Abstract
Urban renewal and the built environment have become two of the hottest topics in urban planning studies. Although existing literature has started to examine both of them from different perspectives, a comprehensive review with a bibliometric analysis is necessary to fully reveal the association between them. To overcome these gaps, this paper critically reviews the literature on urban renewal and the built environment and proposes a novel research framework to systematically understand the relationship between them. Based on 155 articles which were published between 2001 and 2020 collected from the Web of Science Core Collection Database, a bibliometric analysis offers the overall development and trajectory of the existing research, and a critical review fully analyzes the relationship between the two topics from three perspectives: main categories of urban renewal, multiple stakeholders, and economic, social and environmental development needs. To better clarify the interaction mechanism between urban renewal and the built environment and guide further research in this area, a future research agenda is also provided.
With the acceleration of urbanization worldwide, many cities have been facing problems such as urban sprawl and the decline of central urban areas. Urban renewal has become a typical approach to reversing urban decline, gradually replacing the traditional mode of incremental urban development. Current research on urban renewal covers various aspects such as economic development, social sustainability, and environmental improvement, but these issues are inseparable from an important concept: the built environment (Miltenburg et al. 2018; Zuk et al. 2018). Couch, Sykes, and Börstinghaus (2011) define urban renewal as encompassing the cleanup of old slums, the reconstruction or rehabilitation of physical forms, and heritage preservation. Therefore, the improvement of the built environment is an essential objective of urban renewal.
There are various types of built environment with different physical and spatial characteristics for urban renewal, such as slums, brownfields, vacant housing, and heritage (Rauscher and Momtaz 2015; Zhong and Chen 2017). Low-quality, dilapidated, and abandoned buildings or facilities beyond repair are usually demolished and reconstructed on site, which has been regarded as the major form of urban renewal for a long time. However, irrational demolition and reconstruction may lead to huge construction waste, serious dust and noise pollution, and incompatible built environment. To solve this problem, the existing buildings or facilities whose life expectancy are evaluated to be not finished and still usable to cities, investors, or local residents could be rehabilitated (Douglas 2006), and built heritages with high cultural, social, and architectural value should be conserved. Therefore, urban renewal needs to be well coordinated with the surrounding built environment, including buildings and facilities, to better achieve sustainable urban development.
The implementation process of urban renewal projects involves multiple stakeholders, such as the government, private sectors, and residents, and they have their own interests and preferences, and their impact on the built environment varies in both nature and degree (Zhuang et al. 2019; Wang et al. 2021). For example, for different types of urban renewal, government policy formulation (Weber 2002), private sectors’ activities in demolition and investment (Adair et al. 2007; Kriese and Scholz 2011), and residents’ satisfaction (Berry, Seiders, and Grewal 2002) have different impacts on the built environment, which increases the complexity of the association between urban renewal process and the built environment. In addition, existing literature demonstrates that urban renewal aims to achieve economic, social, and environmental development needs through the improvement of urban fabric (Chan and Lee 2008a). These development needs determine the purpose and specific implementation measures of urban renewal to a certain extent, and thus form interactive relationships with the built environment, which is also a motivation of this review paper.
Although previous research has looked into the built environment in urban renewal, it is mostly limited to a single topic, and a research framework integrating different categories, stakeholders, and objectives of urban renewal is needed. The literature review aims to provide a systematic research framework related to three main dimensions (i.e., different categories of urban renewal, multiple stakeholders, and various development needs), which makes contributions to the provision of more comprehensive views on the relationship between urban renewal and the built environment for researchers and practitioners in the planning field. To be specific, the proposed framework is helpful for researchers specialized in urban planning to better explore appropriate theories and directions for future research, and further conduct in-depth work to fill the research gaps of existing studies. For planning practitioners, this framework helps formulate more practical and feasible plans or policies by identifying the relationship between different types of urban renewal and the built environment, reducing actual conflicts between multiple stakeholders, recognizing various development needs, and solving a variety of problems in the future.
Method
Based on the purpose of stand-alone reviews, this review paper attempts to address the inter-relationship between urban renewal and the built environment. We follow the procedures and rules proposed by Xiao and Watson (2019) to conduct literature retrieval, and the details are described as follows.
