Empirical Research and Optimization Strategies for the Retrofitting and Renewal of Existing Super High-Rise Buildings from the Perspective of Urbanity

Abstract

As a dominant typology of urban development and a critical component of public infrastructure, super high-rise buildings have transitioned from a speed-driven expansion model to one that emphasizes a balanced approach between development pace and quality. Within the context of urban stock renewal, numerous super high-rise buildings now face pressing needs for retrofitting to enhance their sustainability and urban integration. This study establishes “urbanity”—defined as the capacity of the built environment to foster vibrant, inclusive, and sustainable urban life—as a core evaluation criterion for assessing the retrofitting and renewal of super high-rise buildings. Based on a comprehensive literature review and field investigations, 21 representative indicators were identified, and the key factors influencing the upgrading of such buildings were determined. Subsequently, 20 super high-rise buildings in Shanghai were selected as case studies, and their urbanity performance was assessed using a fuzzy comprehensive evaluation model (FCEM). The findings reveal common challenges, including architectural homogenization, functional singularity, limited vitality in near-ground spaces, weak integration with surrounding infrastructure, and inefficient utilization of urban landscape resources. Furthermore, the study analyzes urbanity-oriented enhancement strategies implemented in the selected cases and proposes targeted improvement measures across five key dimensions: building morphology, functional configuration, near-ground space, infrastructure, and urban landscape. The research contributes to the body of knowledge on sustainable urban regeneration by providing a practical evaluation framework and actionable strategies for retrofitting super high-rise buildings. The findings aim to support more livable, inclusive, and resilient urban environments, with implications for both Chinese and global cities facing similar challenges in high-density urban contexts.

1. Introduction

The development of super high-rise buildings in China’s major cities has consistently adhered to a demand-driven approach and been supported by tangible benefits [1]. These structures maximize functional efficiency on limited land resources [2], and the resulting economic density and highly concentrated material space play a crucial role in enhancing urban comprehensive competitiveness [3]. However, with the transformation of urban environments and the evolution of urban development philosophies, a considerable share of super high-rise buildings, constrained by their intrinsic structural features and sophisticated system configurations, has gradually exhibited inadequate adaptability to meet the demands of the times. Field investigations have identified several predominant issues associated with current super high-rise developments: severe homogenization of architectural forms, inadequate functional mixtures, suboptimal activation of near-ground spaces, insufficient infrastructural planning in adjacent areas, and underutilization of potential urban landscapes. As China advances into an era of inventory regeneration, where urban renewal initiatives and improvements to spatial quality take precedence, these challenges emerge as pressing priorities that must be squarely addressed in contemporary urban development practices [4]. To sustainably boost urban vitality and systemic operational efficiency, cities need to implement comprehensive, long-term regeneration strategies through the adaptive reconfiguration of structural and functional layouts [5]. The revitalization of existing super high-rise buildings is critical for optimizing urban spatial arrangements, improving land-use efficiency, and advancing sustainable urban development. Accordingly, the assessment and upgrading of these structures have become a paramount priority for advancing high-quality urban environments.

Urbanity stands as an essential indicator for evaluating the health of urban societies. To underpin targeted, high-quality interventions in both ongoing and future urban regeneration processes, this study employs urbanity as the evaluative criterion for assessing the quality of existing super high-rise buildings. At present, urban regeneration has evolved into a central theme in urban discourse. Urbanity can be assessed not only through its physical manifestations but also by evaluating the performance levels of urban life it sustains. Adopting an urbanity-oriented perspective for urban regeneration endeavors confers distinct advantages [6]. Overall, as a critical metric for evaluating urban design and the quality of life of urban residents, urbanity embodies multi-dimensional urban characteristics, stimulates urban vitality, and promotes high-quality urban development. Thus, the application of urbanity as an evaluative framework for the revitalization of super high-rise buildings demonstrates inherent rationality as well as methodological superiority.

Urbanity serves as an open and transversal assessment mechanism that transcends the limitations inherent in traditional urban planning. It establishes a developmental paradigm that aligns with contemporary visions of urban society, facilitating the reconfiguration of cities to foster a sense of belonging while ensuring genuine habitability. Current research on the evaluation of architectural urbanity remains in its infancy—often referenced sporadically yet lacking systematic rigor. Existing studies employ incomplete indicator frameworks with minimal quantitative analysis and fail to validate actor-networks through empirical case integration.

This paper examines the factors influencing the urbanity of super high-rise buildings, selecting 21 representative indicators based on a literature review and field investigations. It identifies key factors involved in renovation and upgrading processes. A comprehensive evaluation and analysis of urbanity metrics can effectively illuminate the developmental status, latent potential, and existing challenges within urban architecture. This approach provides substantiated evidence for informed decision-making in urban planning, governance, and policy formulation.

2. Literature Review

2.1. Definition of Super High-Rise Buildings

The emergence and development of modern super high-rise buildings have been driven by multiple interrelated factors, including commercial demands, technological advancements, and humanity’s pursuit of vertical height. In a broad sense, super high-rise buildings mainly refer to structures whose height exerts a profound impact on their layout, design, and functionality, or those whose height creates distinctive conditions for construction and operation compared with buildings prevalent in a specific region and period. A key criterion for defining a super high-rise building lies in whether its design process is substantially influenced by the factor of tallness.

Specifically, this study defines buildings exceeding 100 m in height as super high-rise buildings, based on the following four considerations. First, the International Conference on High-Rise Buildings held in Pennsylvania in 1972 defined super high-rise buildings as those with more than 40 floors or a height exceeding 100 m. Second, Japan’s Building Standards Act [7] stipulates that buildings over 100 m in height are subject to mandatory inspections and evaluations of structural safety performance and environmental impacts; thus, 100 m has become a general threshold for classifying super high-rise buildings in the country. Third, according to China’s national standards, the Unified Standard for Design of Civil Buildings (GB 50352-2019) [8] and the Technical Specification for Concrete Structures of High-Rise Buildings (JGJ 3-2010) [9], buildings exceeding 100 m are categorized as super high-rise buildings. Fourth, the Code for Fire Protection Design of Buildings specifies that public buildings exceeding 100 m must be equipped with refuge floors (or rooms) and adopt fire prevention measures of a higher standard. Collectively, these regulatory and professional standards identify the 100 m mark as a critical threshold for distinguishing super high-rise buildings from ordinary high-rise constructions.

2.2. Evolution of Urbanity Theories

The urbanity level of a city is shaped by the combined effects of a multitude of factors. Given the diverse array of elements that underpin urbanity, only a multidimensional analytical framework can fully capture the complexity and richness inherent in this concept. In the 1930s, Louis Wirth first proposed the concept of urbanity, emphasizing the inherent diversity of urban life [10]. Many subsequent researchers have been influenced by his work. Some scholars conceptualize urbanity as a social construct that interacts deeply with physical space, arguing that it contributes significantly to urban vitality [11,12,13]; others contend that authentic urbanity can only be realized by accommodating diverse populations and their multifaceted behavioral demands within urban contexts [14,15]. Within the framework of urban systems theory, urbanity can be defined as an indicator reflecting the specific organizational state of social objects in a given urban context [16]. Urbanity is not only the outcome of the operation of urban organizations but also the operator that governs their formation and functioning. Essentially, urbanity encapsulates the interactive coupling between density and diversity among observable social entities within specific spatial settings.

While Chinese scholars embarked on research into this topic at a relatively later stage, they have nonetheless achieved a comprehensive and unambiguous grasp of all the pivotal theoretical tenets underpinning the concept of urbanity. A systematic synthesis of these investigations is necessary to formulate a sufficiently holistic understanding of urbanity theory. Urbanity encompasses two conceptual dimensions: On one hand, it represents a universal sense of urbanity which pertains to the interaction between urban space and individual citizens. This is primarily manifested through factors such as large population size, strong population aggregation, active economic behavior, diverse social composition, high-frequency elemental fluidity, elevated spiritual living standards, and accelerated material-spatial transformation [17,18,19,20]. On the other hand, it reflects a relatively high level of urbanity elements characterized by refined attributes, including autonomous economic agency, recreation-focused leisure lifestyles, leadership in cultural production, and emancipated civic consciousness [21,22,23]. The two aspects are complementary and mutually reinforcing, jointly constituting the full connotative characteristics of urbanity.

