Conservation and revitalization of Huizhou small towns based on the theory of urban catalyst. The West Street historic district of Keenmun town in Huizhou as an example

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CONSERVATION AND REVITALIZATION OF

HUIZHOU SMALL TOWNS BASED ON THE THEORY OF

URBAN CATALYST - THE WEST STREET HISTORIC

DISTRICT OF KEENMUN TOWN IN HUIZHOU AS AN

EXAMPLE

STUDENT NUMBER 891983

SURNAME WANG

NAME DANXIANG

SCHOOL ARCHITECTURE URBAN PLANNING CONSTRUCTION ENGINEERING

COURSE SUSTAINABLE ARCHITECTURE AND LANDSCAPE DESIGN

- ARCHITETTURA SOSTENIBILE E PROGETTO DEL PAESAGGIO - PC

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ABSTRACT

With the rapid development of urbanization and modernization, huizhou small town historical areas have the universality and particularity of China's small towns. Therefore, they are worthy of being treated separately in the face of the protection and revitalization of historical areas. Reasonable protection of built heritage in small towns is the premise of revitalization, and only revitalization and development can better protect built heritage. Nowadays, a large number of cultural tourism projects are springing up in cities and villages, which undeniably protect some urban architectural heritage and play a great role in the revitalization of some villages. But these dreams are too special to be an example of small-town development. The protection and revitalization of the architectural heritage of small towns need to find a suitable development path.

This article explores the urban catalyst concept to guide the small towns protection and revitalization of the strategy, study the basic principle and function of the catalyst, mechanism and characteristics of core and analysis of urban catalyst strategy to solve the feasibility of the historic towns face a dilemma of huizhou, through summarizing plug-in technique involved in conservation, to use alternative protection.

Key word: Urban Catalyst,Small Town，Historic District, Huizhou, Conservation And

Revitalization, Plug-In Method.

CHAPTER 1 INTRODUCTION

1.1The research background

With the gradualy deepening of the process of new-type urbanization in China, a large number of historical built environments can not adapt to modern development and gradually decline. The contradictions between social and economic development and built environmental protection are becoming increasingly apparent. As a carrier of a large number of architectural heritage, small towns are sandwiched between cities and villages. Without proper protection and revitalization strategies, the contradictions are more prominent. China is now at the top of the consumer society. Everything is dominated by the economy, everything is symbolized, and cultural characteristics are symbolized. The Chinese government

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has established a cultural tourism company to promote the market with a combination of culture and tourism. It is undeniable that cooperation between culture and tourism can revitalize the local economy, but it also brings some side effects. It does bring some economic revitalization, but the dislocation of urban construction values will cause irreversible damage to heritage protection. In the long run, revitalization is also one-sided and short-lived.

The conservation of historical and cultural heritage originally focused on the conservation of monumental and individual buildings with architectural significance. Over time, however, it has been noted throughout the world that demolition is often carried out without knowing what is actually being demolished under the pretext of urban expansion or modernization; Unreasonable and inappropriate reconstruction has caused serious damage to the historic district.1

Urban historic district: the research on the conservation and revitalization of building heritage is mostly concentrated in urban and rural areas, while there is a lack of effective and targeted research on the conservation and revitalization of historic district in small towns. The discussion on the reconstruction mode of historical districts has been going on for a long time.

Ruan yi san2 _{divides the conservation model of historical districts in China into the}

following categories according to its different ways of conservation and renewal, which are respectively as follows: Shanghai "XINTIANDI" model; Tongxiang "wuzhen" model; Beijing "south pool" model; But most of these model are concentrated in or around cities. The current concept of conservation and revitalization has also entered some scenic villages, such as Wencun3 _renovation

project and Bishan4 _project

Due to sufficient capital support and strong commercial properties, these existing historic districts in the city are generally renovated on a large scale and can be properly protected and utilized.conservation and revitalization of ruralbuilding heritage, the villages have unique natural scenery and relatively simple folk customs. With the trend of rural tourism and design going to the countryside, the villages are transformed into villages for urban people, and a number of buildings and functions are transformed to meet urban needs, such as WenCun reconstruction. Or whole villages become tourist attractions, over-commercialized, like HongCun5_{.There are also a small range of artists and designers into the}

countryside, although only a small scale of transformation, but more to create a utopia for people in the city.

Building heritage conservation of small towns is different from the cities and the countryside, especially for some small towns in the economically backward areas, on the one hand, its relative lack of funds, on the other hand social properties and structure characteristics of small towns, very different from developed regions, the natural environment also didn't reach the level of country, refer to these areas of

1（NACIYE DORATLI，Revitalizing Historic Urban Quarters: A Model for Determining the Most Relevant Strategic Approach，European Planning Studies Vol. 13, No. 5, July 2005）

2 Ruan yisan, born in November 1934, is the director of the national research center of historical and cultural cities in tongji university, ministry of construction of China

3 The village community designed by Wang Shu. With the basic tone of grey, yellow and white, the facade design of rammed earth wall, mud wall, grey stone wall and cut rockery presents his ideal beautiful livable village.

4 On June 5, 2011, the "Bishan plan", an art project to the countryside, was officially launched in Guangzhou times art museum as the launch of "Bishan community". A series of activities will be held to explore the new possibilities of rural reconstruction in Huizhou and to seek a new rural construction mode integrating multiple functions.

5 A village in Yi town, Huangshan City in the historical Huizhou region of southern Anhui Province, China,Together with Xidi, the village became a UNESCO World Heritage Site in 2000

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transformation patterns meaningless or even counterproductive. As a result, a number of stereotyped historical districts have become mere imitations, and residents' lives have not been improved in practice.6

Managing and effectively using changes in historic sites for present and future needs is better than a rigid respect for the sacred past."

1.2Research objectives:

The conservation and revitalization of built heritage has become a widely accepted view in the world. However, the problems faced by built heritage in different urban scales are different. The successful strategies of one place cannot be copied to another place. The research scope of thisthesis is the historical districts in the built heritage of Huizhou small towns. Through the analysis of relevant cases at home and abroad, to find a suitable concept and method for the conservation and revitalization of historic districts in small towns.

Based on conservation and revitalization of the introduction of insertion technique and concept of urban catalyst as the starting point, analysis summary and summarized the connotation of insertion technique and the theory of urban catalyst and the action principle, from the perspective of urban catalyst, exploring the theory of urban catalyst in a small town in the historical district design method, the principles, strategies and practice to guide the small town built heritage conservation and revitalization, activate the historical district, in the concrete research catalyst points at the same time, summarizes insertion technique, handle the relationship between the new and old buildings, as the research target of this article.