Literature identification. All documents retrieved in this review are located through the Web of Science Core Collection Database. As the theme of this paper, urban renewal and the built environment are of priority when setting the search rule. Although the keywords “urban renewal,” “urban regeneration,” “urban revitalization,” “urban redevelopment,” “urban rehabilitation,” and “heritage preservation” are used in different scale, they share a similar meaning with the aim of solving the problem of urban decline, and their definitions are given in Table 1. Generally, urban renewal, urban regeneration, and urban revitalization are regarded as the same concept with a relatively large research scale by scholars around the world due to their similar meanings. Urban redevelopment, urban rehabilitation, and heritage preservation are three important concepts and categories involved in urban renewal (Zheng, Shen, and Wang 2014), and they are all included in the keywords search rule.
Definitions of Related Concepts of Urban Renewal.
To consider the built environment as comprehensively as possible, the search rule setting for the built environment needs to include its key elements. This paper follows the definition of the built environment given by Amuda and Berkowitz (2019), which refers to the physical characteristics of urban areas, including housing, facilities, streets, and open spaces. To be specific, in addition to buildings, like housing (Wang and Cao 2017), the built environment also includes facilities (Kajosaari and Laatikainen 2020), streets and roads (Stoker et al. 2015), open spaces like parks and green spaces (Koohsari et al. 2015).
The keywords search rule of this paper in Web of Science is TS = (“urban renewal” OR “urban regeneration” OR “urban revitalization” OR “urban redevelopment” OR “urban rehabilitation” OR “heritage preservation”) AND TS = (“built environment” OR build* OR house* OR housing* OR facility OR facilities OR street* OR road* OR open space), where “TS” denotes the Topic Search criterion including title, abstract, author keywords, and keywords plus, and “*” represents the related terminology of a word. With this search rule, 2104 records were initially found. Then, we only retained the records with a publication time span from 2000/01/01 to 2020/12/31, in the language of English and the document types of peer-reviewed articles, excluding conference proceedings, book, news, and editorials, and finally 1463 records were returned.
Screening for inclusion. We read the titles and abstracts of the 1463 journal articles to further evaluate their relevance to research theme—the relationship of urban renewal and the built environment. Two groups of literature were excluded, one group not discussing the changes of the built environment in the context of urban renewal, and the other group only studying urban renewal separately without mentioning the built environment. Furthermore, as this review aims to serve the planning field, several irrelevant fields such as art, business, communication were excluded. After that, 396 articles related to the relationship between urban renewal and the built environment were selected.
Quality and eligibility assessment. The assessment of quality and eligibility was performed by skimming through the full-text of the 396 articles. We excluded articles that focus on only one of the two topics (i.e., urban renewal or built environment) but lack an explicit association to the other topic, e.g., only mentioning the issues of one of the two topics as a policy implication. In addition, several documents that have been published for many years but with low citation counts were excluded to ensure the quality and eligibility of the literature reviewed, and some documents published by reputable publishers were retained.
Bibliometric Analysis
Overview
Using the above literature retrieval method, we finally retrieved 155 articles. Figure 1 visually displays the number of papers published and citations in related fields from 2001 to 2020, which helps readers to easily understand the popularity changes in topics related to urban renewal and the built environment. The amount of related literature in the Web of Science Core Collection Database has increased significantly and showed a continuous upward trend since 2014 and peaked in 2020. The number of citations increases sharply from 2 in 2002 to 1,057 in 2020. These counts indicate that studies on the relationship between urban renewal and the built environment become increasingly popular.
Number of selected papers and literature citations from 2001 to 2020.
Co-Occurrence Analysis
The keyword co-occurrence network map is created based on 831 keywords of the 155 articles, and 86 keywords are filtered by the threshold of three occurrences as shown in Figure 2. VOSviewer software is used to divide all keywords into five clusters, which are red, green, blue, purple, and yellow, respectively. The network of five clusters represents the relationships between three categories of urban renewal (i.e., urban redevelopment, urban rehabilitation, and heritage preservation) and the built environment, and several factors mainly referring to factors of stakeholders and development needs that influence the relationships.
Network visualization of co-occurrence of keywords.