2.3. The Urbanity of Super High-Rise Buildings

From the architectural perspective, urbanity primarily emphasizes the capacity of architectural elements, such as functions and spatial configurations, to shape the characteristics of the external urban public space and foster urban activities [1,24]. Urbanity denotes the attribute that facilitates interaction between architecture and the urban context. The Urban Catalyst Theory, proposed by American architects Wayne Attoe and Donn Logan, posits that buildings endowed with urbanity can act as catalysts for urban development: they effectively elevate the comprehensive value and vitality of a city or district while guiding and consolidating the continuity of the urban context.

Super high-rise buildings play a pivotal role in urban contexts and constitute the largest component of the urban physical fabric; therefore, investigating the urbanity of super high-rise buildings holds considerable significance. The urbanity of super high-rise buildings manifests through dialectical dimensions of exteriority and interiority. “Exterior urbanity” operates through architectural recomposition aimed at enhancing the urban spatial structure while engaging with the surrounding environment to achieve symbiotic complementarity. Conversely, “interior urbanity” focuses on diversity and complexity within its own system operation that mirrors that of the city itself [25].

Previous fragmented studies have indicated that the development of evaluation systems for architectural urbanity has long lacked substantive progress: existing evaluation frameworks are commonly plagued by a limited number of indicators, making it difficult to comprehensively encompass the key factors influencing the degree of urbanity in high-rise buildings. Moreover, a precise quantitative analysis framework has yet to be established, resulting in assessments of architectural urbanity that largely remain at the level of superficial description and exhibit limited explanatory power. In light of this, the present study aims to construct a comprehensive evaluation system tailored to super high-rise buildings, systematically elucidate the mechanisms through which multiple factors affect their urbanity, and thereby provide a scientific decision-making basis for the retrofit and renewal of existing super high-rise buildings.

3. Case Area

3.1. Shanghai as the Case Study Area

China has ascended to a prominent global position, ranking among nations with the most extensive overall scale, highest density, and broadest influence of super-tall building clusters. As one of the earliest cities in China to embrace globalization, Shanghai has consistently maintained a pioneering role—both nationally and internationally—in designing and constructing super high-rise buildings. The development process of super high-rise buildings in Shanghai reflects the development and changes in the entire urban spatial pattern of Shanghai, as evidenced by the construction of Hongqiao Economic Development Zone (1983–1990), followed by the development of Lujiazui in Pudong (1990–1999), and then by the mid-to-late 1990s’ expansion of urban growth toward central districts, including People’s Square, Nanjing West Road, Xujiahui Commercial Hub, Nanjing East Road Pedestrian Street, and Yuyuan Commercial Area. The regionalized and centralized distribution pattern of super high-rise buildings has not only redefined Shanghai’s urban skyline but also continuously reshaped the city’s spatial morphology, serving as a visible manifestation of its economic ascendance. Therefore, an investigation into Shanghai’s super-tall buildings offers substantial exemplary value for the sustainable development of megacities across the globe.

3.2. Summary of the Problem of the Lack of Urbanity in Shanghai’s Super High-Rise Buildings

With the advancement of modern times and the rapid evolution of urban construction technologies and design concepts, the limitations in lifespan and inherent design constraints of early-built “legacy” structures have become increasingly evident. The urban core, now densely populated with super high-rise buildings, may outwardly project an image of “prosperity and vibrancy,” yet it progressively reveals a growing lack of adaptability to contemporary needs. Concurrently, the spatial experience and sense of place within these environments are gradually becoming homogenized, monotonous, and devoid of vitality. From the perspective of urban architectural identity, super high-rise buildings present several key challenges.

3.2.1. Homogeneous and Monotonous Architectural Morphology

The building facade serves as a direct reflection of its architectural image and form. Historically, primary methods employed in treating super high-rise building facades included paint, cladding tiles, mosaics, natural stone, aluminum alloy, and glass curtain walls. However, after prolonged exposure to environmental factors such as sunlight and weathering, many of these facades now exhibit signs of aging and deterioration. Given the dynamic evolution of urban environments, alongside the limitations imposed by prevailing design technologies and conceptual frameworks at their time of construction, numerous architectural projects that once defined trends decades ago now reveal significant shortcomings when evaluated from a contemporary standpoint. These include issues such as formal homogenization and morphological monotony. This phenomenon results in visual clutter, diminished hierarchy among design elements, and reduced capacity for the facade to effectively convey its intended architectural message. Furthermore, certain structures exhibit poor scale proportionality, where architectural forms appear as superficial symbolic attachments to the facade rather than as integrated three-dimensional spatial entities, thereby compromising their spatial presence (see Table 1).

Table 1. Summary of the building form issues of existing super high-rise buildings in Shanghai.

Existing Problems	Representative Cases	Problem Description
Architectural style incoherence		The facades and textural structures of super high-rise buildings differ substantially from those of surrounding structures, exhibiting stylistic opposition that hinders harmonization and consequently results in urban visual disorder.
Aged and outdated facade		Super high-rise buildings constructed in earlier decades exhibit surface contamination (including soiling and water staining) due to prolonged exposure to environmental elements. Additionally, various facade pathologies have been observed, comprising cracking, delamination, and metallic corrosion.
Complex building massing		Excessive and overly complex volumetric segmentation in super high-rise buildings often results in a lack of morphological coherence, while their substantial land occupancy negatively impacts the quality of near-ground spatial environments.
Imbalanced architectural scale		Taking the Shanghai Stock Exchange Building as a case study (120 m × 109 m), its facade employs grid and truss-style mesh decorations with relatively oversized proportions, which consequently diminishes the perceptual legibility of its actual volumetric scale.
Extreme architectural homogeneity		Driven by capital and economic interests, the fundamental imperative to shape space has led to the homogenization of architecture; meanwhile, architecture bears the responsibility of safeguarding urban cultural continuity, as excessive homogenization risks creating a monotonous ‘thousand cities with one face’ phenomenon.

3.2.2. Lack of Functional Diversity in Building

A more pervasive issue is the failure to adequately consider the broader impact on urban spatial landscapes. Many buildings present a disorganized visual appearance and demonstrate a lack of contextual sensitivity in their formal expression, exhibiting significant tendencies toward commercialization and aesthetic vulgarization. Additionally, they often neglect the inheritance of local cultural and architectural heritage, further weakening their connection to the urban context. In the early stages of Shanghai’s super high-rise building development, these structures were predominantly single-function developments primarily serving as office buildings, hotels, or commercial–office complexes. Their functional composition was relatively simplistic; most were designed exclusively for office use, while mixed-use configurations remained rare. This functional homogeneity contributed to a lack of coordination between buildings and diminished public engagement. It was not until the post-2000 period that a noticeable shift occurred, with an increasing number of super high-rise buildings adopting mixed-use designs—a trend reflecting evolving understandings of urban functionality and the role of high-rise buildings within integrated urban environments (see Table 2).

Table 2. Summary of the functional types of existing super high-rise buildings in Shanghai.

Number	Function Types	Representative Cases	Analytical Diagram
1	Office
2	Hotel
3	Retail–office
4	Mixed-use functions

3.2.3. Insufficient Vibrancy in the Near-Ground Space

The most visually striking and memorable aspect of super high-rise buildings for urban observers is often their iconic tower crowns, which dominate the city skyline. Conversely, the near-ground spaces—those intimately connected to the urban fabric—are frequently marginalized in both design considerations and public perception. These transitional zones between super high-rise buildings and their surrounding urban environments constitute the initial spatial experience encountered by building users, profoundly influencing both sensory perception and behavioral patterns. However, many urban super high-rise buildings exist as isolated “monuments,” detached from the surrounding city, resulting in near-ground spaces that fail to foster a human-scaled or continuous urban experience.

From a developer’s perspective, the design and construction of super high-rise buildings often prioritize unit-area profit maximization, frequently at the expense of broader urban spatial harmony and public accessibility. The pursuit of economic efficiency tends to overshadow considerations regarding the building’s relationship with its urban context. From a policy standpoint, current urban construction regulations in China remain inadequate. While quantitative standards such as building density, floor–area ratio (FAR), and green space ratio are well established, regulatory frameworks governing public spaces, urban environmental quality, and near-ground space design remain underdeveloped. Specifically, control indicators for elements within the public realm are incomplete; normative standards for near-ground space design have not been systematically implemented. This regulatory gap contributes to the often monotonous and formulaic quality of public spaces in super high-rise developments. From urban and architectural design perspectives, the near-ground space is a critical transitional interface—akin to urban street space—mediating between human-scaled environments and the monumental scale of super high-rise buildings. When this transitional space exhibits extreme scale disparities or abrupt spatial transitions, it disrupts the cohesive sense of place that characterizes well-integrated urban environments (see Table 3).

