論 文 - J-Stage

J. of Wind Engineering, JAWEVol.47, No.2(No.171), April 2022

論　文

日本風工学会論文集第47巻第 2号（通号第171号）2022年 4月

――――――――――――――――――――――――――――――――――――――――――――――――――― *1 Senior Engineer, EHS & S Research Center, NTT Facilities, Inc. [email protected] *2 Professor, Faculty of Engineering, Tokyo Polytechnic University *3 Professor, School of Civil Engineering, Chongqing University （原稿受理年月日：2021 年 8 月 8 日，採用決定年月日：2022 年 3 月 12 日）

Worldwide Status on Legal and Regulatory Frameworks with Provisions Related to Wind-resistant Design of Buildings

Akira HAYAKAWA*1 Masahiro MATSUI*2 Yukio TAMURA*3

SUMMARY

Laws and/or regulations of 137 of 195 countries are discussed from the perspective of 3 types of provisions: wind-

resistant design liability, wind load calculation methods, and reference wind speeds or pressures. Studies of legal and regulatory jurisdictions and requirements reveal that (1) 137 countries mention or imply wind-resistant design liability, and 120 and 114 countries define wind load calculation methods and reference wind speeds or pressures, respectively; (2) 110 and 27 countries mention or imply wind-resistant design liability at the national and subnational levels, respectively, (3) 17 countries mention or imply only wind-resistant design liability and (4) 15 countries accept multiple different wind load calculation methods. Analyses of economic damage from storms and economic developments of countries confirm that the establishment of laws and/or regulations (1) does not necessarily directly depend on economic damage and (2) requires at least the lower middle income level of economic development.

keywords: building law, building regulations, wind-resistant design, legal framework, regulatory framework, wind-resistant design liability, wind load calculation method, reference wind speed, reference wind pressure, storm damage, economic development, worldwide status

1. Introduction Urbanization is proceeding in developing countries due to a

power shift in the world economy, but construction technologies have not kept up with economic growth in these countries. It follows that meteorological disasters, which are hypothesized to be influenced by the effects of climate change1), and terrestrial disasters, which are said to have entered an active period2), have been repeated in urban areas in the recent past. Thus, early enactment and proper enforcement of building laws and

regulations are becoming increasingly important from the viewpoint of urban risk management against natural disasters.

Building laws and regulations are crucial legal and regulatory tools for setting minimum requirements for sites, facilities, structures and uses of buildings to protect the lives, health, and property of people who use buildings. They also provide authorities with a major opportunity to pursue resource conservation and waste reduction and to manage risks associated with economic growth in construction work, which requires a

－ 5（ 1 ）－

high rate of material consumption and causes greenhouse gas emissions. In addition, they are required for management of work environments to ensure safety, security, and health of workers, and give a signpost to maintain and improve the skills of professional engineers and workers involved in long-term construction work, which has a high degree of danger. As such, they play an important role in socioeconomics and have therefore been investigated and analyzed for many countries by international organizations, especially from legal, regulatory and institutional aspects.3)4)5)

From technical aspects, on the other hand, many comparative studies have been carried out using different codes and standards for structural safety against a specific natural hazard. In the field of wind-resistant design of buildings, for example, evaluation and comparison of 7 major codes and standards have been conducted through discussions of estimations of alongwind, acrosswind, and torsional responses.6) Additionally, the scatter that exists among wind effects estimated by various codes and standards have also been assessed through comparisons of alongwind loads and their effects on tall buildings recommended by 5 of the 7 major codes and standards.7) Similarities and differences among external and internal pressures, exposure issues and topography in 3 major codes and standards have been discussed and attempts have been made to resolve some of the apparent discrepancies.8) As an international initiative, meanwhile, some important issues relevant to dynamic wind-induced responses for use in wind loading codes and standards were discussed in the working group set up by the International Association for Wind Engineering (IAWE) and some recommendations were made for harmonization of international codification for wind loads.9) Furthermore, comparative studies of design wind loads calculated by 15 different codes and standards from the Asia-Pacific Region have been carried out for low-, medium- and high-rise buildings and reported as a practical outcome of the International Workshops on Regional Harmonization of Wind Loading and Wind Environmental Specifications in Asia-pacific Economies (APEC-WW).10)11) However, no comparative study of codes and standards has been conducted for all countries of the world, and no effort has been made to try to understand the worldwide picture.