On the basis of the above practical methods, the historical districts of small towns in Huizhou area are selected as the research object, because they have the universality of small towns and the uniqueness of regional culture. Then, the present situation of Qimen west street in Huizhou is selected to analyze, explore its potential resources, and put forward the revitalization strategy of urban catalyst theory. Try to adjust the urban functional structure of the function decline, and by increasing the public space, the road system adjustment, select plug-in technique combined with catalytic points to shape the effective node, the contemporary gimmick to conservation ofbuilding heritage conservation, and then through catalytic node shape and design to achieve energy recovery, economic recovery, the recovery of history, has a practical value.

1.3Research significance:

Identify the value of historic city districts as capital stock - in addition to their intangible aesthetic value; Building and environmental quality; Value as part of cultural heritage; Promoting continuity of urban/community memory - plays a key role in changing attitudes towards the conservation/conservation of these areas.7

Nowadays the revitalization of historic urban quarters brings many benefits to the

6 （Ma Qingfeng ，The renewal and transformation of the Historic District in the small towns of the Post rural epoch— —Take Huangtun old street as an example，Hefei University of Technology Hefei, Anhui, P.R.China April, 2017 ） 7 （NACIYE DORATLI，Revitalizing Historic Urban Quarters: A Model for Determining the Most Relevant Strategic Approach，European Planning Studies Vol. 13, No. 5, July 2005）

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cities and the local residents both socially and economically.It also provides enhancement of human development. During the renewal of historic urban quarters is not creating new urban fabric or fabricating a fake history in these places. In the historic urban quarters renewal in China, when it comes to reconstruction, the conflict arises in how to deal with the relationship between the historical culture value and the traditional characteristics of the modern daily life.

How to strike a balance between revitalization and conservation, and how to deal with the relationship between the old buildings and the new buildings in the historic district.If china only has big cities and medium-sized cities without small towns, the political center, economic center and cultural center in the countryside will have no legs. As the political, economic and cultural center of the countryside, small towns are a concept that needs to be recognized.8

The transformation of historic districts in small towns should be different from that in “rural revitalization” and that in urban villages. Small cities and towns of historical district is city memory and the old city center, for this type of Renaissance, should consider update more infrastructure, restore the community environment, cultural atmosphere, homesickness and historical texture, not just in order to attract tourists, more is to provide local residents with a living place of education and cultural entertainment. On the basis of these, some cultural innovation points are provided. These are the features and significance of a small town historic district.

1.4The research methods

This thesis use literature review and case study methodology in order to retrieve the needed information. The choice of the proposed methods satisfies the overall goal on the research. Thus, the thesis aims to provide an understand of the urban catalyst and revitalizing historic urban quarters, as well as observing how the two work together.

Five major electronic bibliographic databases were used for data search: Google Scholar, National Knowledge Infrastructure (CNKI), Wanfang Data, Chinese Education Library.

8 （张江华著深入与反思：费孝通的小城镇理论与 30 年来的中国城镇化实践出版社：社会科学文献出版社；第_{1 版；2015 年 12 月}

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CHAPTER 2 Explanation of relevant theoretical

concepts

2.1 Definition of building heritage

Built heritage consists of all aspects of the man-made historic environment such as houses, factories, commercial buildings, places of worship, cemeteries, monuments and built infrastructure such as roads, railways and bridges; physically created places such as gardens, mining sites and stock routes; and other places of historical significance such as archaeological sites.9

Gustavo Giovannoni, a renowned conservation scholar in Italy, Developed a series of urban conservation methods,The concept of "urban heritage" was proposed.An important principle of its establishment is the conservation of historical monuments "Built environment" can show the accumulation of timeThe urban fabric is also strongly opposed to treating historic districts like museums General seal up the practice. He is also a historian of the city Management and conservation developed a whole methodology that is still being developed today As the basis of urban conservation methods.10

to call attention to the proper treatment of "minor architecture" in architectural conservation and urban renewal, thus opening a new era of urban conservation. "Secondary architecture", usually non-monumental general architecture, includes all forms of architectural art as well as all types of architecture.

1999 ICOMOS the 12th conference by the Charter of the Built Vernacular Heritage modes on the Built Vernacular Heritage), directly using the concept of Built Heritage. As local (local)building heritage has the characteristics of overall construction, it is better to call it local (local) built heritage to pay attention to the environmental characteristics and landscape value of heritage.

Today, the concept of urban heritage is expanding. According to Michel Rautenberg, an international heritage expert, there are two types of cultural heritage that can be distinguished:

The first category is heritage by designation, which means all the projects are registered, designated and protected after being evaluated by experts.

The second category is heritage by appropriation, which means social or national cultural heritages, including landscapes, town styles, living places and buildings without outstanding historical landmarks.

According to this obviously expanded definition of urban heritage, urban built heritage should include the following three categories:

(1) commemorative heritage with outstanding cultural value;

9 http://modernheritage.com.au/mhm/understand_heritage/what-is-built-heritage/

10 Francesco bandlin, wu rifan. Heritage management in the urban age -- historic urban landscape and its methods [M]. Pei jieting, trans. Shanghai: tongji university press, 2017, p14-15.

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(2) there are no outstanding heritage elements, but relatively rich characteristics of coherence and consistency;

(3) new urban elements to be considered. It includes "urban built form", "open space between buildings", "greenway", "blue road" and other new types of urban heritage.11

Built heritage "is not only the remains of activities of ancestors, but also the living space of today's people". It is most directly affected by urbanization, with the greatest cultural conflicts and contradictions, and has great practical research significance. In terms of time span, the concept of urban built heritage is open. With the change of time and the gradual evolution of social and cultural thoughts, modern architecture is increasingly integrated into the vision of heritage conservation. However, modern life and historical environment gradually present a complex attitude of opposition.

The significance of heritage places can change over time as community values evolve. Conservation does not require them to be preserved in their original condition or use, only that any alteration or development for contemporary use and enjoyment retains it original heritage features. In addition to regular maintenance, conservation may include conservation, restoration, reconstruction, adaptation and interpretation.

2.2 Definition the small town

Fei xiaoto12 _{believes that "small towns are social entities at a higher level than}

rural communities. Such social entities are communities composed of a group of people who are not engaged in agricultural production and labor, regardless of geographical, demographic, economic and environmental factors Look, they both have different characteristics from the countryside, but also maintain an indispensable contact with the surrounding countryside." 13

2.21people of small town:

The population is more balanced. In terms of age, the number of young people is limited. A large number of young people go to cities above the county seat, but small towns have middle-aged people and people of a certain age returning home.