Table 3. Summary of problems in the near-ground space of existing super high-rise buildings in Shanghai.

Existing Problems	Representative Cases	Problem Description
Insufficient public space provision		Driven by the principle of maximizing benefits, most super high-rise buildings adopt a land-coverage-maximization strategy to achieve optimal floor–area ratio (FAR) utilization. Therefore, its near-ground space is typically ill-suited for human occupancy, and public open spaces that serve people for rest or buffering are generally lacking.
Lack of functional diversity		The deficit in functional diversity and programmatic integration disrupts the spatial and functional continuum between interior and exterior activities, thereby diminishing opportunities for spontaneous human engagement and participatory behavior.
		The spatial environment exhibits a monotonous character with a single function and form. This issue is particularly pronounced in near-ground space, resulting in an under-provision of externally accessible spaces that accommodate human-scale engagement. Consequently, the spatial vitality is markedly diminished.
Lack of dimensional harmony		The rear elevation of the Shanghai Center exhibits an excessively constrained space with adjacent buildings, inhibiting the formation of a continuous, high-quality near-ground space. This simultaneously compromises daylight penetration and natural ventilation performance, consequently degrading the overall spatial comfort.
		The near-ground space of the Shanghai Center employs a raised ground floor strategy to facilitate pedestrian circulation and traffic distribution. While this design accommodates the convergence and dispersion of movement flows, the excessive elevation—implemented to mitigate perceived spatial oppression—results in a loss of human-scaled proportionality.
Environmental disorganization		The unregulated management of near-ground space disrupts pedestrian circulation and encroaches upon existing roadways, green spaces, and public realms, thereby significantly compromising the establishment of high-quality near-ground spatial environments.
		The ground-floor commercial environment exhibits a deficient commercial ambiance, characterized by spatial disorder and inadequate management practices. This degraded condition not only compromises the architectural integrity and urban landscape coherence but also results in a profoundly diminished experiential quality of the near-ground space.
Lack of spatial continuity		The super high-rise buildings along urban arterials demonstrate attenuated physical and functional integration with adjacent urban fabrics. This spatial configuration engenders a fragmented and uncoordinated urban interface, concurrently intensifying vehicular traffic loads on the urban transportation network.
Insufficient greening		The massive volume of high-rise buildings typically results in inadequate greening provisions within their near-ground space, with the limited available spaces predominantly allocated to parking functions. When green spaces are introduced, they predominantly manifest as fragmented, punctiform vegetation elements that fail to establish environmental benefits. Furthermore, the hard ground constitutes a significant contributing factor to the urban heat island phenomenon.
Limited accessibility		The building facade employs visually impenetrable materials, resulting in compromised visual transparency. The entrance lacks differentiated design treatment, exhibiting a simplistic spatial hierarchy that diminishes its perceptual appeal.

3.2.4. Incomplete Infrastructure

Early super high-rise buildings exhibited limited consideration for the integration between internal circulation systems and urban transportation, often resulting in architecturally monotonous forms. The primary interface for urban traffic ingress typically occurred at the ground floor level, where complex traffic flows frequently reduced entrance spaces to mere functional conduits. Notably, ancillary spaces with potential for integrated transportation functions, such as basement levels and external plazas, were predominantly appropriated for private parking due to commercial imperatives. This allocation pattern systematically excluded public transportation considerations, consequently engendering inherent disorder and congestion within the building’s internal transport systems from their initial conception.

Furthermore, rooted in the historical context of their development, these buildings emerged under conventional land subdivision models that fostered architectural isolation and rigid property delineation. This legacy of fragmented development produced systemic deficiencies, including a lack of coordinated planning for surrounding public facilities and urban infrastructure, insufficient integration with broader urban spatial systems, discontinuous pedestrian networks, substandard infrastructure quality, and inadequate provisions for public rest and lingering. Such shortcomings collectively degraded the quality of urban public space and diminished opportunities for meaningful pedestrian engagement (see Table 4).

Table 4. Summary of problems of the infrastructure of existing super high-rise buildings in Shanghai.

Existing Problems	Representative Cases	Problem Description
Poor accessibility by transportation		The construction of Metro Line 2, which commenced prior to the development of the Shanghai International Finance Center (IFC), has led to a misaligned spatial relationship. In this scenario, the exit of the pedestrian passage directly faces the basement-level machine room of the IFC. Despite their close proximity, the absence of functional connectivity between these two urban infrastructure elements results in a suboptimal user experience and diminished operational convenience.
Weak walkability incentive		The inefficiency of pedestrian circulation systems generates significant inconvenience and exhibits poor connectivity with public transportation. The spatial disconnect between building interiors and adjacent street environments disrupts the traditional urban scale’s humanistic dimension and fractures the continuity of pedestrian networks, collectively contributing to a suboptimal pedestrian environmental quality.
Deficient recreational facilities		The near-ground spatial configuration features expansive plaza typologies, yet exhibits a disproportionate allocation of recreational amenities, thereby constraining opportunities for prolonged user engagement and social interaction.
Homogeneous guidance facilities		The guiding facilities within the venue demonstrate limited typological diversity, employ outdated design standards, and exhibit quantitative insufficiency. Furthermore, the deficient maintenance and management of ancillary facilities generate operational inefficiencies, thereby compromising user accessibility and convenience.

3.2.5. Underutilization of Urban Landscape Resources

Among Shanghai’s existing super high-rise buildings, urban landscape integration primarily manifests through rooftop gardens and observation decks. However, the case studies examined in this research predominantly originate from earlier construction periods. Constrained by the prevailing design paradigms, technical limitations, and inadequate consideration of embodied carbon in the construction industry of their time, these projects demonstrate limited implementation of urban “borrowed scenery” strategies—particularly rooftop gardens—with correspondingly modest landscape quality. Notably, the neglect of embodied carbon management in early practices not only intensified the environmental footprint of these structures but also constrained the long-term sustainability of rooftop garden systems.

(1)

Limited adoption of rooftop gardens: Rooftop gardens offer multifunctional benefits, including thermal insulation, environmental beautification, air purification, and microclimate regulation. Beyond these ecological contributions, they serve as compensatory green spaces that augment a building’s green footprint while enhancing the vertical dimension of urban landscapes. Nevertheless, during the early phases of high-rise development, rooftop garden implementation remained uncommon. When green rooftops were introduced, they typically manifested as rudimentary vegetation installations on existing structures, characterized by a lack of integrated architectural planning, minimal design coordination between horticultural elements and building form, insufficient embodied carbon awareness, and the absence of a systematic landscape strategy.

(2)

Suboptimal design quality of rooftop gardens: The design methodologies of early rooftop gardens were conventional and outdated, which compromised their comprehensive value and amplified lifecycle embodied carbon emissions. Common limitations included as follows:

• Eclectic element accumulation without coherent design principles.
• Adherence to traditional garden aesthetics has frequently conflicted with modern architectural styles, thereby compromising urban visual harmony.
• Maintenance challenges leading to neglect of environmental stewardship, unmanaged plant growth, limited plant diversity, and monotonous vegetation patterning.

These factors collectively resulted in simplified greening typologies, restricted botanical selection, and insufficient landscape articulation. Consequently, the resultant rooftop environments failed to achieve design excellence commensurate with their host buildings’ architectural significance, diminishing their potential to contribute meaningfully to Shanghai’s vertical green infrastructure.

4. Methodology

4.1. Analytic Hierarchy Process

The Analytic Hierarchy Process (AHP), developed by Saaty, is a structured decision-making methodology designed to handle complex and multifaceted problems [26]. The approach employs a hierarchical structure, with the primary decision goal positioned at the first level, followed by subsequent layers that systematically break down into evaluation criteria, sub-criteria, and alternative options [27]. AHP is particularly effective in situations where multiple interrelated and potentially conflicting criteria must be considered, as it facilitates the systematic prioritization of these criteria in relation to the overarching objective [28]. In this paper, AHP is integrated with expert interviews to assign weights to various impact elements of the urbanity of super high-rise buildings.

Through a comprehensive review of the literature, expert interviews, and empirical research on the urbanity of super high-rise buildings, this paper identifies and consolidates 21 evaluation indicators across five dimensions. Subsequently, the Delphi method was employed to engage 25 experts from various fields, including urban planning, architecture, government management, and real estate development (see Table 5). These experts were invited to complete a questionnaire aimed at determining the weights of the indicators within the evaluation framework. Experts made judgments from their respective professional perspectives to derive the evaluation matrix. The experts compared the five dimensions of the first-level indicator layer and constructed a judgment matrix for the first-level indicators. Similarly, the corresponding judgment matrix was constructed for the secondary indicators under each level 1 indicator. Table 6 presents the judgment matrix of the importance of the comparisons of the first-level indicators by expert 1.