Based on this background, in the previous study12)13)14)15), laws and regulations and their supplemental documents related to wind-resistant design of buildings were investigated for a total

of 195 countries whose sovereignties have been determined, 193 of which are member states of the United Nations (UN) and 2 of which are observer states at the UN General Assembly, and individually overviewed for 137 countries whose laws and/or regulations were identified. Furthermore, codes and standards utilized for wind-resistant design of buildings, with or without legal and regulatory binding power, were also individually overviewed for the 195 countries. In this paper, the laws and/or regulations of the 137 countries are discussed from the perspective of 3 types of provisions: wind-resistant design liability, wind load calculation methods, and reference wind speeds or pressures. First, the presence or absence of these provisions are summarized for each country to understand the worldwide status. Next, legal and regulatory jurisdictions and requirements are studied for each provision to understand the worldwide status, and then analyzed to understand their relationships with economic damage from storms and economic developments of countries. This series of worldwide studies will serve as a reference for countries with an incomplete legal and regulatory framework to move forward with a more complete establishment.

2. Target Legal and Regulatory Frameworks The legal and regulatory frameworks for the 137 countries,

which account for 70% of the total, are targeted in this paper. Table 1 shows these countries with check marks “ ✓ ”. Hyphens “-“ in this table mean that laws and/or regulations related to wind-resistant design of buildings were not identified in this study, but do not always mean that they do not exist. Also, Table 2 shows their breakdown for each subregion. The numerical value in parentheses: ( ) in this table shows the total number of countries lie within each region and subregion. The divisions of region and subregion follow in principle the United Nations geoscheme16).

3. Provisions on Wind-resistant Design of Buildings Provisions related to wind-resistant design of buildings

mentioned within the legal and regulatory frameworks of the 137 countries are mostly divided into 3 types of provisions: wind- resistant design liability, wind load calculation methods, and reference wind speeds or pressures. 3.1 3 types of provisions (1) Wind-resistant design liability Wind-resistant design liability is mentioned or implied

－ 6（ 2 ）－

through 4 types of clauses that require: - specific wind load calculation methods as well as specific

wind speeds, velocity pressures or wind pressures, - consideration of the most unfavorable conditions due to

earthquakes or winds, - structural safety against strong winds, climatic extremes,

hurricanes, and storm risks, and/or - compliance with specific multiple countries rather than

specific codes and standards. The first type of clause includes the provision that simply

cites an existing nationally- or internationally-recognized code or standard. The second type includes the provision that does not clearly define wind load calculation methods as well as reference wind speeds, velocity pressures or wind pressures. The third type includes the provision that implicitly requires buildings to withstand strong winds. The fourth type includes the provision that follows other countries that impose wind-resistant design liability. (2) Wind load calculation methods Wind load calculation methods targeted for this study include all the procedures for calculating design wind loads on building structures, components and claddings, and therefore exclude specialized procedures for bridge structures and power and telecommunications facilities. Any of the alongwind loads or roof wind loads must at least be able to be estimated although there are differences among technical approaches. (3) Reference wind speeds or pressures Reference wind speeds or pressures are particularly important country- or site-specific values that underlie the setting of design wind loads and defined by any of the following 3 criteria: - wind speed, - velocity pressure, and/or - wind pressure.

Most of the reference wind speeds or pressures are defined as the wind speed or velocity pressure averaged over any period referenced to any height over any terrain for any probability of exceedance in one year with the effects of site distinctive conditions such as topographic and orographic effects removed. At the same time, some of them are defined as the wind speed or velocity pressure with any of averaging time, reference height, ground roughness or return period undefined, and the effects of site distinctive conditions may not be removed either. However, both are commonly provided by a map with isopleth lines or

zonings and/or a list organized by administrative jurisdictions or for large cities. On the other hand, some of them are defined as the wind pressure simplified to the safe side by incorporating building-specific conditions such as wind force and pressure coefficients together with site distinctive conditions. Most of them are simplified as a step function of height or a constant value regardless of height without considering the concepts of averaging time, ground roughness and return period. 3.2 Worldwide status

These provisions are organized for each country in Table 1. Suffixes: “s” and “m” attached to the check mark sign mean that each provision is legislated at subnational levels and accepts multiple different systems, respectively. Countries with an asterisk “*” after their names have established a federal government system. Administrative rules that are orders within an administrative agency and apply to public building construction activities are not considered even if they stipulate any of these provisions. As shown in this table, when reference wind speeds or pressures are defined within the legal and regulatory framework, wind load calculation methods are also stipulated therein. Furthermore, when wind load calculation methods are stipulated within the legal and regulatory framework, wind-resistant design liability is also mentioned therein. There is no converse, unsurprisingly.

Table 2 shows the number of countries with each provision for each subregion. The numerical value in parentheses: [ ] shows the percentage of the 195 countries. As shown in this table, all the 137 countries covered in this paper mention or imply wind-resistant design liability. Of these, 120 and 114 countries, 62% and 58% of the total, establish provisions regarding wind load calculation methods and reference wind speeds or pressures, respectively.