Specifically, the red cluster mainly focuses on multiple aspects of the implementation process of urban redevelopment projects such as gentrification and displacement; the green cluster highlights urban rehabilitation issues such as specific implementation patterns and the role of government; the blue cluster represents an important theme: heritage preservation; both purple and yellow clusters presents some important factors concerning stakeholders and development needs that may have a direct or indirect impact on the relationship between urban renewal and the built environment.
Critical Review
Drawing on the results of the bibliometric analysis, the research framework for the critical review is developed and shown in Figure 3. Based on existing studies such as Couch, Sykes, and Börstinghaus (2011); Liu, Wang, and Wang (2019), urban renewal improves the built environment through three main actions: urban redevelopment, urban rehabilitation, and heritage preservation, which are quite different in terms of purposes, contents, and results of the implementation. As a result, the differences in the built environment before and after urban redevelopment, urban rehabilitation, and heritage preservation are clarified, respectively.
Research framework for critical review.
Various stakeholders such as the government, private sector, and residents in the implementation process may influence the built environment of urban renewal projects according to their own interests or preferences, which may conflict with each other (Xiong et al. 2015; Wei et al. 2016). Several items in Figure 2 reflect the important role of stakeholders and a section of the critical review focuses on the impact of stakeholders on urban renewal and the built environment.
In addition to stakeholders, some development needs in urban renewal projects are also considered. The nodes in Figure 2 show that the concept of sustainability in urban renewal is of wide concern. Sustainable development is the goal pursued by urban renewal projects to achieve specific economic, social and environmental development needs through the improvement of urban fabric (Chan and Lee 2008b). Thus, we review the interactive relationship between economic, social, and environmental development needs and the built environment.
In sum, the critical review is conducted to clarify the relationship between urban renewal and the built environment from three perspective: three categories of urban renewal, multiple stakeholders and development needs in urban renewal.
Urban Renewal’s Three Categories
Urban redevelopment
Urban redevelopment changes the appearance and use of the original built environment completely. To clear deteriorating urban areas like slums and brownfield site (Collins and Shester 2013), rebrand spaces (Patel 2014), gain the revenue of land sales (Wu 2020) or achieve other purposes, urban redevelopment projects are conducted by many cities in the stage of urbanization. The principal means for urban redevelopment are demolition and reconstruction (Liao and Bao 2014); to be specific, these demolish traditional communities or underused buildings and facilities, redesign and reconstruct the improved built environment (Nagel 2002; He and Wu 2005).
Different viewpoints exist in the literature regarding whether the built environment would be improved through complete redevelopment. On the one hand, a large and growing body of literature suggests that the built environment in this process experiences a series of positive improvements (Lai, Wang, and Lok 2017). The deterioration of the built environment is often accompanied by low-quality housing or commercial and industrial buildings (Sousa 2006), underutilized, insufficient and abandoned facilities (Lee and Mohai 2012), congested traffic (Tong et al. 2018). To tackle with these problems, urban redevelopment can be used to create orderly, comfortable and safe built environment consisting of standard housing with legal property rights and higher quality (Mizuuchi and Jeon 2010), multiple types of infrastructure (Williams et al. 2019), recreational facilities (Atkinson, Tallon, and Williams 2019), and accessible transportation (Semenza 2003).
On the other hand, some scholars outline the negative effects of redevelopment on the built environment. Several large-scale redevelopment projects are implemented with disorderly demolition and reconstruction as the main methods (Ho et al. 2012; Shen, Yuan, and Kong 2013). The mixed garbage (e.g., stones, concrete, and chemicals) generated in the demolition process occupies a large amount of space and requires huge human and financial resources to classify it (Yuan and Shen 2011; Lu et al. 2017), and some countries are not doing nearly enough to recycle building pollutants (Lu and Yuan 2011). Moreover, Shen, Yuan, and Kong (2013) contend that urban redevelopment will shorten the life cycle of buildings, mainly due to premature demolitions and failure to follow principles of sustainable development.
Many studies have documented urban redevelopment in a specific city through case studies, which helps analyze the transformation of the built environment using different types of redevelopment projects in various cities around the world. Table 2 lists the differences in the built environment before and after four representative urban redevelopment projects in the existing literature. To be specific, the first and second projects are the redevelopment of slums and brownfields, respectively; the third project mainly focuses on residential redevelopment and the last is a multi-used, multi-zone integrated redevelopment project.