Table 5. Statistics of experts’ basic information.

Characteristic		Number of People	Composition
Age (years)	Under 40	15	60%
	40–49	8	32%
	50–59	2	8%
Years of Experience	Under 10	10	40%
	10–19	9	36%
	20–29	6	24%
	≥30	0	0
Professional Title	Below Associate Senior	16	64%
	Associate Senior	4	16%
	Senior	5	20%
Educational Background	Bachelor’s	2	8%
	Master’s	14	56%
	Doctorate	9	36%

Table 6. Example of the judgment matrix of the two-by-two comparisons of level 1 indicators.

	Building Form	Building Function	Near-Ground Space	Transportation and Facilities	Urban Landscape
Building Form	1.0000	0.6007	0.8993	0.8993	1.7795
Building Function	1.6646	1.0000	2.1900	2.1900	4.1641
Near-Ground Space	1.1120	0.4566	1.0000	1.0000	4.1667
Transportation and Facilities	1.1120	0.4566	1.0000	1.0000	4.1667
Urban Landscape	0.5620	0.2401	0.2400	0.2400	1.0000

The outcome of the evaluation index matrix takes the form of a vector, and the product of the indicator weight vector is obtained via a normalization procedure. The detailed computational steps are outlined below:

First, process the matrix using a positive definite linear equation:

$$\overline{a_{ij}}=a_{ij}/{\displaystyle {\sum }_{k=1}^n{a}_{ij}(i,j=1,2,\cdots n)}$$

(1)

Second, sum the elements in the matrix:

$$\overline{w_i}={\displaystyle {\sum }_{j=1}^n{a}_{ij}(i,j=1,2,\cdots n)}$$

(2)

Third, normalize the matrix with respect to $\overline{w_i}$ in the aforementioned formula:

$$w_i=\overline{w_i}/{\displaystyle {\sum }_{i=1}^n\overline{w_i}(i=1,2,\cdots n)}$$

(3)

Fourth, calculate the maximum eigenvalue of the judgment matrix:

$${\lambda }_{\max }={\displaystyle \frac{1}{n}}{\displaystyle \sum _{i=1}^n\frac{{(Aw)}_i}{w_i}}$$

(4)

Given the complexity of objective phenomena in practical evaluations and the variability in cognitive levels across different groups, inconsistencies may arise in judgment outcomes. It is therefore a necessary step in the research process to conduct a consistency test on the judgment matrix to ensure its rationality and validity.

Calculate the maximum eigenvalue corresponding to the judgment matrix $\mathrm{\lambda }\max$; the high-precision consistency index (CI) is obtained via the power method. Here, CI denotes the consistency index, defined as

$$CI={\displaystyle \frac{{\lambda }_{\max }-n}{n-1}}$$

(5)

Meanwhile, the average random consistency index (RI) is introduced to eliminate the influence of matrix order on the CI value obtained by the power method. The consistency ratio (CR) is defined as CR = CI/RI, where the RI values corresponding to different matrix orders are shown in Table 7, with n representing the order of the matrix. The corresponding RI value can be determined based on the matrix order n, and thus the CR value can be calculated:

Table 7. The average random consistency index.

Index	1	2	3	4	5	6	7	8	9	10	11
RI	0	0	0.52	0.89	1.12	1.26	1.36	1.41	1.46	1.49	1.51

If CR < 0.10, the judgment matrix is considered to have acceptable consistency;

If CR ≥ 0.10, the judgment matrix must be revised until the consistency criterion is satisfied, after which the indicator weight calculation can proceed.

Through the aforementioned method, the weights of each indicator can be derived (see Table 8). A consistency test was then conducted; calculations revealed that all consistency ratios for both tiers were below 0.10. This indicates a satisfactory level of consistency in the results obtained, suggesting that the allocation of weight coefficients is reasonable.

Table 8. Evaluation system and weight distribution of urbanity of super high-rise buildings.

Primary Level Indicators	Weights	Secondary Indicators	Weights	Combined Weights
B1. Building Form [1,29,30,31]	0.1711	C1. Building height	0.1653	0.0283
		C2. Building density	0.1160	0.0198
		C3. Coordination of building forms	0.1160	0.0198
		C4. Color richness of building facades	0.1160	0.0198
		C5. Public and private ownership of buildings	0.1821	0.0312
		C6. Building location	0.3048	0.0522
B2. Building Function [32,33,34]	0.3526	C7. Diversity of building functions	0.3302	0.1164
		C8. Synergy of building functions	0.2352	0.0829
		C9. Publicness of building functions	0.2766	0.0975
		C10. Accessibility of buildings	0.1581	0.0557
B3. Near-Ground Space [34,35,36,37,38]	0.2036	C11. Functional diversity of near-ground space	0.3691	0.0751
		C12. Rationality of near-ground spatial scale	0.1596	0.0325
		C13. Continuity of near-ground spatial interfaces	0.1030	0.0210
		C14. Environmental comfort of near-ground spaces	0.1842	0.0375
		C15. Accessibility of urban open spaces	0.1842	0.0375
B4. Transportation and Facilities [37,39]	0.2036	C16. Accessibility of public transportation	0.4032	0.0821
		C17. Security of public transportation	0.1023	0.0208
		C18. Rationality of public recreational facilities	0.2472	0.0503
		C19. Rationality of public guidance facilities	0.2472	0.0503
B5. Urban Landscape [40,41]	0.0692	C20. Visual coverage ratio	0.6476	0.0448
		C21. Landscape diversity	0.3524	0.0244

4.2. Fuzzy Comprehensive Evaluation Method

Fuzzy comprehensive evaluation is grounded in the membership degree theory of fuzzy mathematics. This approach serves as a method for converting qualitative assessments into quantitative evaluations. When assessing specific cases, the fuzzy comprehensive evaluation method is employed. Fuzzy comprehensive evaluation is particularly suitable for research subjects that are challenging to quantify due to a multitude of indicators and a complex system. The results of this evaluation approach are both clear and systematic [42]. Combining fuzzy comprehensive evaluation with the Analytic Hierarchy Process can lead to a more complete evaluation effect.

First, an evaluation index set is constructed. Among the existing super high-rise buildings in Chinese cities, the oldest one is no more than 40 years old. At that time, these super high-rise buildings represented the pinnacle of construction technology, and currently, their structural safety remains relatively high. Furthermore, the cost associated with super high-rise buildings is substantial. In practical renovation scenarios, instances requiring demolition and reconstruction are virtually nonexistent. Therefore, considering the aforementioned circumstances, urban evaluation results for super high-rise buildings are categorized as poor, fair, or good. The renovation of buildings receiving a poor evaluation is deemed most urgent; thus, significant improvements and enhancements are recommended. For those with an average evaluation result, the urgency for renovation is comparatively low; minor updates for improvement are suggested. From this, the evaluation index set is determined as U = {${\mathrm{U}}_1$, ${\mathrm{U}}_2$, ${\mathrm{U}}_3$} = {poor, fair, better}.

Secondly, we determine the membership degree matrix for each specific indicator. Based on three-level evaluation criteria (see Table 9), 21 indicators from this case study are measured and scored to derive the membership degree matrix for each evaluation indicator, that is

$${\mathrm{B}}_{\mathrm{ij}}=\left[{\mathrm{b}}_{\mathrm{ij}1}, {\mathrm{b}}_{\mathrm{ij}2}, {\mathrm{b}}_{\mathrm{ij}3}\right]$$

(6)

Table 9. Measurement and grading of urbanity indicators for super high-rise buildings.