Figure 1 shows the worldwide distribution of countries with the legal and regulatory framework. Here, countries colored green, orange and yellow are those that require all 3 types of provisions, 2 types of provisions: wind-resistant design liability and wind load calculation methods, and only 1 type of provision: wind-resistant design liability, respectively. The countries colored gray are those that do not fall under any of the above. Hyphens "-" are synonymous with those in Table 1. As shown in this figure, the countries colored green are the majority in the Americas, Asia, Europe, and Oceania. On the other hand, many of the countries colored gray are found in Africa, especially in Middle Africa and Western Africa.

－ 7（ 3 ）－

Table 1. List of countries whose legal and regulatory frameworks require each provision

Country Wind-resistant design liability

Wind load calculation methods

Reference wind speeds or pressures

Country Wind-resistant design liability

Wind load calculation methods

Reference wind speeds or pressures

Africa Sierra Leone - - - Eastern Africa Togo - - -

Burundi - - - Americas Comoros* - - - Caribbean Djibouti - - - Antigua and Barbuda ✓ ✓ ✓ Eritrea - - - Bahamas ✓ ✓ ✓ Ethiopia* ✓ ✓ ✓ Barbados - - - Kenya - - - Cuba ✓ - - Madagascar ✓ ✓ ✓ Dominica ✓ - - Malawi ✓s - - Dominican Republic - - - Mauritius - - - Grenada ✓ ✓m ✓m Mozambique ✓ ✓ ✓ Haiti - - - Rwanda ✓ ✓ ✓ Jamaica ✓ ✓ ✓ Seychelles ✓ ✓ ✓ St. Kitts and Nevis* ✓ ✓ ✓ Somalia* - - - St. Lucia - - - South Sudan* - - - St. Vincent and the

Grenadines ✓ ✓ ✓ Tanzania ✓ ✓ ✓ Uganda ✓ ✓ ✓ Trinidad and Tobago - - - Zambia - - - Central America Zimbabwe ✓s ✓s ✓s Belize ✓ - -

Middle Africa Costa Rica ✓ ✓ ✓ Angola ✓ - - El Salvador ✓ ✓ ✓ Cameroon - - - Guatemala ✓ ✓ ✓ Central African Republic - - - Honduras ✓ ✓ ✓ Chad - - - Mexico* ✓s ✓s ✓s Congo-Brazzaville - - - Nicaragua ✓ ✓ ✓ Congo-Kinshasa - - - Panama ✓ ✓ ✓ Equatorial Guinea - - - Northern America Gabon - - - Canada* ✓s ✓s ✓s Sao Tome and Príncipe - - - United States* ✓s ✓s ✓s

Northern Africa South America Algeria ✓ ✓ ✓ Argentina* ✓ ✓ ✓ Egypt ✓ ✓ ✓ Bolivia ✓s ✓s ✓s Libya - - - Brazil* ✓s ✓s ✓s Morocco ✓ - - Chile ✓ ✓ ✓ Sudan* - - - Colombia ✓ ✓ ✓ Tunisia - - - Ecuador ✓ ✓ ✓

Southern Africa Guyana - - - Botswana ✓ ✓m - Paraguay ✓s ✓s ✓s Eswatini ✓ ✓ - Peru ✓ ✓ ✓ Lesotho ✓ - - Suriname ✓ ✓ ✓ Namibia ✓ ✓ ✓ Uruguay - - - South Africa ✓ ✓ ✓ Venezuela* ✓ ✓ ✓

Western Africa Asia Benin - - - Central Asia Burkina Faso - - - Kazakhstan ✓ ✓ ✓ Cabo Verde ✓ ✓m - Kyrgyzstan ✓ ✓ ✓ Cote d’Ivoire ✓ - - Tajikistan ✓ ✓ ✓ Gambia - - - Turkmenistan ✓ ✓ ✓ Ghana ✓ ✓ ✓ Uzbekistan ✓ ✓ ✓ Guinea-Bissau - - - Eastern Asia Guinea-Conakry - - - China ✓s ✓s ✓s Liberia - - - Japan ✓ ✓ ✓ Mali - - - Mongolia ✓ ✓ ✓ Mauritania ✓ - - North Korea - - - Niger - - - s : Provisions that are defined at subnational levels. Nigeria* ✓s ✓s - m : Provisions that accept multiple different systems. Senegal ✓ - - * : Country that establishes the federal governing system.