Urban Redevelopment Projects Mentioned in Literature Examples.
Urban rehabilitation
In contrast to urban redevelopment, which is a radical renewal mode, urban rehabilitation is regarded as a milder and sustainable strategy to improve the decaying built environment in the old urban center (Pérez 2010). In the process of global urbanization, a large number of demolitions and new construction have caused many negative effects on the city, such as waste of infrastructure, overconsumption of resources (Silva and Ramos 2011), vacant housing or community, discontinue urban development (Virtudes 2019). To foster economic, social and environment sustainable development, urban redevelopment has been gradually abandoned, and rehabilitation has become one of the most popular renewal strategies instead (Yung, Chan, and Xu 2014). Weber (2002) and Yau (2015) both propose that urban rehabilitation could provide economic value to local development through the improvement of the built environment.
Generally, the built environment transformed by urban rehabilitation consists of existing buildings that need and can be restored, and physical intervention is implemented on them to meet the requirements of structure, quality, and function (Cruz and de Brito 2015; Sing, Love, and Liu 2019). In other words, urban rehabilitation often occurs on existing buildings whose life expectancy are evaluated to be minimally at new standards and still have value to cities, investors, or residents (Douglas 2006; Kohler and Yang 2007). Many cities or districts have formulated laws and regulations that include detailed built environment indicators to determine corresponding urban rehabilitation measures or evaluate the success of the rehabilitation projects. According to Nel·lo (2011), the Catalan Neighborhoods Act, an act of urban rehabilitation, mentions that the built environment indicators should include provision or improvement of public spaces, green areas, common building elements like lifts and roofs, services, information technology, and so on. Particularly, Silva and Ramos (2011) highlight the importance of the recovery of key buildings representing the image of local communities or cities. To sum up, urban rehabilitation fully recovers the original built environment in both the public and private domain, while preserving the use of buildings.
Heritage preservation
Heritage endows the built environment with high historical and cultural value, which is irreplaceable and unrecoverable. Heritage preservation is increasingly being incorporated in the renewal plans of many cities around the world (Wang and Aoki 2019). There are many types of heritage according to varied classification standards such as tangible heritage, intangible heritage (Munjeri 2004), built heritage, and culture heritage (Tweed and Sutherland 2007). In this paper, the term “heritage” shares the similar meaning with Yung, Zhang, and Chan (2017), which refers to the monuments, historical buildings, street blocks and other urban built environment elements with high cultural, social, and architectural value. These sites usually play significant roles in reflecting the local cultural and historical roots, triggering a strong emotion of place attachment, representing the integration of urban religious, economic, and social image (Alonso González 2017). Therefore, preserving the urban heritage sites is essential for maintaining and developing the urban specific characteristics and improving the physical quality of the built environment.
Different cities have adopted various types of policies and practices for heritage preservation in the process of urban renewal. Mehanna and Mehanna (2019) summarize the most important policies dealing with heritage sites: redevelopment, conservation, rehabilitation, urban infill, and revitalization. Most cities in Western world regard heritage preservation as a common and indispensable method and built heritage should be maintained and protected successfully (Zeayter and Mansour 2018). Strange and Whitney (2003) comprehensively discuss the practices and changing roles of heritage preservation in the UK around four themes: reorientation, sustainability, planning, and governance. Ferilli et al. (2017) examine three cases of culture-led urban renewal in Canada, Australia, and Italy, and note that culture can play a unique role in the preservation of heritage. Nevertheless, some non-Western cities argue about this conservation mode or even adopt the demolition method. Said, Aksah, and Ismail (2013) claim that many historic cities in Southeast Asia, particularly in Malaysia, currently are facing the problems of excessive commercialization, poor architectural design and indifference of culture without safeguarding urban built heritage. Zhong and Chen (2017) analyze three heritage projects and find that in China, there is often a conflict between property development and heritage preservation and less attention has been paid to urban built heritage.