	Measurement Indicators and Methodology	Hierarchy
		Class I	Class II	Class III
Building height	Skyline primacy index = 1 − skyline datum plane height/building height	>0.65	0.45–0.65	<0.45
Building density	Green coverage ratio = green area/land area	<0.25	0.25–0.35	0.35–0.5
Coordination of building forms	$\mathrm{\sigma }=\sqrt{{\displaystyle \frac{1}{\mathrm{n}}}{{\displaystyle \sum }}_{\mathrm{i}=1}^{\mathrm{n}}{\left({\mathrm{a}}_{\mathrm{i}}-\mathrm{\mu }\right)}^2}$	>0.5	0.2–0.5	<0.2
	$\mathrm{T}=1-{\displaystyle \sum }_{\mathrm{i}=1}^{\mathrm{S}}{\mathrm{p}}_{\mathrm{i}}^2$	>0.5	0.2–0.5	<0.2
Color richness of building facades	$\mathrm{CPI}={\displaystyle \frac{1}{\mathrm{n}}}{\displaystyle \sum }_{\mathrm{i}=1}^{\mathrm{n}}{\mathrm{A}}^{\mathrm{i}}$	<5	5–7.6	7.6–10
	$\mathrm{the} \mathrm{CRI}=1-{\displaystyle \sum }_{\mathrm{i}=1}^{\mathrm{S}}{\mathrm{p}}_{\mathrm{i}}^2$	<0.2	0.2–0.5	0.5–0.8
Public and private ownership of buildings	1. Private property rights are managed by private individuals. 2. Mixed public and private property rights or public property rights but managed by private individuals. 3. Public property rights are managed by public organizations.	Conformity 1	Conformity 2	Conformity 3
Building location	1. Suburban business districts. 2. Urban sub-business districts or specialized business districts. 3. Urban core business districts.	Conformity 1	Conformity 2	Conformity 3
Diversity of building functions	Function types.	single function	2 functions	3 or more
Synergy of building functions	Types of non-profit functions.	0 non-profit function	1 non-profit function	2 or more
Publicness of building functions	Types of public functions.	0 public function	1 public function	2 or more
Accessibility of buildings	1. Sight visible through design. 2. Sight visible through materials. 3. Number of access points on the ground floor.	Conditions 1 and 2 are not met; 1 access point	Condition 1 or 2 is met; 2–3 access points	Conditions 1 and 2 are met; 4 or more
Functional diversity of near-ground space	Function types of near-ground space.	single function	2 functions	3 or more
Rationality of near-ground spatial scale	Building setback distance (L); setback distance/height (D/H).	D/H < 0.2 or D/H > 1	L > 25 m, 0.4 > D/H > 0.2 or 0.8 > D/H > 1	L > 25 m and 0.4 > D/H > 0.8
Continuity of near-ground spatial interfaces	$\mathrm{N}={\displaystyle \frac{{{\displaystyle \sum }}_{\mathrm{i}=1}^{\mathrm{n}}{\mathrm{K}}_{\mathrm{i}}}{\mathrm{L}}}$	<50%	50–70%	>70%
Environmental comfort of near-ground spaces	VGI = area of green plants in view/area of view × 100%	<15%	15–30%	>30%
Accessibility of urban open spaces	Within walking distance.	>750 m	400–750 m	<400 m
Accessibility of public transportation	Number of rail lines.	≤1	2	≥3
Security of public transportation	${\mathrm{VII}}_{\mathrm{n}}={\displaystyle \frac{{\mathrm{C}}_{\mathrm{n}}}{{\mathrm{R}}_{\mathrm{n}}}}\times 100\%$	>30%	15–30%	<15%
Rationality of public recreational facilities	Hundred-meter of recreational facilities density = (length of seating/site area) × $100$	<10 m/100 m	10–19 m/100 m	>19 m/100 m
Rationality of public guidance facilities	Hundred-meter of marker density = (number of markers/site area) × 100	<1/100 m	1–2/100 m	>2/100 m
Visual coverage ratio	Visual coverage ratio.	<20%	20–40%	>40%
Landscape diversity	Number of significant observable landscapes.	0 or 1	2	3 or more

As illustrated in the formula above, ${\mathrm{B}}_{\mathrm{ij}}$ represents the membership degree of the j-th secondary indicator within the i-th primary indicator. The comment set of ${\mathrm{B}}_{\mathrm{ij}}$ consists of three elements: ${\mathrm{b}}_{\mathrm{ij}1}$, ${\mathrm{b}}_{\mathrm{ij}2}$, and ${\mathrm{b}}_{\mathrm{ij}3}$, which, respectively, represent the evaluation of the membership degree of the indicator ${\mathrm{B}}_{\mathrm{ij}}$, representing evaluations corresponding to poor, fair, and good, regarding each indicator’s membership degree. The fuzzy relationship matrix for secondary indicators is obtained by integrating their respective membership degree matrices. Taking “urban landscape” as an example among first-level indicators, which has two corresponding second-level indicators. The fuzzy matrix can be expressed as follows:

$${\mathrm{R}}_{\mathrm{ij}}=\left[\begin{array}{c}{\mathrm{b}}_{\mathrm{ij}1}\\ {\mathrm{b}}_{\mathrm{ij}2}\end{array}\right]=\left[\begin{array}{ccc}{\mathrm{b}}_{\mathrm{ij}11}& {\mathrm{b}}_{\mathrm{ij}12}& {\mathrm{b}}_{\mathrm{ij}13}\\ {\mathrm{b}}_{\mathrm{ij}21}& {\mathrm{b}}_{\mathrm{ij}22}& {\mathrm{b}}_{\mathrm{ij}23}\end{array}\right]$$

(7)

Similarly, a fuzzy relation matrix can also be derived for first-level indicators. Then, the weighted average method is adopted to calculate the membership degree matrix of the evaluation object. The final result is determined by the magnitude of the values in the matrix [43].

5. Results—Case Study

5.1. Characteristics of Super High-Rise Buildings Prone to Renovation

Shanghai’s super high-rise structures serve as a critical reference model for megacity development worldwide. In parallel, as Shanghai transitions into a phase of urban development dominated by existing stock space, an increasing number of super-tall buildings are undergoing renovation and renewal. This trend reflects a strategic revitalization that redefines these structures’ functional and aesthetic value. Market data from real estate transactions, coupled with analyses from leading consulting firms such as Cushman & Wakefield (DTZ) and Jones Lang LaSalle (JLL), alongside reports from major bulk trading platforms, confirm a marked surge in engineering practices focused on retrofitting existing super-tall buildings within core urban districts. This upsurge aligns with escalating land prices in recent years.

The Special Plan for Shanghai Commercial Space Layout (2022–2035), officially released by the Shanghai Municipal Planning and Natural Resources Bureau in December 2022, delineates the spatial distribution of international-level and municipal-level commercial centers. A comparative analysis between this strategic planning framework and the spatial distribution of retrofitted 20 representative cases reveals a significant correlation (see Figure 1). The findings suggest that super high-rise buildings are most likely to undergo retrofitting under two key conditions:

Figure 1. The case of super high-rise building renovation coincides with the commercial space layout plan (the base map is from the “Shanghai Special Plan for Commercial Space Layout (2022–2035)” released in December 2022).

(1)

Strategic urban location: Buildings situated within central activity zones or formally designated international/municipal commercial hubs, as defined by the plan, exhibit higher retrofitting probabilities.

(2)

Building age and obsolescence: A substantial proportion of retrofit candidates are age-sensitive structures (typically ≥10 years old), whose functional obsolescence or outdated design presents clear opportunities for adaptive reuse and revitalization.

Drawing on the principles elaborated above, this study selected 20 representative cases of renovated super high-rise buildings. A comparative assessment of urbanity was then conducted to evaluate the performance of these buildings in both pre-intervention and post-intervention states (see Figure 2 and Table 10).

Figure 2. Twenty representative cases of bulk transactions and renovation of some stock of super high-rise buildings in Shanghai in recent years.

Table 10. The construction years of the 20 representative cases.

Original Build Era	Number of Projects	Representative Case
1978–1989	1	East China Electric Power Building (1989)
1990–1999	13	Shanghai JC Mandarin Hotel (1990), Shanghai Galaxy Hotel (1990), Central Plaza (1998), World Trade Center (1996), Shui On Plaza (1997), Golden Bell Plaza (1997), Amigo Mansion (1997), Jing’an Gaohe Mansion (1998), Shanghai Plaza (1998), China Resources Times Plaza (1998), Lippo Plaza (1998), Shanghai Central Plaza (1999), Shanghai International Shipping Finance Tower (1999)
2000–2009	6	Citic Square (2000), Pudong Development Building (2000), K11 Mall (2004), Grand Gateway Plaza (2005), Shanghai Shimao Plaza (2006), Shanghai Shengbang International Building (2009)

5.2. Data Processing and Case Evaluation

5.2.1. Pre- and Post-Intervention Assessment of Urbanity

In accordance with the three-tiered evaluation criteria outlined in Table 9, a comprehensive assessment was conducted to measure and score 21 indicators across 20 case studies. Subsequently, the weighted average method was employed to calculate the affiliation matrix of the evaluation object, with the final result determined by the magnitude of the values within this matrix.