－ 8（ 4 ）－

Table 1. List of countries whose legal and regulatory frameworks require each provision (continued)

Country Wind-resistant design liability

Wind load calculation methods

Reference wind speeds or pressures

Country Wind-resistant design liability

Wind load calculation methods

Reference wind speeds or pressures

South Korea ✓ ✓ ✓ Finland ✓s ✓s ✓s South-eastern Asia Iceland ✓ ✓ ✓

Brunei ✓ ✓m - Ireland ✓ ✓ ✓ Cambodia - - - Latvia ✓ ✓ ✓ Indonesia ✓ ✓ ✓ Lithuania ✓ ✓ ✓ Laos - - - Norway ✓ ✓ ✓ Malaysia* ✓s ✓s ✓s Sweden ✓ ✓ ✓ Myanmar - - - United Kingdom ✓s ✓s ✓s Philippines ✓ ✓ ✓ Southern Europe Singapore ✓ ✓m ✓m Albania ✓ ✓ ✓ Thailand ✓ ✓ ✓ Andorra - - - Timor-Leste - - - Bosnia and Herzegovina* ✓s ✓s,m ✓s Vietnam ✓ ✓ ✓ Croatia ✓ ✓ ✓

Southern Asia Greece ✓ ✓m ✓m Afghanistan - - - Holy See ✓ ✓ ✓ Bangladesh ✓ ✓ ✓ Italy ✓ ✓ ✓ Bhutan ✓ ✓ - Malta - - - India* ✓s ✓s ✓s Montenegro ✓ ✓m ✓m Iran ✓ ✓ ✓ North Macedonia ✓ ✓m ✓m Maldives ✓ - - Portugal ✓ ✓m ✓m Nepal* ✓ ✓ ✓ San Marino ✓ ✓ ✓ Pakistan* ✓s ✓s,m ✓s Serbia ✓ ✓ ✓ Sri Lanka - - - Slovenia ✓ ✓ ✓

Western Asia Spain ✓ ✓ ✓ Armenia ✓ ✓ ✓ Western Europe Azerbaijan ✓ ✓ ✓ Austria* ✓s - - Bahrain - - - Belgium* - - - Cyprus ✓ ✓ ✓ France ✓s ✓s ✓s Georgia ✓ ✓ ✓ Germany* ✓s ✓s ✓s Iraq* ✓ ✓ ✓ Liechtenstein ✓ - - Israel ✓ ✓ ✓ Luxembourg ✓ ✓ ✓ Jordan ✓ ✓ ✓ Monaco ✓ - - Kuwait - - - Netherlands ✓s ✓s,m ✓s Lebanon ✓ - - Switzerland* ✓s ✓s ✓s Oman - - - Oceania Palestine ✓s - - Australia and New Zealand Qatar ✓ ✓m ✓m Australia* ✓s ✓s ✓s Saudi Arabia ✓ ✓ ✓ New Zealand ✓s ✓s ✓s Syria ✓s ✓s ✓s Melanesia Turkey ✓ - - Fiji ✓ ✓ ✓ United Arab Emirates* ✓s ✓s,m ✓s Papua New Guinea ✓ ✓ ✓ Yemen - - - Solomon Islands - - -

Europe Vanuatu ✓ ✓ ✓ Eastern Europe Micronesia

Belarus ✓ ✓ ✓ Federated States of Micronesia* - - - Bulgaria ✓ ✓m ✓m

Czech ✓ ✓ ✓ Kiribati ✓ ✓ ✓ Hungary ✓ ✓ ✓ Marshall Islands - - - Moldova ✓ ✓ ✓ Nauru - - - Poland ✓ ✓ ✓ Palau - - - Romania ✓ ✓ ✓ Polynesia Russia* ✓ ✓ ✓ Samoa ✓ ✓ ✓ Slovakia ✓ ✓ ✓ Tonga ✓ ✓ ✓ Ukraine ✓ ✓ ✓ Tuvalu - - -

Northern Europe s : Provisions that are defined at subnational levels. Denmark ✓s ✓s ✓s m : Provisions that accept multiple different systems. Estonia - - - * : Country that establishes the federal governing system.

－ 9（ 5 ）－

Table 2. Number of countries whose legal and regulatory frameworks require each provision

Region Subregion Wind-resistant design liability

Wind load calculation methods

Reference wind speeds or pressures

Africa (54)

Eastern Africa (18) 9 8 8 Middle Africa (9) 1 0 0

Northern Africa (6) 3 2 2 Southern Africa (5) 5 4 2 Western Africa (16) 6 3 1

Subtotal 24 17 13

Americas (35)

Caribbean (13) 8 6 6 Central America (8) 8 7 7

Northern America (2) 2 2 2 South America (12) 10 10 10

Subtotal 28 25 25

Asia (48)

Central Asia (5) 5 5 5 Eastern Asia (5) 4 4 4

South-eastern Asia (11) 7 7 6 Southern Asia (9) 7 6 5 Western Asia (18) 14 11 11

Subtotal 37 33 31

Europe (44)

Eastern Europe (10) 10 10 10 Northern Europe (10) 9 9 9 Southern Europe (15) 13 13 13 Western Europe (9) 8 5 5

Subtotal 40 37 37

Oceania (14)

Australia and New Zealand (2) 2 2 2 Melanesia (4) 3 3 3 Micronesia (5) 1 1 1 Polynesia (3) 2 2 2

Subtotal 8 8 8 Total (195) 137 [70] 120 [62] 114 [58]

The numerical values of in parentheses: ( ) and [ ] show the total number of countries that lie within each region and subregion and the percentage of the 195 countries, respectively.

