Beijing Symbiotic Courtyard Model’s Post Evaluation from the Perspective of Stock Renewal

Abstract

Stock renewal is one of the important methods of urban renewal, which focuses on optimizing and reusing existing urban spaces. With the increasing land pressure in present-day China and the need for land to be reclassified, the thinking mode of stock updating has become increasingly important. Beijing symbiotic courtyard is a representative urban renewal model that combines the characteristics of traditional quadrangle dwelling and modern architecture, aiming to achieve the symbiosis of history and modernity. After several years of implementation, the effectiveness of this model has become a matter of concern for all parties involved. Therefore, this paper takes stock renewal as the observation perspective, describing an evaluation for the Beijing symbiotic courtyard model, which contains different types of residents living in particular historical districts. It attempts to propose corresponding strategies, aiming to provide a more comprehensive thinking angle and planning method for the sustainability of stock renewal. In contrast to earlier studies, the proposed methods involve a specific mathematical statistical model called the IPA-KANO model, in addition to other traditional urban renewal methods. For a wide range of problems including historical district evaluation and renewal, the approach leads to potentially less errors than caused by manual operation. This comes from the fact that all the data are collected through survey questionnaires and big data, so the technical restriction of using mathematical model is to some extent ruled out in this new approach. Moreover, the approach offers new potential problems that cannot be handled using earlier techniques. After the calculation, although there are still defects, local residents are generally satisfied with the Beijing symbiotic courtyard model. The result suggests that it is of importance to reference this model for urban renewal so that can be widely promoted in historical district vitality regeneration.

1. Introduction

Since the beginning of urban development, the quality of living conditions has always been a hot topic of close concern for people from all social classes. The residential environment to a large extent reflects the development level of a city [1]. Since the reform and opening up, China has been implementing the strategy of “incremental development.” This aggressive, unbounded development has somewhat alleviated urban housing difficulties but has also caused negative impacts, such as real estate chaos [2], the overdevelopment of cities [3], and the intensification of the urban–rural dual structure [4]. Therefore, controlling the scale of development and achieving sustainable development have become important topics for planners and even the nation [5].

In the 2021 government work report, China, for the first time, clearly proposed the implementation of the “urban renewal” initiative [6,7], indicating that China’s planning has shifted from simple, extensive quantitative development to quality-oriented development, with high-quality development becoming a consensus. For cities, the connotation of stock renewal is not limited to the rational use of space but is also about how to promote the transformation of urban development models. In the process of urban space renewal, it is necessary to balance multiple urbanization tasks, including improving the living environment, utilizing space efficiently, promoting low-carbon green development, and continuing historical contexts. Chinese research on urban stock renewal mainly focuses on renewal mechanisms [8], stock land assessment [9], and spatial utilization methods [10,11]. The research perspective has shifted from solely improving physical spaces such as old houses, traditional dwellings, and historical districts to optimizing functions, reshaping appearances, achieving green transformation, and enhancing vitality in key urban areas under a people-oriented approach.

The Beijing municipal government responded promptly by issuing the “Beijing Urban Renewal Regulations” at the end of 2022, which clearly stated that Beijing’s urban renewal follows the principle of “multi-stakeholder participation and joint construction and sharing” and adopts a strategy of “simultaneous retention, renovation, and demolition, with a focus on preservation, utilization, and enhancement.” This makes the initiatives proposed in Beijing’s 2019 government work report, such as promoting the organic renewal of courtyard houses in core areas through an application-based improvement and “Symbiotic courtyard” renovation, increasingly important.

The concept of “Symbiotic Courtyard” refers to combining the original mixed-use courtyards with modern functions under the premise of demolishing illegal constructions and restoring courtyard spaces [12]. While retaining the traditional spatial pattern of siheyuan (courtyard houses), it aims to improve residents’ living conditions, achieving architectural, residential, and cultural symbiosis. The renovation model of “Symbiotic courtyards” not only aligns with the trend of the times, fulfilling the national policy of stock renewal and avoiding the complete demolition and reconstruction of old residential spaces, but also adds public service facilities while maintaining the overall layout, creating a better living environment and achieving sustainable development. As an innovative approach to the organic renewal of traditional courtyards, this model provides a new solution for the protection of traditional buildings. Due to its achievements in cultural continuity, it has garnered attention from various sectors of society and has been gradually promoted and practiced in the years since its introduction.