In terms of family structure, the average household population is 3 people, 80 percent are small and micro families with less than 4 people, and 60 percent are nuclear families composed of 2 generations. The family structure is relatively stable.

In terms of education level and household registration structure, the overall quality of the population is not high, with the education level at junior middle school or below as high as 74%, college or above only 10%, 21% of the residents are still engaged in agricultural production in rural areas.

In terms of employment structure, 65% of households in small towns have wage income, 62% have family operating income, 2% have property income and 25% have transfer income. Income level is not high, an average of about 3,000 yuan, after retirement farming is even lower.

In terms of the source of residents, 72% of the permanent residents in built-up

11 Zhang song， From the conservation of famous historical and cultural cities to the conservation of completed heritage (school of architecture and urban planning, tongji university 05, 2019, 8p)

12 Fei xiaotong， Chinese sociologist who published the book "rural China"

13 zhang jianghua, depth and reflection: fei xiaotong's theory of small towns and the practice of urbanization in China in the past 30 years （Press: social sciences academic press; Version 1. December 2015)

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areas of small towns live in families, and 28% of the families move into built-up areas in the later stage, and most of them move in in the last 20 years.

2.22Small town life:

In terms of consumption, percapita consumption expenditure, residents in small towns are only 46% of the average level of urban residents and 28% of the average level of first-tier urban residents, higher than rural residents

The distribution of public services, daily travel "20 minutes of life cycle." The township mainly provides basic education, medical care, residents' services and other public services, but the service quality is poor

2.23. Economy of small towns

Mainly workers and peasants. Most small towns develop with the advantage of local resources. In terms of economic characteristics, the total amount and per capita level of small towns are relatively low, so they can survive economically. 2.24 Small town space:

Most of them are near mountains and rivers. In terms of layout characteristics, river and road are in the majority, common strip development, dependent on the road, narrow road and small district, the public center of small towns is usually the main street or market.

From the road network pattern, small towns road network "informal", irregular. The area of small town is dominated by low-rise buildings and most of the scale is small。 in terms of community level, most of them are open communities.

In general, the overall pattern of small towns is free to grow, road network is informal and relatively free, land use is mixed, most of the function is to solve the living problems of residents. Due to its low density and natural state, it has a certain charm compared with cities, but its facilities and services are relatively backward

In china, small towns generally refer to the towns approved by the state, which are called organizational towns, including counties and other organizational towns. These counties or towns are the main body of small towns. They are relatively large in scale and have a good non-agricultural industrial base. They have certain ability to absorb surplus rural labor force.

Small towns are the main carrier of absorbing surplus rural labor force, the main body of the current population, the link between rural and urban areas, and the main force in the process of urbanization in China.14

In thisthesis, the environment of urban and rural residents in China is simplified into cities, small towns (compared with piacenza, Italy) and villages.Therefore, the build heritage mentioned in thisthesis refers to the material environment that has been carrying People's Daily life and has a certain complete scale and historical accumulation since its completion, such as historic towns, historic districts, ancient towns, historical cultural features and historic urban landscape.

2.3 Definition and development of historic district in small

town

Many cities have historic neighborhoods that give them a sense of place and identity through the history and culture they offer. They are often a reflection of a city's charm, vitality, and an integral part of the city. Their vision and function are an

14 何俊乔 The Point of Survival of Towns Historical districts—Mastery of Authenticity （天津大学建筑学院，july， 2009）

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important part of a city's Figure and identity. Since historic districts are usually located in the center of town, they are also part of the revitalization of the city15

The historic urban quarter gained attention in 1930s. The “Athens Charter” -a first internationally recognized programmatic document in urban planning area -mentioned the issue of “architecture and area with historical value”.16 _{Specifically,}

the Charter states that “ancient buildings with historical value should be properly protected”, with the main contents being the following:

1. Retained the buildings which are representative and can raise interest and educate people.

2. Preserve the architecture without impeding to the health of residents.

3. All main roads should avoid going through the ancient building area, thus avoiding the crowding traffic which could hinder the urban organic development 17

The 1964 Venice charter contains 16 articles in six parts: definition, conservation, restoration, historic site, excavation and publication. The concept of historical relic building is clarified

Article I: the essence of a historic site includes not only individual buildings, but also urban or rural environments from which a unique civilization, significant development or historical event can be identified. This applies not only to great works of art, but also to some of the more ordinary works of art of the past, which have cultural significance when the light disappears. Article 6: conservation of historical sites shall include environmental conservation of a certain scale. Where traditional environments exist, they must be protected. No new construction, demolition, reconstruction, change the relationship between the main body and color.18

In the Washington charter of 1987, the definition of a historic district is that it is located in a town with a certain historical significance, including not only the old urban area in the city center, but also other urban areas that retain historical features and traditional values.They possess mixed uses, traditional characteristics and specific functions, a historical identity with a unique local character, a historic fabric and street pattern. They are the centers of the social, economic and cultural life of the towns.19

Nowdays, there are many definitions and explanations of historical district in Chinese academic circles. historical district should have the following characteristics:

(1) it has a certain scale and relatively complete landscape features.

(2) to a certain extent, real historical information is preserved, including not only physical buildings or structures,

At the same time also should include immaterial traditional culture or traditional way of life.

(3) it plays a very important role in the local life, and is constantly developing and renewing

Vigor.20

“Historic urban district should be considered as part of an economic dynamism; they are rarely autonomously functioning zones and they usually have a symbiotic

15 Tiesdell, S., Taner, O. & Tim, H. 1996. Revitalizing Historic Urban Quarters. London: Architectural Press. P7 16 (Source: Australia ICOMOS. The Burra Charter: The Australia ICOMOS Charter for Places of Cultural Significance. Burwood: Australia International Council of Monuments and Sites. 1999.)

17 _{From Wikipedia, the free encyclopedia，https://en.wikipedia.org/wiki/Athens Charter}

18 From Wikipedia, the free encyclopedia，https://en.wikipedia.org/wiki/Venice_Charter

19 (Tiesdell, S., Oc, T. & Heath, T. (1996) Revitalizing Historic Urban Quarters, pp. 18–39, 41–42, 135 (Cornwall:Architectural Press).)

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relationship with the rest of the city. They must,therefore, be considered within the context of the city as a whole, and their conservation has to be considered, not as a straightforward and restrictive concern with conservation, but as a concern with revitalization and enhancement”.21

2.4 Definition conservation and revitalization of historic

district of small towns

What is revitalization?

In its simplest form revitalization is defined as: “The process through which the mismatch between the services offered by the fabric of the historic quarters and the contemporary needs can be reconciled”.22

The examination of successful examples of revitalization projects of historic urban quarters implies that the correct diagnosis of two contextual attributes during the analytical stage plays a key role in their success:

The level of obsolescence of physical, functional and locational characteristics; The dynamics of the place.