Multiple Stakeholders in Urban Renewal
Government
Urban renewal has been regarded as a type of urban policy that is a typical function of central and local governments (García 2004). Urban renewal can be difficult in a completely liberalized market and government intervention can be necessary to foster orderly renewal (Cruz and de Brito 2015). The government plays a critical role in the process of urban renewal, which directly influences urban layout and thereby regulates the built environment to a certain extent.
Existing literature has devoted considerable attention to government's functions and practices on the three types of urban renewal. First, most redevelopment projects initiated by the government have been criticized because gentrification, the process of transition from indigenous low-income groups to the middle class with adverse effects from displacement, is likely to happen (He and Wu 2005; He 2007). For instance, the government, seeking economic benefits, may convert low-income residential to more profitable high-income residential, commercial and office uses (Wu 2016). Second, although redevelopment is always profitable to the government, the government still may encourage urban rehabilitation projects and promulgate corresponding policies considering sustainable development (Sing, Love, and Liu 2019). Portugal has established an institution named Urban Rehabilitation Societies whose purpose is to promote the rehabilitation of old city centers (Pipa, de Brito, and Cruz 2017). In addition, urban rehabilitation has been incorporated into local detailed planning by more and more cities to promote the renaissance of an integrated urban built environment (Virtudes 2019). Third, many studies describe the irreplaceable role of the government in heritage preservation (Munasinghe 2005). Most policymakers believe that heritage can stimulate stable and positive development of the local economy through tourism or creative industries (Cesari and Dimova 2019) and make local residents respect public goods (Meskell 2012). Heritage-led renewal projects initiated by the government can protect the original built environment well protected with the formulation of specific conservation policies (Dogruyol, Aziz, and Arayici 2018).
Overall, existing studies have highlighted the role of the government in urban redevelopment, rehabilitation, and heritage protection. However, with quantitatively driven public policy becoming more popular, scholars rarely evaluate and predict the impact of multiple factors such as gentrification, local identity, and heritage on policy making and how policies affect the built environment.
Private sector
The private sector mainly refers to urban renewal's developers or investors (Zheng, Shen, and Wang 2014), which is another main player in urban redevelopment and rehabilitation (Li, Kleinhans, and van Ham 2018), as it is usually the primary project implementer, especially for market-oriented renewal projects (Wu 2004). The demolition, architectural design, and construction of urban renewal projects by developers have a considerable direct impact on the built environment (Kriese and Scholz 2011). Previous studies have mostly criticized developers for disorderly demolition and reconstruction of buildings (Ho et al. 2012; Lu et al. 2017), but few of them have explored how to make developers play a positive role in improving and protecting the built environment in the process of urban renewal.
In addition, sufficient funding is essential to enable the built environment within urban renewal projects to include improved infrastructure and higher-quality buildings. Funds for urban renewal in many countries or regions come almost solely from the government (Hsu and Hsu 2013). Meanwhile, private capital has been increasingly invested in urban regeneration projects. Turnbull (2017) describes cooperative land banks, established by some private organizations, that can provide self-financing for new urban infrastructure and services, thereby reducing the need for public investment and alleviating the government's burden during the implementation of urban renewal projects.
Public-Private Partnerships (PPPs) have been widely discussed in both academia and industry. PPPs defined as any type of cooperation that combine public and private skills or resources can be applied to many types of projects, such as health facilities and schools (Ng, Wong, and Wong 2012). Local government is increasingly using PPPs to implement urban regeneration projects (Sagalyn 2007; Bourguignon 2013). Morano and Tajani (2017) involve private investors in planning and decision-making concerning urban renewal projects and analyze the financial sustainability of these projects from the perspective of private investors. Since PPPs integrate the various advantages of public and private investment (Hsu and Hsu 2013), it is necessary to actively explore the mode of PPPs in urban renewal in the future to create a better built environment.
Residents
Residents are the end users of the community that has experienced urban renewal. Differences in the built environment caused by urban renewal will directly affect the lives of residents and, in turn, residents’ willingness or satisfaction will also affect the decision of urban renewal projects (Adriaanse 2007; Du et al. 2020). Many studies have analyzed the impact of gentrification, as a possible result of urban redevelopment, on the lives of original residents. In terms of the built environment, gentrification provides decent housing, accessible transportation, and clean green spaces, which is regarded as a positive urban strategy by government and public sectors (Zhang et al. 2014; Verkasalo and Hirvonen 2017). However, for original residents, this could bring about displacement, community segregation, and homelessness, because most of them cannot afford the fast-growing high housing prices and living costs due to the improvement of the built environment, which results in social unsustainability (Atuesta and Hewings 2019; Lukens 2020).