4. Legal and Regulatory Jurisdiction

In many countries, the law that requires structural safety of buildings and at the same time confers the power for making regulations to the central government and local governments is enacted by the legislature, which is the sole legislative organ of the country. In this case, to achieve structural safety of buildings, wind-resistant design liability is mentioned in the law, and wind load calculation methods and reference wind speeds or pressures are provided in the regulations made by responsible administrative agencies under the central government and local governments. Most of them are provided through either or both of 2 types of regulations that require: - their own code or standard developed based on existing

codes and/or standards, and/or - existing codes and/or standards without any change.

The first type of regulations means that the responsible administrative agency makes regulations that define wind load

calculation methods with nationally- or internationally-recognized codes and/or standards simplified and/or combined, together with reference wind speeds or pressures. In addition, the regulations in which existing wind load calculation methods and reference wind speeds or pressures were revised are also included in this type. Even if existing codes and/or standards are partially accepted without any change in the regulations, the scopes of applications are clearly distinguished from the developed parts. On the other hand, the second type means that the responsible administrative agency makes regulations only to list nationally- or internationally-recognized codes and/or standards that define wind load calculation methods and/or reference wind speeds or pressures. If internationally-recognized codes and/or standards are listed as wind load calculation methods in the regulations, reference wind speeds or pressures are generally defined considering climatic conditions of their own country at the same time. Unlike the first type, the

－ 10（ 6 ）－

second type, which is often seen in emerging countries, is not always properly adjusted to the educational and technical levels of their own country as well as aligned with the regulations against other natural disasters such as earthquakes.

Table 3 shows the number of countries with each provision by national and subnational legislation. Here, the national and subnational legislations are defined as legislations enacted by central and local governments, respectively. National legislations were also considered when both national and subnational legislations were identified in the same country. As shown in this table, countries that establish these provisions at the national level are a majority of the countries with their respective legislations. Their numbers are 110, 96 and 91, which account for 56%, 49% and 47% of the total, respectively. Meanwhile, the numbers of countries that include them within subnational jurisdictions are 27, 24 and 23, which account for 14%, 12% and 12% of the total, respectively. They make up approximately 20% of the countries with their respective legislations.

On the other hand, it is natural that the legal and regulatory framework is influenced by the government system of each country. The government system is categorized into any of the

unitary or federal government systems. A unitary government system is one in which a country is governed as a single entity by a central government, and a federal governing system is one in which a country is governed as a political entity characterized by a union of partially self-governing states or provinces under a central federal government. 168 and 27 of the 195 countries have unitary and federal government systems, respectively.

In many cases, national and subnational legislation correspond to legislation under unitary and federal government systems, respectively. However, there are some exceptions. National legislation is not established in 13 countries within the unitary government system, which add 7 countries with overseas territories: China, Denmark, Finland, the United Kingdom, France, the Netherlands and New Zealand to 6 countries: Malawi, Zimbabwe, Bolivia, Paraguay, Palestine and Syria. This often originates to a great extent from historical and geographical backgrounds. On the other hand, a national legislation with higher enforcement is established in 7 countries within federal government systems: Ethiopia, St. Kitts and Nevis, Argentine, Venezuela, Nepal, Iraq and Russia.

Figure 1. Worldwide distribution of countries whose legal and regulatory frameworks require each provision

Color Wind-resistant design liability

Wind load calculation methods

Reference wind speeds or pressures

✓ ✓ ✓ ✓ ✓ - ✓ - - - - -

－ 11（ 7 ）－

Table 3. Number of countries with national and subnational legislation

Region Wind-resistant design liability Wind load calculation methods Reference wind speeds or pressures National

legislation Subnational legislation

National legislation

Subnational legislation

National legislation

Subnational legislation

Africa 21 3 15 2 12 1 Americas 22 6 19 6 19 6

Asia 30 7 27 6 25 6 Europe 31 9 29 8 29 8 Oceania 6 2 6 2 6 2

Total 110 [56] 27 [14] 96 [49] 24 [12] 91 [47] 23 [12] The numerical value in parentheses: [ ] shows the percentage of the 195 countries.