The direction of revitalization can be roughly divided into:

1.Physical revitalization: adaptation of the physical fabric to contemporary requirements through various modes of renewal.

2.Economic revitalization: revitalization and purposeful occupation of the improved/enhanced building stock (through physical revitalization) to sustain revitalization in a long-term perspective, and to enable the area to compete with the rest of the city.

This thesis mainly discusses how to revitalize the historic districts of small towns from the physical aspect.

What is conservation?

conservation is the act or process of protecting something that already exists to sustain life. In keeping with something that has life, which in this case means anything from a single building to a district, it may be necessary to inject new life. Conservation does not rule out change, without the ability to change a city will perish.23

The conservation of historic towns and urban areas is understood to mean those steps necessary for conservation, conservation and restoration of historic areas as well as their development and harmonious adaptation to contemporary life.24

This can only be achieved through good management, and the adoption of appropriate strategies.

To conserve existing (sometimes historic) buildings or districts by putting them to good contemporary use. This approach gives historic buildings and districts a ‘second life’ by reconnecting them with society.

Many cities have quarters that confer on them a sense of place and identity through the historic and cultural associations they provide. They are often an integral part of

21 Graham, B. (2002) Heritage as knowledge: Capital or culture?, Urban Studies, 39(5 –6), p. 1006. 22 Tiesdell, S., Oc, T. & Heath, T. (1996) Revitalizing Historic Urban Quarters, (Cornwall:Architectural Press). 23 Cantacuzino, S. (1990) A policy for architectural conservation, in: A. H. Imamuddin, et al. (Eds) Architectural and Urban Conservation in the Islamic World,thesiss in Progress, Vol. 1, p. 14 (Geneva: The Aga KhanTrust for Culture). 24 (ICOMOS, 1987).

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the city’s charm and appeal, and their visual and functional qualities are important elements of the city’s Figure and identity. In addition, as historic quarters are often located in central areas, their revitalization is often part and parcel of the general revitalization of cities .25

Conservation and revitalization are both future-oriented actions. conservation and revitalization are both focused on creating a Future of the Past. So conservation and revitalization efforts have to be addressed to make the concerned areas ‘ready for the future’ and to make the areas competitive with the rest of the cities of which they are part.

2.5 Problems And Challenges Of The Contemporary

Historic District In Small Towns

1 wave of urbanization

At this speed of development, historic districts in small towns often face the threat of real estate development. With the operation of commerce and the injection of a large amount of capital, and the echo of the government, many excellent residential buildings and representative buildings were regarded as the symbol of dilapidated houses and backward buildings because they were not designated as cultural relics conservation units. They were completely demolished and rebuilt, and traditional residential buildings and streets disappeared in the reconstruction of the old city.

2High population density and lack of the refurbishment to the building

scientifically

The buildings full of history in historic district are out of time for construction and revitalization, material aging and full of outdated facilities.Following the increasing population density, the overloaded to repair, unauthorized construction or alteration, a lot of historic buildings were changed dramatically. Moreover, due to the lack of refurbishment and conservation, there are a lot of unsafe and abandoned buildings.However, thesebuilding heritage, irreversible, once the conservation of adverse, only with imitation to maintain memory

3.Unilateral and unitary conservation

The conservation of historic districts is equivalent to the conservation of individual important cultural relics in the districts, while ignoring that these buildings themselves are members of each environmental element in the districts. Only when they exist and rely on each other and integrate into one another can the historic districts be best protected. As mentioned above, in addition to the historic buildings, there are also some minor buildings, some of which are part of the street style. However, these buildings are not properly protected, so the whole street style is destroyed.

But now many of the historical district conservation will focus on individual have influence on the main building of environment control of these buildings is lax, cause deformation of districts in the streets, landscape visual corridor jams, surrounding buildings abrupt messy, and the district of overall harmony, focused, clear pattern of the original true embodied in such a narrow one-sided losing in the conservation of oneness.

4.Small towns

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The historical districts of small towns are restricted, and it is decided that the roads of big cities cannot be taken. Small towns do not have the resources of cities, so they should not be demolished or built. They need to control the development scope, establish the red line of conservation at different levels, and retain the breath of life. The destruction of tourists, the generation of garbage, the emission of harmful gases and other human factors affect the historic district. Through direct or indirect contact with local residents, local people will be influenced by tourists, who may change their personal values and behaviors, lifestyles, and moral values. Therefore, it is totally wrong to regard the historic city as a tourist resource.

5.The authenticity of the historic district remains

The conservation of historic districts is equivalent to general urban renewal and landscape design. However, this forced residents to move. In addition, traditional houses and markets have become tourist facilities. The old building was demolished and the new one was built in the name of conservation and development. A large number of antique streets have tourism functions.

However, this approach ignores cultural and historical values and focuses only on their economic value. This has resulted in valuable historic districts becoming "fake antiques". If the historic district loses the traditional way of life and social attributes, it also loses the authenticity of life and the original historical charm

6.Passive static conservation

For due to the negative static protect of historical district conservation unit blind pursuit of the status quo, think this is the best reflection of the true of a historic district, and not let the residents repair and improve their dilapidated house, makes the evolution of these buildings a dangerous house, gradually damaged, at the same time brings to the residents living in a life inconvenient, deep contradictions. The living condition of the aborigins in the historic districts in small towns is the key element of the authenticity of the districts and the main body that reflects the features of small towns. As a carrier, the historic districts themselves are different from the concept of the authenticity of individual historic buildings. Moreover, individual buildings should also distinguish the functions of people. Under such passive and static conservation, the initiative and interest of aboriginal life are separated from the district, which is bound to result in population migration, the desire for real estate development, and the gradually lonely historical district becomes an empty shell.

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CHAPTER 3 Theoretical Study Of Urban Catalyst

Theory

3.1 Theoretical background

In the late 1980 s, American architect Wayne Attoe,published in the American catalyst of urban architecture, the theory once appear, immediately is widely recognized in western academics, mentioned in the book: "a suitable for America's metropolitan style must be derived from the characteristics and inherent cases in American cities, rather than by the derived from foreign experience.26_{They think that}

the American way of urban renewal are too extensive and radical, In the process of transformation, western European architectural forms were introduced constantly and local buildings were largely demolished, which had a great impact on the native American culture. The book also analyzes the typical urban design cases in the western United States, from the Angle of urban design, puts forward the theory of urban catalyst, he mainly by applying the theory of urban catalyst as a kind of "appropriate" program, introducing new elements can be strategically recovery existing elements, in the heart of the city and do not need to change their nature, when catalyst has such a new life, it also affects the original urban environment.