Whether residents’ willingness and satisfaction are fully considered is a key factor in measuring the success of urban renewal projects. The built environment is a main aspect affecting residents’ willingness to live in the community (Jalaludin et al. 2012; Ibem and Aduwo 2013). High-quality housing and facilities in the community can greatly enhance resident satisfaction (Skevington, Lotfy, and O’Connell 2004). Mohit, Ibrahim, and Rashid (2010) and Fang (2006) point out the positive correlation between the size of housing units and resident satisfaction with the urban renewal process. Guo, Li, and Wang (2018) reveal that the quality of the community facilities and soft resources, including education, healthcare, shopping, and transportation in the old community, affects residential satisfaction. It is worth noting that most studies only focus on the willingness and satisfaction of the residents who still live in the original community, while ignoring the residents who may have had to move from their original home and faced displacement due to gentrification.
Development Needs in Urban Renewal
Economic development needs
A harsh built environment cannot contribute to the local economic development and can even lower the income and consumption levels of locals, causing companies to lay off employees or go bankrupt, which is inconsistent with economic sustainability (Chan and Lee 2008b). On the contrary, urban built environment with better physical condition of buildings and infrastructure can solve these economic problems and achieve economic sustainability (Kylili, Fokaides, and Jimenez 2016; Zheng et al. 2017).
To obtain economic benefits from the improvement of the built environment, many urban renewal projects are conducted to stimulate urban economic growth (Ryberg-Webster and Kinahan 2014). Housing is one of the most important parts of the built environment and it is heavily affected by economic factors. Gotham (2001) contends that although city leaders in the United States often use urban renewal as a tool to fight against substandard housing, the government lack sufficient funds to improve housing and clean up slums due to the economic instability. To solve it, collaborations between real estate developers and urban planners have brought a stronger flow of private capital into urban renewal areas (Zipp 2013).
Many scholars specializing in urban renewal have studied the economic factors affecting decision-making in urban renewal projects, as shown in Table 3. In contrast, Zhou, Zhou, and Liu (2017) conduct more comprehensive research integrating many types of economic factors, such as cost, investment (risk and reporting), and market issues, all of which play important roles in projects’ economic sustainability.
Previous Studies of Key Economic Factors in Decision-Making of Urban Renewal.
Social development needs
Social development needs cover many aspects of society, including social groups, social interactions, sense of place, national laws, and cultural identity (Ghahramanpouri, Lamit, and Sedaghatnia 2013; Ročak, Hospers, and Reverda 2016). In recent years, lots of studies have started to explore the relationship between built environmental design and social development to achieve social sustainability in urban renewal. Chan and Lee (2008a) point out that a harmonious built environment, available open spaces and facilities are important factors that can improve social sustainability. Similarly, Säynäjoki et al. (2014) assert that a place that meets social sustainability should be built and planned well.
Compared with urban rehabilitation and heritage preservation, urban redevelopment is most likely to cause a series of social problems. Although some scholars believe that demolition is the main method to eliminate the rent gap, gentrification may occur through redevelopment projects (Shin 2009). The research on gentrification from the perspective of social inequality has been a hot issue discussed by academics. There may be housing inequality induced by gentrification between original residents and new residents. Most of the original residents are displaced due to lack of affordable housing, and the new residents with higher socio-economic status live in newly built standard housing (Ha 2004). The increasing gap between rich and poor can cause or aggravate a series of social conflicts, trigger riots and even wars (Solana-Solana 2010). In addition, the price of redeveloped housing and land will experience increasing growth due to the improvement of the built environment, which will directly reduce the housing affordability of existing residents (Guerrieri, Hartley, and Hurst 2013). Most existing literature focuses on why and how gentrification occurs and the social problems it causes, while few studies center on how to design the built environment to solve these problems through urban renewal.