5. Legal and Regulatory Requirements

Provisions related to wind-resistant design of buildings are also characterized by dividing the 3 types of provisions into 2 groups: wind-resistant design liability, and wind load calculation methods and reference wind speeds or pressures as below. 5.1 Wind-resistant design liability

Some countries do not explicitly define any wind load calculation methods, or reference wind speeds or pressures within the legal and regulatory framework, although wind-resistant design liability is mentioned or implied through a part of the provisions mentioned therein. 17 countries that place the check mark sign in only the field of wind-resistant design liability of Table 1 fall into this category. These countries correspond to those that mention wind-resistant design liability through the aforementioned second to fourth clauses that require: - the most unfavorable conditions due to earthquakes or

winds to be taken into consideration, - structural safety to be ensured against strong winds,

climatic extremes, hurricanes, and storm risks, and/or - specific multiple countries to be followed rather than

specific codes and standards. The first and second groups of countries do not define a

specific wind load calculation method and reference wind speed or pressure. 3 countries: Morocco, Cuba and Turkey, and 12 countries: Malawi, Angola, Lesotho, Cote d’Ivoire, Mauritania, Senegal, Dominica, Belize, Maldives, Palestine, Austria and Monaco, are classified into the first and second groups, respectively.12)13) On the other hand, the third group does not even imply the importance of wind-resistant design. 2 countries: Lebanon and Liechtenstein, belong to this group.12)13)

Table 4 shows the number of countries mentioning or implying only wind-resistant design liability for each region. 14 and 3 countries require wind-resistant design liability at the national and subnational levels, respectively. The 3 countries

are Malawi, Palestine and Austria.

Table 4. Number of countries mentioning or implying only wind-resistant design liability

Region National legislation

Subnational legislation Total

Africa 6 1 7 Americas 3 0 3

Asia 3 1 4 Europe 2 1 3 Oceania 0 0 0

Total 14 [7.2] 3 [1.5] 17 [8.7] The numerical value in parentheses: [ ] shows the percentage of the 195 countries. 5.2 Wind load calculation methods and reference wind speeds or pressures

Some countries accept multiple different systems of wind load calculation methods and reference wind speeds or pressures within the legal and regulatory framework. Most of them accept either of the 2 systems that adopt: - any of two or more internationally-recognized wind load

calculation methods and reference wind speeds or pressures, or

- any of their own rather old or other country-developed internationally-recognized wind load calculation methods and reference wind speeds or pressures. The former is because their own wind load calculation

methods and reference wind speeds or pressures have not been developed. The latter is because their own wind load calculation methods and reference wind speeds or pressures have not been updated. At any rate, these countries are in the transition phase from old to new wind load calculation methods and reference wind speeds or pressures in accordance with national and subnational policies and plans or multilateral agreements.

Table 5 shows the number of countries adopting multiple

－ 12（ 8 ）－

different systems for each region. This table, however, excludes countries that adopt: - one system of wind load calculation methods and reference

wind speeds or pressures within each jurisdiction, and - two or more almost the same systems of wind load

calculation methods and reference wind speeds or pressures within each jurisdiction.

The former includes 7 countries: Mexico, China, Malaysia, Denmark, the United Kingdom (UK), France and New Zealand, which have multiple different systems at the national level but adopt only one system at the state or provincial level including overseas territories.12)13) The latter includes 7 countries: Canada, the United States (US), India and Australia, which accept both previous editions and the current edition with new findings in addition to previous editions; Ghana, which accepts both the UK national standard and the national standard based on the same UK national standard; Bolivia, which accepts both the municipal and national standards developed based on the same series of the US academic society standards; and Switzerland, which publishes the national annex for the European Union standard

serving as an index of relevant parts of the current professional society standards.12)13)14)

15 and 8 countries with the check mark sign with suffix “m” in the fields of wind load calculation methods and reference wind speeds or pressures of Table 1, respectively, fall into this category. Multiple wind load calculation methods are accepted at the national level in 11 countries: Botswana, Cabo Verde, Grenada, Brunei, Singapore, Qatar, Bulgaria, Greece, Montenegro, North Macedonia and Portugal. Of these, no reference wind speed or pressure is defined in 3 countries: Botswana, Cabo Verde and Brunei. However, multiple wind load calculation methods are accepted at the subnational levels in 4 countries: Pakistan, the United Arab Emirates, Bosnia and Herzegovina and the Netherlands. Of these, only one common reference wind speed or pressure is defined for multiple systems in 2 countries: the United Arab Emirates (Dubai) and the Netherlands (Bonaire, St. Eustatius and Saba), and reference wind speeds or pressures are defined for only one specific system in 2 countries: Pakistan and Bosnia and Herzegovina.