In the background of the statement, they brought up the idea of urban catalyst and elaborated it in detail through the typical American urban design projects in the mid-west America. They postulated that the strategic introduction of new elements might revitalize existing ingredients of the urban center without necessarily changing them radically. And even as the catalyst stimulates such new life, it also affects the form, character, and quality of urban elements that are subsequently introduced.

3.2 Noun explanation

Waht is Catalyst？

The term “catalyst” is derived from the chemistry concept. The Oxford English Dictionary’s definition of a catalyst in the field of chemistry is: “substance that when present in small amounts increases the rate of a chemical reaction or process but which is chemically unchanged by the reaction; a catalytic agent (A substance which similarly slows down a reaction is occas. called a negative catalyst)”. The

26 《American Urban Architecture: Catalysts in the Design of Cities 》 University of California Press; Reprint.12.1992 .Wayne attoe

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meaning of "catalyst" may also be extended to: “one that precipitates a process or event, especially without being involved in or changed by the consequences”.

What is Urban catalyst？

Urban catalysts are new redevelopment strategies comprised of a series of projects that drive and guide urban development. Redevelopment efforts in the past, such as urban renewal and large-scale redevelopment projects, have often jeopardized the vitality of downtowns. The difference between the urban catalyst and these redevelopment strategies is that catalytic redevelopment is a holistic approach, not a cleanslate approach, to revitalizing the urban fabric. Many cities have considered urban catalysts as a means for revitalization. Among the most noted catalytic projects are sports stadiums and arenas: however not all catalytic projects have to be designed at such a grand scale, nor do all cities possess a threshold of support to successfully sustain such developments. 27

Urban catalysts are projects, landscapes or buildings, which drive and guide urban development and increase the number of users in an area. A catalyst should be conceived as a series of projects that revive the urban fabric.

According to Wayne Otto theory of urban catalysts, if we look at the development of the city from the perspective of “chemists” and regard it as a chemical reaction, the elements of each city can be used as reactants for chemical reactions.

Drawing on the extended definition of catalyst, it may be similarly be applied to urban catalyst, as an element which can promote the changing of city structure and change the speed and mode of city development. From urban perspective, the catalyst in the urban design may be described in the following way: “It is the positive impact an individual urban building or project can have on subsequent projects and, ultimately, the form of a city. It encourages designers, planners, andpolicymakers to consider the chain-reactive potential of individual developments on civic growth and urban regeneration”28

Catalytic theory does not prescribe a single mechanism of implementation, a final form, or a preferred visual character for all urban areas. Rather, it prescribes an essential feature for urban developments: the power to kindle other action. The focus is the interaction of new and existing elements and their impact on future urban form, not the approximation of a preordained physical ideal.29

As long as you welcome the introduction of new and vibrant elements, it is enough to improve and activate the surrounding other elements and elements. The interaction of elements and elements with space generates a larger catalytic point, which continues to influence the development of the surrounding area, forming a "chain reaction" and gradually forming a larger urban catalyst, driving and promoting the organic renewal of the whole region

3.3 Catalyst Reaction Characteristics

Integrity：The reaction process of urban catalyst is a process that constantly needs 27 _{Cermetrius Lynell Bohannon，2004，The Urban Catalyst Concept，Department of Landscape Architecture}

College of Architecture and Urban Studies

28 _{Attoe, W., & Logan, D., 1989. American Urban Architecture: Catalysts in the Design of Cities. 1st ed. Berkeley:}

University of California Press.

29 _{Attoe, W., & Logan, D., 1989. American Urban Architecture: Catalysts in the Design of Cities. 1st ed. Berkeley:}

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to influence the surrounding environment. Therefore, the process of reaction is not an isolated state. New elements introduced need to be connected with surrounding elements, so as to constantly generate more new links

Gentility：Urban catalyst strategy is a reaction process from the part to the whole,

which gradually influences the surrounding area through the improvement of local vitality, thus driving the renewal of the whole area. It's similar to urban acupuncture, which is not a crude way of removing everything, but in a gentlemanly way, respecting the history, respecting the site, respecting the people who use it, starting with the local area, elevating the local vitality and then affecting the surrounding area.Existing urban elements of value are enhanced or transformed in positive ways. The new need does not obliterate or devalue the old but can redeem it. A positive catalytic reaction should consider and understand its context.

Sustainability：The role of urban catalyst is to complete the renewal through the

driving of adjacent elements, which is transferred from one level to another. It's a process from small to large. The process of transmission is a process of gradual renewal, which can adapt to the complex environmental content of historical and cultural districts in a sustainable way without causing damage.

3.4 Urban Catalyst In Small Town Historic District

Conservation And Revitalization Principles

3.4.1Neo-regionalism

It refers to the architectural absorption of local, national or folk style, so that modern architecture reflects the specific style of the place. As a kind of contemporary creative tendency or school, it actually comes from the traditional localism, which is a kind of dialect or folk style in architecture. However, new regionalism is not the imitation or restoration of local traditional architecture. New regionalism is still an integral part of modern architecture. It follows modern standards and requirements in function and structure, but merely absorbs traditional things in form.30

Historical and cultural districts will exist certain regional differences, the conservation and renewal process should not be the same, to ensure that the modified historical district has its own characteristics.when applying the urban catalyst theory to the conservation and renewal of historical and cultural districts, the principle of regionalism should be followed to ensure that the spatial characteristics of historical and cultural districts do not change and avoid the deliberate pursuit of urban aesthetics and unified visual effects. Highlight the characteristics of small cities and towns, and the small towns of homesickness, small towns play a unique charm.

3.4.2The sense of the place

For urban catalysts to be successful they need to have a strong sense of place. “Place” is a commonly used word in the English language. The word comes with many connotations— physical, psychological, or social. The word’s various meanings convey a richness that expresses the role that “place” plays in our daily lives. We often associate place with home, but place takes on a deeper meaning than that. Places have the power to become symbols of ideals, Figure ability, and

30 _{Deng qingtan, deng qingyao. Contemporary architectural trends and schools: huazhong university of science and}

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hope.Fritz Steele31 _{identifies two aspects of “place”. The first is sense, which is the}

experience in a particular setting. The second is spirit, which is the combination of attributes that give a place personality. Sense of place is an interaction between people and settings that creates reactions such as feelings, perceptions, and behaviors.

