 “Wind Storms , Damage and Guidelines for Mitigative Measures”: Dr.NMBhandri , Dr.Prem Krishna , Dr.Krishen Kumar http://www.imd.gov.in/section/nhac/static/cyclone-history-bb.html http://r ashidfar idi.wor dpr ess.com/2008/03/06/natur al-disaster s-cyclones/ Natural Disasters: Cyclones http://ncr mp.gov.in/ncr mp/Cyclone_Impact.html National Cyclone Risk Mitigation Project http://oas.or g/pgdm/document/bitc/paper s/gibbs/gibbs_01.htm Page | 49
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http://www.aljazeer a.com/weather /2012/03/2012368928291888.html http://clickbankbussinesbankdatabisnis.blogspot.com/2012/03/deadlycyclone-lashes-southeaster n.html SCIENCE & TECHNOLOGY: Deadly cyclone lashes southeaster n Africa http://aquafind.com/ar ticles/Cyclone.php Effects Of Cyclones On Fisheries And Aquaculture http://www.fr eelists.or g/post/lifesavior s/The-Or issa-India-case-studybudgeting-Palaces The Orissa, India, case study http://www.ear thzine.or g/2011/03/22/post-disaster -management-pover tyand-food/ Post Disaster Management, Poverty and Food | Earthzine http://cpr eec.or g/pubbook-costal.htm CPREEC Environmental Education Centre, Library Str uctur al Retr ofitting for Hur r icane Resistance http://www.fixya.com/suppor t/r 7988488-safe_constr uction_tips Safe Constr uction Tips -Pr oduct Pr oblem Suppor t ... http://icsehelp-r esour ces.blogspot.com/2011/05/natur al-disaster s.html Icse Resource Provider :Natural Disasters http://disaster management.ap.gov.in/website/cyclone.htm Andhra Pradesh Disaster Management Department http://ncr mp.gov.in/ncr mp/AnnIIa.html National Cyclone Risk Mitigation Project http://www.amssdelhi.gov.in/tr opicle_cyclones.htm HAZARDS OF CYCLONES http://english.tur kcebilgi.com/Disaster s
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