Table 5. Number of countries defining multiple wind load calculation methods and reference wind speeds or pressures

Region Wind load calculation methods Reference wind speeds or pressures

National legislation

Subnational legislation Total National

legislation Subnational legislation Total

Africa 2 0 2 0 0 0 Americas 1 0 1 1 0 1

Asia 3 2 5 2 0 2 Europe 5 2 7 5 0 5 Oceania 0 0 0 0 0 0

Total 11 [5.6] 4 [2.1] 15 [7.7] 8 [4.1] 0 [0.0] 8 [4.1] The numerical value in parentheses: [ ] shows the percentage of the 195 countries

6. Discussions

Economic damage from storms and economic developments of countries are assumed to be significant factors in establishing laws and/or regulations related to wind-resistant design of buildings. In this chapter, the relationships with legal and regulatory jurisdictions and requirements are discussed from these 2 standpoints. 6.1 Economic damage from storms (1) Overall trend

Figure 2 shows the number of countries with and without any laws or regulations for each country classification according to the levels of maximum economic damage per storm disaster. Countries are classified into 4 levels: no/low loss (less than

US$1K), medium loss (between US$1K and US$60,000K), high loss (between US60,001K and US$480,000K) or extreme loss (more than US$480,000K). Of these, the last 3 levels are divided into almost the same number of countries for easy comparison. All damage and economic losses directly or indirectly related to storm disasters over the last 50 years from 1971 to 2020 are considered based on the international disasters database17): EM-DAT. Storms here include 3 types of storms: convective storms, extra-tropical storms and tropical cyclones. Parts colored dark and light green show countries with and without any laws or regulations, respectively.

As shown in this figure, 74 (=33+41) countries are classified into no/low loss, which have not experienced any

－ 13（ 9 ）－

significant economic damage from storms. Of these, 41 countries, which account for 21% of the total, have enforced laws and/or regulations. On the other hand, 41, 40 and 40 countries have experienced significant economic damage from storms, and are classified into medium, high and extreme losses, respectively. Of these, 25 (=11+9+5) countries, 13% of the total, have not enforced any laws or regulations, although their number slightly decreases with the rise of economic damage level. These facts mean that economic damage from storms does not necessarily directly lead to the establishment of laws and/or regulations related to wind-resistant design of buildings. (2) Trends in jurisdictions and requirements Figure 3 shows the number of countries with laws and/or regulations for each country classification according to the levels of maximum economic damage per storm disaster. The upper diagram shows the number of countries that enforce laws and/or regulations at the national or subnational levels (dark and light green). The middle diagram shows the number of countries that define all 3 types of provisions, 2 types of provisions: wind-resistant design liability and wind load calculation methods, and only 1 type of provision: wind-resistant design liability (3 greens from dark to light). The lower diagram shows the number of countries that accept multiple different systems of wind load calculation methods and reference wind speeds or pressures.

None of these diagrams show a significant relationship between the number of countries and economic damage levels. As shown in the middle diagram, however, it is notable that 7 (=3+4) countries of high or extreme loss define only wind-resistant design liability. These countries: Morocco, Cuba, Dominica, Belize, Lebanon, Turkey and Austria, have developed and adopted national codes and/or standards, or accepted specific internationally-recognized codes and/or standards in practice.14) Nevertheless, in order for these countries to reduce economic damage from storms as much as possible, wind load calculation methods and reference wind speeds or pressures should also be defined through laws and/or regulations, and an administrative system should be established to properly enforce them. 6.2 Economic developments of countries (1) Overall trend

Figure 4 shows the number of countries with and without any laws or regulations for each country classification according to the levels of gross national income (GNI) per capita. Countries are classified into 4 levels: low income (US$1,045 or less), lower middle income (between US$1,046 and US$4,095),

upper middle income (between US$4,096 and US$12,695) or high income (US$12,696 or more). This classification is based on the World Bank Country and Lending Groups18) for 194 countries excluding the Holy See. Parts colored dark and light blue show the same as the contents shown in Figure 2.

As shown in this figure, 129 (=38+45+46) countries that have enforced laws and/or regulations, are classified into lower middle, upper middle or high income. Just 7 countries are classified as low income. The percentages are 67% and 3.5% of the total. Also, their number drastically increases from low to lower middle incomes, and then slightly increases from lower middle to high incomes. Countries classified as low income, most of which are also classified as least developed countries19), are confronting severe structural impediments to sustainable development, and therefore have difficulty in having a comprehensive ability to undertake legal, institutional, technical and financial means to achieve safe building constructions. Therefore, at least the lower middle income level of economic development is considered to be required for the establishment of laws and/or regulations. (2) Trends in jurisdictions and requirements

Figure 5 shows the number of countries with laws and/or regulations for each country classification according to the levels of GNI per capita. Contents shown in these diagrams are the same as those shown in Figure 3.