For some special social groups, sustainable social development requires that the built environment should also be designed equitably. For instance, aging is an important social factor in urban renewal and also a hot topic in current research. Open spaces, parks near housing, and convenient leisure space contribute to active aging (Lau, Giridharan, and Ganesan 2005). Specifically, design criteria for public open spaces suitable for the elderly have been discussed in many studies, with the main concerns falling into three categories: (1) physical setting, (2) community features, and (3) transport, location, and mobility (Temelová and Dvořáková 2012; Yung, Conejos, and Chan 2016). In addition, recognizing the importance of an accessible built environment to social equality for those people with disabilities and other vulnerable groups has always been positive in the process of urban renewal. Osman, Bachok, and Bakri (2015) analyze the facilities available for vulnerable and disadvantaged groups and the benefits of providing an inclusive built environment for these groups, including health care benefits, vocational and academic training in special schools and institutions, financial assistance, equipment assistance and work arrangements.
Environmental development needs
Environmental development needs include not only increasing the quality of the environment but also solving the environmental problems (Dennison 2008). Urban renewal is a tool to meet these environmental needs through environmental design. Yildiz, Kivrak, and Arslan (2017) summarize that several design elements studied by existing research to solve environmental problems: the usage of sustainable built resources, transportation design, green and open spaces, and waste recycling. At any stage such as demolition, construction, and repair of buildings, the use of sustainable resources is a key measure of whether the project meets environmental sustainability (Motawa and Carter 2013). To reduce the emission of pollutant gases and traffic, it is critical for the traffic design of urban renewal zones to minimize environmental pollution by providing sidewalks and bicycle lanes, and restricting the use of motor vehicles (Giles-Corti et al. 2016). Green and open spaces play an important role in improving the quality of air and water, reducing urban noise, and making the microclimate better (Dizdaroglu and Yigitcanlar 2014). Finally, as large-scale urban redevelopment projects inevitably produce a lot of construction waste during the process of demolition and construction (Yuan 2017), it is important to reduce and recycle these wastes in redevelopment. Instead, urban rehabilitation and heritage preservation can minimize waste as much as possible (Yildiz, Kivrak, and Arslan 2017). Although current research has discussed which design elements of the built environment are related to the needs of environmental development, the degree of importance of these elements to environmental development lacks quantitative analysis.
Discussion
The existing research demonstrates that urban renewal and the built environment interact closely with each other in numerous ways. We have examined the differences in the resulting built environment due to each of the three categories for urban renewal, the impact of stakeholders in urban renewal on the built environment, and the interactive relationship between economic, social, and environmental development needs with the built environment. This section discusses the complex relationship examined by previous studies and provides a future research agenda.
Table 4 summarizes the relationship between three categories of urban renewal and the built environment, the role of stakeholders and development needs based on existing literature. Different urban renewal categories use different built environmental designs, and government intervention plays the most important role in the entire process of urban renewal, including planning, investment, and supervision. Urban rehabilitation and heritage protection more tend to meet development needs and achieve sustainability.
The Relationship of Urban Renewal and the Built Environment Studied Within the Existing Literature.
The research gaps and potential directions for further research are provided based on the critical review. The future research agenda shown in Figure 4 is developed by grouping the three main categories of urban renewal, which provides a roadmap for future exploration of researchers in the field of urban studies and planning. Hence, the implications are also elaborated from the perspectives of urban redevelopment, urban rehabilitation, and heritage preservation.
Future research agenda.
Urban Redevelopment
Since multiple stakeholders’ interests are quite diverse and greatly affected by urban redevelopment projects, how to promote multi-stakeholder coordination and mitigate their conflicts in decision-making about different built environmental design before project implementation has become an important research question. Three important issues are under debate: (1) what is the policy intervention's effect on the built environment of urban redevelopment and how to measure the effect quantitatively, (2) how to exert a positive role for the private sector in the process of demolition and reconstruction of buildings, and (3) how to develop a people-oriented and inclusive urban redevelopment plan that considers the willingness and satisfaction of those who might be displaced. In addition, using big data and text mining methods to answer these questions would be an interesting research direction.