The sense of place-the genius loci (Norberg schultz)-is a historic urban quarter’s most important aesthetic attribute which is to be maintained. The continuity and development of the quarter’s genius loci is therefore one of the most important design considerations in a historic urban quarter32

Historical and cultural districts take traditional culture as their soul, so they should adhere to the principle of cultural inheritance in their conservation and renewal. Pay attention to the building of the place spirit of the historical and cultural district and the continuation of the historical context. In the process of application of urban catalyst theory, local cultural connotation should be fully explored and original catalyst carriers containing historical connotations should be cut as little as possible to ensure the inheritance and continuation of traditional culture and avoid cultural fault

3.4.3 The diversity and applicability of functional formats

Historical and cultural districts of energy comes from the diversity of the function forms, as Jane jacobs in book 《birth and death of the great American cities》33_,

points out that "the city as a product of human settlement, tens of thousands of people gathered in the city, and the people's interests, ability, needs, wealth, and even taste are different, their correlation between constantly adapt to each other again at the same time, the result is a complex urban functions and support each other, and form a dynamic colorful urban space".34

Therefore, the application of urban catalyst theory should focus on the principle of diversity of functional formats to provide lasting vitality for historical and cultural districts.

3.4.4 Authenticity

Authenticity in design is a topic in design-related discussion today. Authenticity is a concern in catalytic developments, because new developments need to fit into their context. There is a large amount of literature available about the topic. The definition of the terms “authentic” and “inauthentic” often vary from critic to critic. Critics argue that some urban developments that draw from historical references lack authenticity.

Overall, the issue of design authenticity is critical to the discussion of urban catalyst and I have developed my own criteria for authenticity in urban design. I will use the concepts of “rooted” and “nonrooted” to identifying the type of authenticity a design or design elements have.

“Rooted” design means the project is ingrained or has some connection with the area in which it is located. This can be accomplished by either using local vernacular or a combination of building and landscape types. “Non-rooted” means the design or elements of the design are not particularly rooted in the area, but may be placed there due to economic or social reasons. Even though they are not

31 _{Steele, Fritz. 1981. The Sense of Place. Boston: CBI Publishing Company, Inc.}

32 _{Tiesdell, S., Oc, T. & Heath, T. (1996) Revitalizing Historic Urban Quarters, (Cornwall:Architectural Press).P.167}

33 _《_{The Death and Life of Great American Cities》1, 1992Jane Jacobs (Author)}

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originally rooted in place, “non-rooted” elements have the power to become ingrained. Overtime the users of the space, who impact meaning and sense of place through their presence, supply this characteristic. A good example of this is large chain restaurants,like the Hard Rock Cafe, that are placed in districts that already possess a strong character.These establishments survive because of the dollars that people, either locals or tourists, spend there. This makes the place a strong economic draw to the area even though it may not add to the inherit qualities of its context. We as designers see how badly these establishments unravel the fabric of a place, and need to be able to plan for more “rooted” developments to be created instead.

3.4.5Principle of elastic control

As a guiding strategy, urban catalyst theory has certain predictability in the conservation and renewal of historical and cultural districts. Once the catalytic effect in the early stage cannot be realized as expected at the beginning, it should be adjusted timely to ensure that the whole reaction process can be developed in a positive direction35

3.5 Selection Of Catalyst Direction

Obsolescence In any historic urban quarters, the buildings are constructed, or the man made environment is created in accordance with the needs and requirements, and within the overall framework of the prevailing socio-economic, cultural and political conditions in a country in general, and/or city in particular, at any point in time.Changes in these conditions, as well as the variance in developing needs and expectations through time, would result in a mismatch or conflict between the capability of building/group of building or the area. This mismatch, which is named as ‘obsolescence’,as aforementioned, leads such an area deep into the process of deterioration and decay.36

In daily life, what is faced in historic areas are symptoms of this process, which are simply addressed as problems of the area. It is possible to identify buildings in poor conditions; non-contemporary sanitary conditions; insufficient parking spaces; uses (activities) move to more accessible districts of the cities; narrow roads; buildings used for other, less suitable purposes; changes in the pattern of ownership; changing social composition; decreasing attractiveness; high number of incompatible uses; increasing vacancy rate as the symptoms of deterioration and decay, which an historic urban quarter faces.In fact, these ‘problems of the area’ are reflections of obsolescence.

3.5.1 Physical/structural obsolescence

Any building is subject to physical/structural deterioration, which leads to obsolescence.This may occur as a result of a variety of factors: the effects of time, the weather, earth movement, traffic vibration, and poor maintenance, etc. Obsolescence of this nature is likely to be, at least initially, of a relatively gradual process.37

35 _{Wenjing Ma，Research of the Historical cultural District conservation and Renewal Application Based on the Urban}

Catalystic Theory，School of architecture, zhengzhou university，2017

36 _{Cermetrius Lynell Bohannon，2004，The Urban Catalyst Concept，Department of Landscape Architecture}

College of Architecture and Urban Studies

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3.5.2 Functional obsolescence

The vitality of the city comes from the response of functional structure, the rational organization of functions can ensure the efficient operation of the city. How to reasonably organize and select the original functions to meet the needs of modern life is the key point in the conservation and renewal of historical and cultural districts

Obsolescence of this nature may arise due to the functional characteristics of the building/area. A building may fail to meet the contemporary standards and requirement of the user/potential user, on account of its design and fabric. The inadequacies of a building may range from the lack of contemporary sanitary fittings and spaces to central heating, air conditioning and other contemporary facilities. Functional obsolescence can arise in respect of all types of buildings including dwellings, factory buildings, etc. In addition to this,functional obsolescence may arise due to the characteristics and attributes of an area. The general characteristics, in other words, the morphology of the area—organic tissue with narrow streets—may create unfavourable conditions for traffic generating activities, and consequently result in decreasing the competitiveness of the area with respect to these activities.

3.5.3 Cluture Catalyst

Lewis mumford's view of culture is that "storing culture, spreading culture and creating culture are the three basic missions of a city".38_{As the carrier of culture,}

historic districts in small towns must play an important role in shaping the culture of the whole city.What the historic districts of small towns preserve is nostalgia, memory, community life and culture。

3.5.3.1Explicit cultural elements

Mainly include architectural culture and district texture, etc., and its existence form is relatively intuitive To present it directly in people's vision, the remodeling strategies are as follows:

1.Reconstruction Of Architectural Culture

Renzo Piano said that "the true universality of architecture should be achieved by seeking its roots, appreciating historical benefits and respecting local culture ".39 _It

can be seen that architectural culture, as a high cultural value, should be paid more attention to in its reconstruction and activation. Since each building can express the historical culture of an era, the form, color and material of its architecture are all with the rings of historical culture. The reconstruction of architectural culture is mainly to continue the style of the original architectural culture and make the old and new culture coordinate and coexist.