Under the promotion of public policy, the symbiotic courtyard renewal model can facilitate the coexistence of new and old buildings during the development process within old urban neighborhoods. Theoretically, this model preserves the historical significance while adding new functionalities. Therefore, the symbiotic courtyard renewal model not only restores and protects traditional buildings and their textures but also meets modern living requirements, allowing the original functions of the neighborhood to continue. At the same time, new functions such as youth apartments, office spaces, experiential courtyard hotels, or guesthouses are introduced. This brings in new residents, achieving symbiosis between old and new residents, and introduces new industries like libraries and cultural and creative industries, achieving cultural symbiosis.

The operation of symbiotic courtyards mainly involves several key steps, including government-led relocation and vacating, the transfer of usage rights, design by operating companies, and subsequent management. The renovation process of the symbiotic courtyard is shown in Figure 1. It includes both public and private houses. Public houses are collected and managed by the government. The indigenous people who own private houses return their property rights to the government; this operation is known as ‘eviction’. All houses are allocated by the government and transformed into special public rental housing, attracting social capital to join. Private companies are responsible for design and decoration, and the renovated public rental housing can be occupied by both businesses and the government. After the evacuation, residents signed agreements with the government and were resettled here by the government, ultimately forming the ideal symbiotic courtyard model.

The “symbiotic courtyard” model not only considers the protection of traditional architecture and spatial culture but also emphasizes maintaining original social relationships and social functions. It also addresses the requirements for sustainable development in social, cultural, and economic aspects of the neighborhood. From its planning principles and objectives, it can be seen as a sample and model that can lead the sustainable development of neighborhood renewal.

To date, many scholars in China have presented their views on the renovation of symbiotic courtyards. Some scholars, from an architectural perspective, have conducted on-site investigations and comparative analyses to specifically compare the advantages and disadvantages of different renovation methods for old buildings in Beijing [13]. Other scholars, based on symbiotic theory, focus on population dispersal and functional replacement within historical neighborhoods’ large courtyard complexes to rejuvenate the area [14]. A small number of scholars extend the concept of symbiosis to neighborhoods, using historical districts in Beijing or other provinces as examples to explore the feasibility of achieving symbiosis on a larger scale [15]. Although the concept of symbiotic courtyards has not been widely promoted outside Beijing, many scholars have provided clear explanations of renovation methods for old buildings elsewhere. For instance, some scholars use cases such as the upgrading of urban villages and the development of community land trusts to introduce “shared projects” and the resulting “symbiotic” relationships, capturing the cooperation between government and social actors [16,17,18,19]. Additionally, some scholars, viewing this topic from the perspectives of local residents, have explored the relationship between local governments and citizens, recognizing that heritage resources are important profit sources for cities and that their mutually beneficial symbiotic relationship has a profound impact on the physical forms of historical neighborhoods [20,21].

However, after reviewing a large number of documents, it is evident that most scholars’ research, both Chinese and international, tends to focus on broader strategic theories and localized “sharing” [22,23,24], with relatively few specialized studies on symbiotic courtyards. Moreover, many studies, although touching on related content, lack a certain degree of control over the systemic and holistic aspects of symbiotic courtyards [25,26,27]. Therefore, there is an urgent need for a comprehensive framework and research to interpret the overall renewal and protection model of symbiotic courtyards.

This paper explores the relationship between “symbiotic courtyards” and urban sustainable development from the perspective of stock renewal. By conducting field surveys, data collection, and interviews, the current usage status of existing “symbiotic courtyards” is investigated. Through methods such as questionnaires and KANO model analysis, the needs, influencing factors, and existing problems of users are analyzed. Based on these findings, optimization strategies for symbiotic courtyards are proposed to make this model more universal. Ultimately, the goal is to extend the symbiotic courtyard model to larger spatial scales, such as neighborhoods, so that it can better play a leading and exemplary role in the new era of urban renewal.

2. Material and Methods

2.1. The KANO Model

The KANO model is commonly used for classifying and prioritizing user needs, reflecting the nonlinear relationship between service quality and user satisfaction, as illustrated in Figure 2.

The service quality elements are divided into five categories: Must-Be Quality Elements (M) are essential and assumed for users. If the product does not fulfill these requirements, users will be dissatisfied. But if it is fulfilled, the customer will not show satisfaction or even be interested in the product. One-Dimensional Quality Elements (O) are conscious to the customer, eliminating dissatisfaction or achieve satisfaction depending on the degree of fulfillment—the higher the better [28]. Attractive Quality Elements (A) are not usually expected by the customer and do not disappoint them when not fulfilled [29]. Indifferent Quality Elements (I) are not noticed by the users; they cannot give either satisfaction or dissatisfaction whether fulfilled or not. Reverse Quality Elements (R) cause satisfaction when absent and dissatisfaction when present [30]. In addition to the above elements, if users both express “like” or “dislike” when having or not having this function, this phenomenon is contradictory. It is called “Questionable”.