In terms of development needs, as the built environment can be fully reshaped and transformed by urban redevelopment projects, how to make a redevelopment plan consistent with sustainable development is still an ongoing research question. Existing literature has discussed the redevelopment planning from a single dimension of economic, social or environmental development need. However, further research on redevelopment planning of the built environment with a multidimensional analytical perspective based on the research framework is needed. Future research could emphasize (1) quantitative work to analyze the economic effects of different built environment elements and characteristics based on solid subjective and objective data, (2) social problems of gentrification (e.g., social justice of displaced people) from the perspective of built environment restructuring, and (3) the degree of importance of built environment elements to environmental development needs, such as carbon emission reduction and energy saving.
Urban Rehabilitation
An important discussion in progress on urban rehabilitation is how to adopt a systematic governance to better revitalize the built environment. The focus of the current debate is whether top-down rehabilitation mode led by the government, or bottom-up rehabilitation mode with resident participation, or public-private partnership mode is more beneficial to the upgrade of the built environment. Specially, although discussion about public-private partnerships is in progress, how to broaden the financing channels for private capital to participate in the built environment rehabilitation sustainably and equitably in urban renewal should be further explored.
In addition, although some qualitative research suggests that moderate strategies of urban rehabilitation are favorable to meeting various development needs, there is an urgent need for quantitative economic-social-environmental assessments for rehabilitation actions on the built environment, and stakeholders should be included in the assessment system. Like urban redevelopment, quantitative work to examine economic effects of the built environment and the degree of importance of built environmental elements to environmental development, such as green retrofit of existing buildings in the process of urban rehabilitation also could be regarded as an important topic for future research.
Heritage Preservation
What heritage is worth preserving and how to implement heritage protection in urban renewal have been under debate for decades, which may cause great conflicts between stakeholders. This paper encourages a dialectical overview on heritage preservation from the perspective of the built environment. Quantitative methods can evaluate the value of urban heritage comprehensively. In addition, what roles the government and planning professionals should play have not been fully explained in existing studies. Public participation in heritage preservation is also a contested issue. Special attention should be paid to how governments and planning professionals guide the public to protect valuable built heritage instead of destroying it. As for development needs, two future research questions are outlined: (1) how to quantify economic benefits of heritage preservation and (2) what is the effect of non-physical factors such as residents’ cultural identity and memory still needs to be considered in the decision-making. Large-scale questionnaire surveys and in-depth interviews could be used to collect more representative data for empirical studies.
Conclusions
This paper provides a systematic review of existing literature on the relationship between urban renewal and the built environment, and a synthesis of key topics for future research agenda. 155 articles were selected for bibliometric analysis and critical review. A comprehensive research framework related to three main dimensions (i.e., different categories of urban renewal, multiple stakeholders, and various development needs) is developed for the critical review, which offers deeper views on the relationship between urban renewal and the built environment for researchers and practitioners in the planning field.
The main findings can also be summarized from three dimensions within the proposed framework. First, a review of existing literature reveals that the implementation mechanisms for urban renewal in various types of built environment are different, and compared with urban rehabilitation and heritage preservation, urban redevelopment has a more thorough and comprehensive impact on the built environment, which is often criticized by researchers. Second, stakeholders’ participation including government intervention, implementation and investment of the private sector, and residents’ willingness and satisfaction affects the built environment in the process of urban renewal. Third, built environmental design in urban renewal should meet development needs such as economic growth, social equality, and environmental protection.
This paper encourages researchers to address issues related to urban renewal and the built environment within the systematic framework proposed in the critical review. More in-depth investigations for different research directions listed in Figure 4 would be beneficial for more multidisciplinary convergence towards the relationship between urban renewal and the built environment, as well as more scientific and reasonable urban planning.
Footnotes
Acknowledgments
The authors sincerely thank Prof. B.S. Tang and Dr. Ivy Wong for their constructive suggestions during the paper writing.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the National Natural Science Foundation of China (grant number 72074240), the Humanities and Social Science Fund of the Ministry of Education of China (grant number 19YJCZH154), the Beijing Social Science Foundation (grant number 17GLB030), First-class Academic Discipline Construction Project of Central University of Finance and Economics (grant number 20190807-8) and Program for Innovation Research in Central University of Finance and Economics.