2.The Fabric Reconstruction Of The District

The texture of historical and cultural districts is generally characterized by "courtyard - alley - street"The reconstruction of district texture should focus on the continuation of the original texture, and the damaged texture should be carried out Proper repair and reinforcement

3.5.3.2The premise of recessive cultural elements

Retain the authenticity of life in historical and cultural districts and adopt the way It is mainly the conservation and inheritance of the original life style in the historical and cultural districts and the continuation and development of ethnic activities. 1.Retention and inheritance of life customs

The life customs in the historical and cultural district are more representative of

38 万莹.基于城市触媒理论历史街区更新策略探析[D]. [硕士学位论文]. 湖南大学建筑学, 2014. 39 Suyang，高技派的地域倾向，河南省科学研究院，2009

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food and clothing, they can Reflecting the ethnic characteristics of a district, it has a certain value of conservation. In view of these valuable cultural resources, It should be preserved and inherited to avoid disappearing in the renovation of historical and cultural districts.

2.Reproduction of the original way of life

The life style of residents can best reflect the authenticity of life in a historical and cultural district. But because Too many migrant workers move in or too much tourism development, making the neighborhood and the way of life

3.The continuation and development of folk activities

Historical district is originally a living area, it can show a variety of life scenes, activities. The reconstruction and activation of these activities can restore the cultural fault, and these activities have certain characteristics. Once these activities are re-activated, they can attract more people's attention and visit, and the historic district can be revitalized culturally

3.6The Types Catalytic Point

In Small Town Historic

Districts

Based on the above analysis of catalyst theory, I found that every element in the historic district of a small town could become a potential catalytic point, and I have my own standard for the classification of catalytic points.I will use the concepts of “physical” and “non-physical” to identifying the type of potential catalytic point.Physics is divided into buildings (historical buildings, original buildings, new buildings), public Spaces (squares, building gray space, lane), and structures(sculpture, landscape sketch, memorial arch).

3.6.1 Building

3.6.1.1 Historic building

After the issuance of Venice charter in 1964, the concept of historic buildings expanded to include a vast range of buildings with different characteristics and values. The word historic refers to anything famous or important in history. (Oxford Dictionary), There are various definitions for the historic buildings, the English Heritage Community defines the historic buildings as follows (the Listed buildings, which include any building or structure had historic and architectural interest, situated in the context and in the conservation areas, the buildings with especial local interest, that constituted designing considerations as an active elements within urban regeneration schemes, and the buildings with historic and architectural interest within natural distinctive areas and world heritage sites. 40

Historic buildings, as part of the cultural heritage, provides huge resources that can play an important role in achieving cultural distinctiveness, and act a catalyst role in sustainable urban development projects.Historic buildings require depending certain interventions in order to activate their catalytic role.

The catalyst intervention types are varied within different projects. It's possible to

40 _{English Heritage, (2002) "Building Regulations and Historic Buildings- balancing the needs for energy conservation with}

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depend one type or more from these interventions within historic building/ or buildings, which could be applied on the level of the historic building itself or within its context, it could be physical or nonphysical, and are generally includes

Functional intervention represented by restoring the original use or adaptive reuse. The importance of adaptive reuse method arise in confronting the problem of negligence and detachment which the historic buildings suffer from, and ensuring both the maintenance of the urban vitality and continuity the traditional character of the city. The restoration of the building original use is the preferred option to reuse, although owing to the change in the economic chances, an approach to find new uses has been appeared which are compatible with nature of urban context and this depends on (building nature, type, location, original use)41

Formal intervention, includes two types. The first one represented by restoring the historic building (as a whole or only the façade within façade retention method which depends on some cases that demand change in the building interior while conservation its façade, although some consider this approach causes deception but it has economical goals and role in conservation the city visual integrity and its traditional character) while the second one is represented by rehabilitation and adding new contemporary elements within the building itself and its surroundings. These contemporary additions whether being contradicted or confirm to the historic building form, work on enhancing the value of historic building to play its significant role in providing a positive future for the context and supporting the economy in a way insures the continuity of the historic center and especially rehabilitation the historic buildings, adding a new layer to the cultural heritage for the future generation. This type of intervention play a special role in adding new uses and contemporary investments within urban centers.42

Historical district is not only a collection of buildings, but also a living space with time dimension. It is the result formed through the development of "historical dynamics" and will continue to develop. Blind adherence to history will only bring history to a standstill. Historical districts should get rid of the shackles of the past and seek for organic adaptation and adjustment of themselves43

3.6.1.2New Building

The insertion of new buildings in the historic district has always been the focus of conservation and renewal. Architecture is not only a material unit, but also a carrier of urban culture. Excellent new architecture should also become part of the futurebuilding heritage. The inheritance of historical districts should be flexible. It should not only grasp the effective conservation of historical values, but also consider the appropriate renewal beyond the existing history. Historical buildings and new buildings are not the two sides of absolute opposition, but the relationship of unity of opposition.For example, new building materials and structures are used to express the characteristics of traditional buildings, and heterogeneous buildings echo with new characteristics. Attached to the local cultural characteristics of the

41 _{Bridgwood. L & Barry, L. (2009) "History, Performance and conservation", vol. 5, Taylor & Francis, USA and Canada, 1st}

print. P305-306

42 _{Bee, Steven, (2006), "Shared Interest – Celebrating investment in Historic Environment", English}

Heritage, p3-4

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guardian, this recruitment is a living guardian. 44

Therefore, to a certain extent, guarding and recruiting are unified. Historic buildings are the foundation of historic districts, and new buildings are the embodiment of vitality and new development of historic districts. Whether the new building is suitable or not determines whether the new building can be a catalyst to revitalize the historic district of the small town

3.6.2 Public Space

Public spaces are a fundamental feature of cities which increase liveability by encouraging everyday activities as well as special events such as festivals and, as a result, increasing social interaction. They represent sites of sociability and face-to-face interaction, and at the same time their quality is commonly perceived to be a measure of the quality of urban life. Ideally they are places that are accessible to everybody and where difference is encountered and negotiated45

Public spaces can be treated as ‘locales’, settings in which social relations and a sense of place are constituted46

Public spaces are all places publicly owned or of public use, accessible and enjoyable by all for free and without a profit motivePublic space takes many spatial forms, including parks, the streets, sidewalks and footpaths that connect, playgrounds of recreation, marketplaces, but also edge space between buildings or roadsides which are often important spaces for the urban poor and in many contexts beaches are also public spaces. This does not mean that all public spaces are “open spaces” – a library, a school or other public facilities are also public spaces

In the historical districts of small towns, I mainly select the street, square and node for discussion.