The calculation process is illustrated using the Shanghai JC Mandarin Hotel (1990, 122 m) as an example. It follows a consistent methodology applied to all other cases. Initially, we measured and scored the 21 indicators during both pre- and post-renovation phases of the Shanghai JC Mandarin Hotel and calculated each indicator’s membership degree matrix (see Table 11).

Table 11. The 21 urbanity indicators evaluation of the Shanghai JC Mandarin Hotel.

Indicator	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21
Degree (pre)	III	II	II	I	I	II	I	I	I	II	II	I	II	II	III	III	III	I	II	I	II
Degree (post)	III	III	III	II	I	III	III	I	III	II	II	II	I	II	III	III	III	I	III	II	II

The fuzzy matrix of ${\mathrm{B}}_1$ of the pre-renovation phase can be expressed as

$${\mathrm{R}}_{11}=\left[\begin{array}{ccc}0& 0& 1\\ 0& 1& 0\\ 0& 1& 0\\ 1& 0& 0\\ 1& 0& 0\\ 0& 1& 0\end{array}\right]$$

The weights corresponding to the indicator ${\mathrm{B}}_1$ are ${ \mathrm{W}}_{11}$= [0.1653, 0.116, 0.116, 0.116, 0.1821, 0.3048]. The evaluation vector of ${\mathrm{B}}_1$ can be obtained as

$$\begin{array}{c}{\mathrm{B}}_{1 }={ \mathrm{W}}_{11}\circ {\mathrm{R}}_{11}=\left[0.1653, 0.116, 0.116, 0.116, 0.1821, 0.3048\right]\circ \left[\begin{array}{ccc}0& 0& 1\\ 0& 1& 0\\ 0& 1& 0\\ 1& 0& 0\\ 1& 0& 0\\ 0& 1& 0\end{array}\right]\\ =\left[0.2981, 0.5368, 0.1653\right]\hfill \end{array}$$

Similarly, the evaluation vectors of ${\mathrm{B}}_2$, ${\mathrm{B}}_3$, ${\mathrm{B}}_4$, and ${\mathrm{B}}_{5 }$ can be obtained: ${\mathrm{B}}_2$ = [0.8420, 0.1581, 0.0000], ${\mathrm{B}}_3$ = [0.1596, 0.6563, 0.1842], ${\mathrm{B}}_4$ = [0.2472, 0.2472, 0.5055], and ${\mathrm{B}}_5$ = [0.6476, 0.3524, 0.0000]. The overall vector B is

$$\begin{array}{c}\mathrm{B} =\left[0.1711, 0.3526, 0.2036, 0.2036, 0.0692\right]\circ \left[\begin{array}{ccc}0.2981& 0.5368& 0.1653\\ 0.8420& 0.1581& 0.0000\\ 0.1596& 0.6563& 0.1842\\ 0.2472& 0.2472& 0.5055\\ 0.6476& 0.3524& 0.0000\end{array}\right]\\ =\left[0.4756, 0.3560, 0.1687\right]\hfill \end{array}$$

The urbanity of the Shanghai JC Mandarin Hotel prior to its renovation was quantitatively assessed through the magnitude of values in the matrix, resulting in an evaluation vector of [0.4756, 0.3560, 0.1687]. According to the established evaluation criteria, this outcome corresponds to Grade “I”, categorizing the pre-renovation urbanity as “poor”. Subsequently, the post-renovation urbanity of the Shanghai JC Mandarin Hotel was evaluated using the same methodology and yielded the evaluation vector of [0.3426, 0.2469, 0.4108]. This result falls under Grade “III”, categorizing the post-renovation urbanity as “good”. This demonstrated a statistically significant improvement in the hotel’s urbanity after the renovation. The evaluation of 21 indicators and the calculation of membership degrees for 20 cases before and after renovation are presented in Figure 3 and Table 12.

Figure 3. Visualization of the results of the evaluation of the urbanity of 20 cases.

Table 12. Calculation results of membership degrees before and after renovation of 20 cases.

Case Name		Degree of Membership			Maximum Membership Degree Level
		b1	b2	b3
1. East China Electric Power Building	Degree (pre)	0.5811	0.3000	0.1193	I
	Degree (post)	0.3907	0.4292	0.1804	II
2. Shanghai JC Mandarin Hotel	Degree (pre)	0.4756	0.3560	0.1687	I
	Degree (post)	0.3426	0.2469	0.4108	III
3. Shanghai Galaxy Hotel	Degree (pre)	0.3982	0.3358	0.2662	I
	Degree (post)	0.3907	0.4292	0.1804	II
4. Central Plaza	Degree (pre)	0.5505	0.2666	0.1832	I
	Degree (post)	0.2619	0.5126	0.2258	II
5. World Trade Center	Degree (pre)	0.5811	0.3000	0.1193	I
	Degree (post)	0.2619	0.5126	0.2258	II
6. Shui On Plaza	Degree (pre)	0.4181	0.2994	0.2828	I
	Degree (post)	0.1013	0.2223	0.6767	III
7. Golden Bell Plaza	Degree (pre)	0.3671	0.3429	0.2903	I
	Degree (post)	0.2544	0.5464	0.1994	II
8. Amigo Mansion	Degree (pre)	0.4803	0.2994	0.2205	I
	Degree (post)	0.3869	0.5021	0.1112	II
9. Jing’an Gaohe Mansion	Degree (pre)	0.3671	0.3235	0.3097	I
	Degree (post)	0.3671	0.4056	0.2276	II
10. Shanghai Plaza	Degree (pre)	0.5811	0.3000	0.1193	I
	Degree (post)	0.1013	0.2223	0.6767	III
11. China Resources Times Plaza	Degree (pre)	0.5002	0.3368	0.1633	I
	Degree (post)	0.2888	0.2110	0.5004	III
12. Lippo Plaza	Degree (pre)	0.3671	0.3235	0.3097	I
	Degree (post)	0.3671	0.4056	0.2276	II
13. Shanghai Central Plaza	Degree (pre)	0.5811	0.3000	0.1193	I
	Degree (post)	0.3907	0.4292	0.1804	II
14. Shanghai International Shipping Finance Tower	Degree (pre)	0.4181	0.2994	0.2828	I
	Degree (post)	0.1013	0.2223	0.6767	III
15. Citic Square	Degree (pre)	0.5002	0.3368	0.1633	I
	Degree (post)	0.2888	0.2110	0.5004	III
16. Pudong Development Building	Degree (pre)	0.5811	0.3000	0.1193	I
	Degree (post)	0.3907	0.4292	0.1804	II
17. K11 Mall	Degree (pre)	0.4181	0.2994	0.2828	I
	Degree (post)	0.1013	0.2223	0.6767	III
18. Grand Gateway Plaza	Degree (pre)	0.4228	0.2871	0.2903	I
	Degree (post)	0.2544	0.5464	0.1994	II
19. Shanghai Shimao Plaza	Degree (pre)	0.5200	0.3248	0.1554	I
	Degree (post)	0.1978	0.3694	0.4330	III
20. Shanghai Shengbang International Building	Degree (pre)	0.4684	0.4002	0.1316	I
	Degree (post)	0.3671	0.4056	0.2276	II

5.2.2. Strategies for Urbanity Improvement of 20 Representative Cases

In the aforementioned study, a fuzzy comprehensive evaluation model was utilized to assess the urbanity of 20 representative cases. The findings indicated that the urbanity of these high-rise buildings was enhanced to varying degrees through the implementation of targeted retrofitting strategies. By systematically analyzing the retrofitting and renewal strategies employed across five dimensions of urbanity enhancement in these 20 cases, this study provides a foundation for developing specific strategies aimed at improving urbanity (see Table 13).

Table 13. Summary of strategies for enhancing urbanity of 20 cases.