As shown in the upper diagram, the difference in the number of countries classified as low or lower middle incomes, which have established laws and/or regulations at the national level, is more remarkable than is that shown in the overall trend. Also, this number is significantly decreased from upper middle to high incomes, unlike the overall trend. These are because the number of countries with laws and/or regulations at subnational levels roughly tends to increase with the rise of economic developmental level. As shown in the lower diagram, furthermore, the number of countries that accept multiple different systems also increases with the rise of economic developmental level. These facts mean that higher income countries are more capable of enforcing laws and/or regulations at the subnational level and properly using multiple different systems than are lower income countries. As shown in the middle diagram, on the other hand, there are more lower middle income countries that define only 1 type of provision than there is any other income country. The same is true for countries that define 2 types of provisions. Countries on this level can

－ 14（10）－

recognize and proclaim the importance of wind-resistant design for sustainable developments of buildings as higher income countries do. Therefore, a little more financial and technical

support by higher income countries and international organizations will help these countries achieve a full establishment of laws and/or regulations.

Figure 2. Number of countries with and without any laws or

regulations by economic damage levels from storms

Figure 4. Number of countries with and without any laws or regulations by economic developmental levels of countries

Figure 3. Number of countries with laws and/or regulations by economic damage levels from storms

Figure 5. Number of countries with laws and/or regulations by economic developmental levels of countries

7

38 45 4620

17 9 12

0

20

40

60

80

Lowincome

Lowermiddleincome

Uppermiddleincome

Highincome

Num

ber o

f cou

ntrie

s

Countries without any laws or regulationsCountries with laws and/or regulations

3513

49

13

6

2

6

13

0

20

40

60

Num

ber o

f cou

ntrie

s

Laws and/or regulations at subnational levelsLaws and/or regulations at the national level

9 1 3 43 3 0 0

2926 28 31

0

20

40

60

Num

ber o

f cou

ntrie

s

1 type of provision 2 types of provisions3 types of provisions

8 1 4 20

20

40

60

No/lowloss

Mediumloss

Highloss

Extremeloss

Num

ber o

f cou

ntrie

s Multiple different systems

5

32 39 332

66 13

0

20

40

60

Lowincome

Lowermiddleincome

Uppermiddleincome

Highincome

Num

ber o

f cou

ntrie

s

Laws and/or regulations at subnational levelsLaws and/or regulations at the national level

1 8 5 304 1 16

26 39 42

0

20

40

60

Num

ber o

f cou

ntrie

s

1 type of provision 2 types of provisions3 types of provisions

0 2 6 70

20

40

60

Lowincome

Lowermiddleincome

Uppermiddleincome

Highincome

Num

ber o

f cou

ntrie

s Multiple different systems

4130 31 35

33

11 9 5

0

20

40

60

80

No/lowloss

Mediumloss

Highloss

Extremeloss

Num

ber o

f cou

ntrie

s

Countries without any laws or regulationsCountries with laws and/or regulations

－ 15（11）－

7. Conclusions This paper has discussed laws and regulations of 137 of 195

countries, which account for 70% of the total, from the perspective of 3 types of provisions: wind-resistant design liability, wind load calculation methods, and reference wind speeds or pressures. First, the presence or absence of these provisions were summarized for each country to understand the worldwide status. Next, legal and regulatory jurisdictions and requirements were studied for each provision to understand the worldwide status, and then analyzed to understand their relationships with economic damage from storms over the last 50 years from 1971 to 2020 and economic developments of countries assuming that they were significant factors in establishing legal and regulatory frameworks. The results are summarized as follows: - 137 countries at least mention or imply wind-resistant

design liability within legal and regulatory frameworks. Of these, 120 and 114 countries, which account for 62% and 58% of the total, also define wind load calculation methods and reference wind speeds or pressures therein, respectively;

- 41 countries at the level of no/low loss, which means that they have not experienced any significant economic damage from storms, have enforced laws and/or regulations. However, 25 countries at the levels of medium, high or extreme loss, which mean that they have experienced significant economic damage from storms, have not enforced any laws or regulations. The percentages are 21% and 13% of the total. Thus, economic damage from storms does not necessarily directly lead to the establishment of laws and/or regulations;

- 129 countries, 67% of the total, are at the levels of lower middle, upper middle or high income. Only 7 countries, just 3.5% of the total, are at the level of low income. The level of at least lower middle income is considered to be required for the establishment of laws and/or regulations;

- 110 countries, 56% of the total, have established laws and/or regulations at the national level. Of these, only 5 are at the level of low income. Their number drastically increases from low to higher incomes;

- 27 countries, 14% of the total, have established laws and/or regulations at subnational levels. Their number tends to increase with the rise of economic development level;

- 17 countries, 8.7% of the total, define only wind-resistant design liability. Of these, the largest 8 countries are at the level of lower middle income. More financial and technical support for these countries is considered to be necessary for the full establishment of laws and/or regulations;

- 15 countries, 7.7% of the total, legally accept multiple different wind load calculation methods. None of them are at the level of low income, and their number increases with the rise of economic development level.

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