3.6.2.1 Square

A square is a large area, especially in a city. It is the hub of urban roads and the space where people carry out social activities or traffic activities such as politics, economy and culture. It is usually the place where a large number of people and traffic flow gather and disperse. In the plaza or its surrounding general layout of important buildings, often can focus on the expression of the city's artistic appearance and characteristics

In the《 aesthetics of streets》, Yasuhiro Ruhara 47_{believes that the square is a city}

surrounded by various constructions in the city.The city space. A square worthy of its name should have the following four conditions in space composition

1.The boundary line of the square is clear and can become a "figure". It is better for the boundary to be the outer wall of the building, rather than the wall merely

44 _{Liu Xiaohui，06-2018，Guarding the Old and Accepting the New: Strategies Research on Embedding New Buildings in}

the Historic Districts: Thinking About the Design Competition of Jianghanguan West Corner Project

45 _{Canter, D. (1977), The Psychology of Place. London: Architectural Press Young, I.M., 1990. Justice and the Politics of}

Difference. Princeton University Press, Princeton, NJ.

46 _{Eyles, J., Litva, A. (1998), Place, Participation and Policy: People in and for Health Care Policy. In: Kearns, R.A., Gesler,}

W.M. (Eds.), Putting Health into Place: Landscape, Identity and Well-being. Syracuse University Press, Syracuse, New York, pp. 248–269.

47 _{Yasuyuki ruhara (1918 -- 2003), a famous contemporary Japanese architect, published 《Street Aesthetics》 and}

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districting the view.

2. with good enclosed space

3. The ground pavement covers the boundary of the square, and the space is clear. The surrounding buildings have a certain unity and coordination, with a good proportion of width and height.

In a small town, the square can be divided into four spatial levels according to the degree of gathering vitality, which are the node of the entrance square connecting the town, the square where people flow, the secondary entrance square facing the streets and the corner square serving the residents

3.6.2.2 Street

In a city, the street must be sovereign. The street is the room agreed upon by mankind, the social room of the community, the gift given to the city by the owners of the houses on both sides for daily life, and the sky is its ceiling." So says Louis kahn48_。

In addition to a certain traffic function, the street space of the historic district can also give people a visual feeling. Therefore, the remodeling and activation of the street space should first focus on the visual effect of the space, and then pay attention to the diversity of functions to ensure the lasting vitality of the district. In addition, the historical and cultural districts of the appropriate pedestrian street renovation, not only to increase the accessibility of the district, but also to give visitors a sense of pleasure.Narrow lane ways among buildings in many small towns and historic districts have not only become the traffic space for people to maintain their daily life, but also the winding and meandering lanes have brought the harmonious atmosphere and the sense of belonging among neighbors

In 《theory and practice of urban space》, collier listed many types of urban space combination ways. By referring to the interpretation of street space form, he summarized the composition of street space form into the following four elements: 1.Street space is basically linear

The basic line of the street space depends on the location and orientation of the street in the urban road network, as well as the basic basis of the interface on both sides and the location of the street. The chessboard type street system in the old city presents the following three basic lines

· general linear, linear straight line line is always the most common street line, traffic street, residential street, cultural commercial street, comprehensive commercial street, tourist street, residential street jiefang road

· linear cross-view type, generally larger in scale, serving as the traffic street, tourist and residential street of the urban landscape axis

· ordinary folding shape, naturally formed, with a turning point but relatively gentle, a rare linear residential street in the old city

2.The relationship between street building interface and street boundary form

The street building interface directly affects the enclosing form of the street space. The continuous, concave and gray space of the building interface can shape the street boundaries of different forms

3.Street corner spatial form

Street corner spatial form determines the spatial form of two or more streets, and influences whether people are willing to enter the street, which plays a key role in the active atmosphere of the street space. The intersection of any two streets in the old city will form a cross of "ten" or "d", which is not only an important junction of

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traffic convergence, but also a busy and lively place in the streets, especially a cultural commercial street, with higher requirements for the construction of the space at the intersection. Street entrance, different corner shape can create a different degree of enclosed street space

4. Spatial sequence of streets

The spatial sequence of the street reflects the organization rules and internal order of the street space. A good street, not simply flat and disorderly but rich in variety, leads people to use each street with different expectations. When people walk in the street, they will not get tired and lose their way. It is easy for people to build psychological cognitive map, form a clear sense of direction, and then form a sense of place in the street. Street space sequence is the result of interaction between street line space and node space. Considering the starting, turning and closing of the whole space, the space forms a sequence of beginning, transition, climax and ending.

3.6.2.3 Architectural Gray Space:

In terms of architectural concept, "gray space" refers to a transitional space between indoor and outdoor, that is, a space that is half indoor and half outdoor. This architectural concept of "gray space" was put forward by one of the three famous Japanese architectures, Mr. Kurokawa. In colour respect "gray space" ash, it is black and white transition color; gray space refers to the concept of space in architecture, which belongs to transitional space. The existence of gray space in the architectural space can erase the boundary between the interior and the exterior of the building in a certain visual perception. It not only expands the interior space of the building in terms of vision and perception, eliminates the estrangement between the interior and the exterior, softens the boundary lines, but also makes the interior and the exterior of the building become an organic whole. The coherence of space and the unity of design create a consistent building between interior and exterior. From the perspective of wholeness, the design of interior and exterior of space can be understood as the environmental design from the interior of space, which gives people a natural and unified overall feeling.

Based on the types of construction, thisthesis summarizes several common types of gray space: architectural gray space and self-built gray space sketch gray space.

1 Elevated ground floor:

architectural gray space, that is, a kind of gray space formed by the addition and subtraction of building districts, the concave-convex facade form, and the change of space between buildings. As Le Corbusier said, the stilts allow people to get more sunlight and air

This kind of gray space has both indoor pleasant atmosphere and outdoor comfort, and is easy to reach, high degree of use, but also can introduce greening and public facilities, rich gray space function use.

2 Facade is revealing:

Elevation relative to protrude the structure of the construction as a whole and extends outward form, we can below without any support, more than in the small towns in the historical district in the south to revealing the roof, balcony is revealing, the area affected by the climate characteristics of abundant precipitation, districts form a unified and distinctive white wall HeiWa, slope roof tile on the top of the residential style. The eaves with different forms have become the most typical facade overhanging space -- eaves are formed by eaves, tiles and water drops, which are not only practical in draining rainwater and protecting wood ridges, but

Conservation and revitalization of Huizhou small towns based on the theory of urban catalyst. The West Street historic district of Keenmun town in Huizhou as an example