Case Name	Building Form	Building Function	Near-Ground Space	Transportation and Facilities	Urban Landscape
1. East China Electric Power Building	◆ Optimize the facade texture (retain the main texture of the original façade)	◆ Building function replacement (office-to-hotel)	◆ Increase the functional mix ◆ Integrate with the urban space	◆ Increase leisure facilities ◆ Optimize guiding facilities	/
2. Shanghai JC Mandarin Hotel	◆ Optimize the volume ◆ Optimize the facade (solid wall–glass curtain wall)	◆ Building function replacement (hotel-to-office and retail)	◆ Increase the functional mix ◆ Reshape the ecological pattern	◆ Increase leisure facilities ◆ Optimize guiding facilities	◆ Increase roof greening ◆ Add a top viewing layer
3. Shanghai Galaxy Hotel	◆ Renovation of facade ◆ Basement renovation	◆ Building function replacement (hotel-to-office and retail)	◆ Reshape the ecological pattern ◆ Integrate with the urban space	◆ Increase leisure facilities ◆ Optimize guiding facilities	◆ Increase roof greening
4. Central Plaza	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space ◆ Reshape the ecological pattern	◆ Increase leisure facilities ◆ Optimize guiding facilities	/
5. World Trade Center	◆ Optimize the facade	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space ◆ Reshape the ecological pattern	◆ Reorganize the transportation at the base ◆ Optimize guiding facilities	◆ Increase roof greening ◆ Add a top viewing layer
6. Shui On Plaza	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space	◆ Integration of transportation ◆ Optimize guiding facilities	◆ Add top viewing layers
7. Golden Bell Plaza	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Coupled urban space	◆ Increase leisure facilities ◆ Optimize guiding facilities	/
8. Amigo Mansion	◆ Renovation of facade	◆ Increase business formats	◆ Increase the functional mix	◆ Optimize guiding facilities	/
9. Jing’an Gaohe Mansion	◆ Optimize the facade texture	◆ Optimize the function	◆ Coupled urban space	◆ Increase leisure facilities ◆ Optimize guiding facilities	/
10. Shanghai Plaza	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space ◆ Reshape the ecological pattern	◆ Integration of transportation ◆ Optimize guiding facilities	/
11. China Resources Times Plaza	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space ◆ Reshape the ecological pattern	◆ Integration of transportation ◆ Increase leisure facilities ◆ Optimize guiding facilities	◆ Add top viewing layers
12. Lippo Plaza	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats	◆ Coupled urban space	◆ Integration of transportation ◆ Optimize guiding facilities	/
13. Shanghai Central Plaza	◆ Optimize the facade	◆ Increase business formats	◆ Increase the functional mix ◆ Reshape the ecological pattern	◆ Integration of transportation ◆ Optimize guiding facilities	/
14. Shanghai International Shipping Finance Tower	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space	◆ Integration of transportation ◆ Optimize guiding facilities	◆ Add top viewing layers
15. Citic Square	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space	◆ Integration of transportation ◆ Increase leisure facilities ◆ Optimize guiding facilities	◆ Increase roof greening
16. Pudong Development Building	◆ Renovation of facade	◆ Increase business formats	◆ Integrate with the urban space	◆ Increase leisure facilities ◆ Optimize guiding facilities	◆ Add a top viewing layer
17. K11 Mall	◆ Optimize the facade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space ◆ Reshape the ecological pattern	◆ Integration of transportation ◆ Increase leisure facilities ◆ Optimize guiding facilities	◆ Add top viewing layers
18. Grand Gateway Plaza	◆ Optimize the façade (solid wall–glass curtain wall)	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space	◆ Integration of transportation ◆ Increase leisure facilities ◆ Optimize guiding facilities	◆ Increase roof greening
19. Shanghai Shimao Plaza	◆ Renovation of facade	◆ Increase business formats ◆ open floor space	◆ Increase the functional mix ◆ Integrate with the urban space	◆ Integration of transportation ◆ Optimize guiding facilities	/
20. Shanghai Shengbang International Building	◆ Renovation of facade	◆ Increase business formats	◆ Increase the functional mix ◆ Reshape the ecological pattern	/	/

5.3. Strategies to Enhance the Urbanity of Existing Super High-Rise Buildings

Based on the AHP-derived weight distribution and FCEM evaluation results, this section proposes targeted urbanity enhancement strategies for existing super high-rise buildings. The weight analysis reveals that building function (B2) has the highest weight (0.3526), followed by near-ground space (B3, 0.2145), transportation and facilities (B4, 0.2145), building form (B1, 0.1711), and urban landscape (B5, 0.0473) (see Figure 4). This weight hierarchy indicates that functional optimization should be the core of urbanity enhancement, while near-ground space improvement and infrastructure integration are equally critical supporting dimensions. The following strategies are formulated by integrating the weight significance and case study findings.

Figure 4. Weights of indicators for evaluating the urbanity of super high-rise buildings.

5.3.1. Building Form Optimization: Contextual Coordination and Character Shaping

Building form accounts for 0.1711 of the total weight, with building location (C6, combined weight 0.0522) and public–private ownership (C5, 0.0312) as the top two secondary indicators. This suggests that the spatial location adaptability and public accessibility of building form are more important than physical attributes such as height and density.

First, contextual coordination of architectural form. For buildings with stylistic incoherence (e.g., the Lucky Mansion and the Universal Mansion), facade renovation should adopt a “complementary integration” approach rather than blind modernization [30,44]. For example, the facade material can be partially updated to align with the surrounding historical context while retaining the original architectural skeleton, balancing cultural inheritance and visual harmony [45]. For buildings with aged facades (e.g., the Qilu Tower), green renovation technologies such as energy-saving glass replacement and vertical greening can be adopted to improve both aesthetic and environmental performance.

Second, rational control of building scale and proportion. Aiming at the imbalanced scale problem (e.g., the Shanghai Stock Exchange Building), local modification of facade decorations can be carried out to adjust the visual perception [31,46]. For instance, optimizing the proportion of grid decorations to enhance the legibility of the building volume. Meanwhile, for buildings with complex massing, volumetric simplification through partial demolition or external cladding renovation can be considered to improve morphological coherence and reduce the negative impact on near-ground space.

Third, strengthen public attribute expression. Based on the weight of public–private ownership (C5), buildings should appropriately open private spaces to the public [33]. For example, setting public art galleries or exhibition spaces on the ground floor of commercial super high-rise buildings and optimizing the transparency of building facades to enhance the interaction between internal and external spaces.

5.3.2. Building Function Upgrading: Diversification and Synergy Enhancement

As the most weighted primary indicator (0.3526), the building function’s secondary indicators show that functional diversity (C7, 0.1164), functional publicness (C9, 0.0975), and functional synergy (C8, 0.0829) are the key influencing factors. This confirms that single-function dominance is a core barrier to urbanity, and functional mixing and public accessibility are crucial for improvement. Across all building typologies, functional utility serves as the core impetus for public engagement. A functionally diverse yet systematically coordinated spatial configuration is instrumental in drawing substantial foot traffic, which in turn infuses the building with a distinct sense of urbanity.

First, promote mixed-use functional transformation. This strategy involves the strategic integration of diverse, contemporary functional elements to enhance both the functional capacity and environmental quality of existing super high-rise buildings [47]. Key interventions include activating ground-floor commercial spaces through the insertion of retail or service-oriented uses, as well as incorporating non-profit functions such as community centers, cultural spaces, or public amenities [33,34]. The approach aims to diversify building use types while improving spatial efficiency and user experience through targeted functional augmentation. These interventions address evolving urban functional demands while leveraging existing structural frameworks.

Second, enhance functional synergy and accessibility. For mixed-use buildings with poor functional coordination, optimize the internal circulation system to strengthen the connection between different functional areas [44,47]. For example, setting shared atriums and vertical transportation hubs to improve the flow efficiency between office, retail, and leisure spaces. Meanwhile, based on the weight of functional accessibility (C10, 0.0557), adjust the entrance design to ensure that public functions are easily accessible to pedestrians, avoiding the isolation of private and public spaces.

Third, expand public functional space. In response to the high weight of functional publicness (C9), increase the proportion of non-profit public spaces, such as urban libraries, community activity centers, and public roof gardens [33]. For example, the rooftop of the Jing An Kerry Center can be transformed into a public observation platform with landscape gardening, improving the public value of the building space.

5.3.3. Near-Ground Space Activation: Vitality Improvement and Humanistic Care

Near-ground space shares the same weight as transportation and facilities (0.2145), with key secondary indicators including spatial continuity (C12, 0.0485), greening provision (C16, 0.0452), and public space sufficiency (C11, 0.0429). This indicates that the continuity, ecological quality, and public availability of near-ground space are core to urbanity enhancement.

First, construct a continuous near-ground space. This strategy aims to enhance the synergistic integration of diverse land-use functions within near-ground spaces through three-dimensional functional configuration [44,48]. Key components include landscape greening (both ecological and aesthetic enhancement), cultural and artistic facilities (public enrichment), leisure and entertainment spaces (social vitality), and community service provisions (daily functionality). The approach seeks to achieve not only functional diversity but also spatial interweaving and functional connectivity—ensuring that these uses are organically intertwined through vertical and horizontal adjacencies, thereby fostering synergistic interactions [49].

Second, strengthen the ecological greening configuration. Aiming at insufficient greening, increase the proportion of green space in near-ground areas, adopting a combination of central green squares and scattered green patches [35]. Vertical greening and roof greening can be integrated to improve the ecological environment and mitigate the urban heat island effect. These interventions collectively amplify the ecological utility of super high-rise developments by expanding green coverage, improving air quality, and supporting urban biodiversity.

Third, optimize public space design. This strategy enhances public space accessibility and adaptability through strategic building setbacks (creating transitional buffer zones), plaza formation, and green space development (softening architectural massing), along with multi-functional open areas that accommodate diverse public activities as well as daily rest needs [31,48,49]. By modulating building boundaries, these measures foster spatial diversity that encourages pedestrian engagement, social interaction, and flexible use patterns while mitigating the visual dominance of super high-rise buildings.

5.3.4. Transportation and Facilities Integration: Accessibility Improvement and Service Optimization

Transportation and facilities, with equal weight to near-ground space, have key indicators including public transportation connection (C17, 0.0485) and recreational facility provision (C19, 0.0452). This highlights the importance of integrating building transportation systems with urban infrastructure and improving supporting service facilities.

First, strengthen the connection with public transportation. An efficient public transportation system is conducive to promoting the mixed use of urban land, thereby better aligning with the sustainable development goals of cities [35]. For buildings with poor public transportation accessibility (e.g., the Shanghai International Financial Center), construct underground pedestrian passages connecting to nearby metro stations to realize “seamless transfer”. Meanwhile, optimize the internal parking system, allocate a certain proportion of public parking spaces, and encourage the use of public transportation to reduce traffic congestion [50,51].

Second, improve pedestrian circulation efficiency. Aiming at weak walkability (e.g., the Longemont Shanghai), optimize the pedestrian flow line design, setting clear guidance signs and widening pedestrian paths [35,51]. For buildings with complex traffic flows, separate pedestrian and vehicular routes through elevated walkways or underground passages to improve walking safety and comfort [52].

Third, supplement and upgrade supporting facilities. For buildings with deficient recreational facilities (e.g., the Jing An Kerry Center), add outdoor fitness equipment, children’s play areas, and rest pavilions in the plaza space [52]. Update outdated guidance facilities (e.g., the Haitong Securities Building) to intelligent guidance systems, improving user convenience. Meanwhile, increase public rest facilities to extend pedestrian stay time and enhance space vitality [53].

5.3.5. Urban Landscape Enhancement: Resource Utilization and Quality Improvement

Although urban landscape has the lowest weight (0.0473), it still plays a supplementary role in urbanity enhancement and serves as a critical carrier for reducing embodied carbon in super high-rise building renewal. Reducing resource consumption, lowering carbon emissions, and minimizing waste generation can enhance building health performance and tenant utilization efficiency while simultaneously boosting the overall asset value of super high-rise buildings [54,55].

First, promote rooftop garden renovation and upgrading. For buildings with rudimentary rooftop greening, conduct systematic landscape design that prioritizes low-embodied-carbon materials (e.g., recycled composite materials for garden paths and local native plant species) to minimize carbon emissions from material production and transportation [41,56]. To achieve thermal comfort, optimize resource utilization efficiency, and reduce embodied carbon emissions, super high-rise buildings must adapt to vertical microclimate variations [57]. It is proposed to incorporate interval outdoor gardens at specific floor levels, which can function as ventilation corridors to enhance air circulation—reducing the energy consumption of mechanical ventilation systems and indirectly lowering operational carbon. Simultaneously, such interventions contribute to increasing urban green coverage and mitigating the urban heat island effect—aligning with the vertical landscape optimization strategy for urbanity enhancement.

Second, adopt “borrowed scenery” strategies and synergize energy utilization. Make full use of the high-altitude advantage of super high-rise buildings to integrate surrounding urban landscapes (e.g., rivers, parks, and historical buildings) into the architectural design, reducing the need for additional artificial landscape structures and thus cutting embodied carbon [58]. Meanwhile, combine rooftop gardens with renewable energy facilities (e.g., thin-film solar panels on non-green areas of the roof) to realize the integration of landscape, energy supply, and carbon reduction [31,59]. This synergy not only improves the utilization efficiency of rooftop space but also offsets the embodied carbon of renewable energy equipment through long-term operational carbon savings.

Third, strengthen landscape maintenance management. Establish a long-term maintenance mechanism for rooftop gardens and near-ground green spaces, ensuring the survival of plants and the normal operation of landscape facilities [60]. Regular pruning and updating of vegetation can maintain landscape diversity and freshness, avoiding the degradation of landscape quality due to neglect. Additionally, optimizing maintenance processes (e.g., using electric maintenance tools instead of fuel-powered ones) can further reduce the operational carbon associated with landscape management, complementing embodied carbon control.

6. Discussion

6.1. Theoretical Implications

This study constructs a comprehensive urbanity evaluation system for existing super high-rise buildings, integrating 21 indicators across five dimensions, which fills the gap in the existing literature’s lack of systematic quantitative evaluation frameworks for architectural urbanity. The AHP weight distribution clarifies the hierarchical relationship of influencing factors, confirming that building function is the core driver of urbanity, which enriches the theoretical understanding of the interaction mechanism between architectural attributes and urbanity.

Furthermore, the integration of AHP and FCEM realizes the quantitative assessment of urbanity, overcoming the limitations of traditional qualitative description. The evaluation results of Shanghai cases provide empirical support for the applicability of the evaluation system, laying a foundation for the standardization of urbanity assessment in super high-rise building renewal projects. This research also expands the application scope of urbanity theory in vertical urban space, providing a new theoretical perspective for stock urban renewal research.

6.2. Practical Implications

The proposed strategies are closely combined with the weight significance and case problems, ensuring strong operability. For urban planners and policymakers, the weight distribution can guide the allocation of renewal resources—prioritizing functional transformation and near-ground space improvement to maximize the efficiency of urbanity enhancement. For developers, the strategies provide specific renovation directions, such as mixed-use transformation and public space expansion, balancing economic benefits and social value.

The research findings also have reference significance for global megacities facing similar super high-rise building renewal challenges. Shanghai, as a representative city with a large number of super high-rise buildings, has experience in problem diagnosis and strategy formulation that can be adapted to other high-density cities, promoting the sustainable development of vertical urban space.

6.3. Limitations and Future Research Directions

This study has certain limitations. First, the case selection is limited to Shanghai, and the evaluation results and strategies may lack universality for cities with different development levels and cultural backgrounds. Future research can expand the case scope to include small and medium-sized cities or cities in different regions to optimize the evaluation system and strategies.

Second, weight determination relies on experts’ subjective judgments, which may have certain biases. Future research can combine objective data (e.g., pedestrian flow, space utilization rate) with expert evaluation to improve the accuracy of weight distribution. Third, this study does not conduct a follow-up evaluation of the strategy implementation effect. Future research can track the renovation projects to verify the effectiveness of the proposed strategies and form a closed-loop optimization mechanism.

In addition, with the development of intelligent urban construction, future research can integrate digital technologies such as BIM and big data into the urbanity evaluation and renovation design, realizing the intelligent and precise enhancement of super high-rise building urbanity.

7. Conclusions

The study takes existing super high-rise buildings in Shanghai as the research object, constructs an urbanity evaluation system based on AHP and FCEM, identifies the main problems of insufficient urbanity, and proposes targeted enhancement strategies by integrating indicator weight analysis. The key conclusions are as follows:

The weight distribution shows that building function (0.3526) is the most important factor affecting urbanity, followed by near-ground space and transportation and facilities (both 0.2145), indicating that functional optimization, near-ground space activation, and infrastructure integration are the core of urbanity enhancement. The FCEM evaluation results reveal that most existing super high-rise buildings in Shanghai have moderate urbanity, with problems such as functional singularity, near-ground space stagnation, and poor infrastructure integration.

Corresponding strategies are proposed for each dimension: building form optimization through contextual coordination and scale adjustment; building function upgrading via diversification and synergy enhancement; near-ground space activation by improving continuity and greening; infrastructure integration through public transportation connection and facility upgrading; and urban landscape enhancement by optimizing rooftop resources.

This research provides a scientific evaluation framework and practical strategies for the urbanity enhancement of existing super high-rise buildings, contributing to the high-quality renewal of stock urban space. It also provides a reference for global megacities to address similar challenges, promoting the construction of livable and resilient vertical urban environments.