When providing basic needs, user satisfaction does not increase but decreases if not met; when providing performance needs, user satisfaction increases but decreases if not met; when providing excitement needs, user satisfaction increases without decreasing if not met, as these are unexpected by the user; whether or not indifferent needs are met, user satisfaction remains unchanged; and when providing reverse needs, user satisfaction decreases. In practical application, the type of need is identified primarily by matching statistical data with the KANO evaluation table, as illustrated in

Table 1. Users’ Evaluation Feedback Classification Table in the KANO model.

Function/Service		Negative Questions
		Dislike (1 Point)	Live with (2 Points)	Neutral (3 Points)	Must Be (4 Points)	Like (5 Points)
Positive Questions	Dislike (1 point)	Q	R	R	R	R
	Live with (2 points)	M	I	I	I	R
	Neutral (3 points)	M	I	I	I	R
	Must be (4 points)	M	I	I	I	R
	Like (5 points)	O	A	A	A	Q

Note: A: attractive; O: one-dimensional; M: must-be, I: indifferent; R: reverse; Q: questionable.

[31].

Based on the research experience of previous scholars, the traditional classification determination process is simple but tends to produce overly absolute analysis results. This study introduced the improved Better–Worse coefficient method proposed by Berger et al. for quantitative analysis [32]. The calculation formulas are as follows:

Better = (O + A)/(M + O + A + I)

(1)

Worse = (−1) × (O + M)/(M + O + A + I)

(2)

The formulas for the Better–Worse coefficient method are as follows: In these formulas, the Better coefficient represents the level of user satisfaction when a certain need is met, while the Worse coefficient represents the level of user dissatisfaction when a certain need is not met. Referring to Lu Mingqi’s numerical judgment for classification results [33], the following is true:

−

When both the Better value and the Worse value are greater than 0.5, it is considered a one-dimensional need;

−

When both values are less than 0.5, it is considered an indifferent need;

−

When the Better value is greater than 0.5 and the Worse value is less than 0.5, it is considered an attractive need;

−

When the Better value is less than 0.5 and the Worse value is greater than 0.5, it is considered a must-be need;

The data are visualized using a four-quadrant graph to represent the demand indicators.

2.2. IPA Analysis

IPA analysis, also known as Importance–Performance Analysis, is used to evaluate the strengths and weaknesses of a company’s brand, products, and services. Users rate the importance and performance of service elements on two dimensions. The average scores are plotted on a two-dimensional coordinate system, with the vertical axis representing satisfaction and the horizontal axis representing importance. Using the overall mean score as the evaluation standard, four quadrants are formed. The specific quadrant chart is shown in Figure 3 [34].

2.3. The IPA-KANO Model

In the study of the KANO model, some scholars have pointed out that there is a nonlinear and asymmetrical relationship between factor performance and user satisfaction, meaning that improving service quality does not necessarily increase overall satisfaction. The drawback is that it does not consider the importance of service factors. Therefore, a model that combines the advantages of the KANO model and the IPA model has been proposed. Its horizontal axis is based on the explicit importance from the IPA model, and its vertical axis is based on the implicit importance from the KANO model. The model is divided into four quadrants: Keep Up the Good Work area, Additional Resource area, Low-Priority area, and Concentrate area, as shown in Figure 4 [35,36].

Regarding the degree of impact on satisfaction, Maslow’s hierarchy of needs theory posits that after basic needs are met, higher-level needs arise. In the KANO model’s classification of quality attributes, essential service quality elements correspond to low-level needs, expected service quality elements are relatively higher-level needs and rank second, and attractive service quality elements can increase user satisfaction and thus rank third. Expressed in letters, it is M > O > A > I. Reverse quality is rarely involved in the practical use of symbiotic courtyards and is therefore not considered in this paper. Within the same KANO category of service quality elements, the IPA analysis matrix is used to determine decision priorities. For the same quality element, quadrants one and two use maintenance strategies, with quadrant one taking precedence over quadrant two; quadrants three and four use improvement strategies, with quadrant four taking precedence over quadrant three.

3. Evaluation and Results

3.1. Research Area and Object

3.1.1. Symbiotic Courtyard Research Area Classification and Selection

This evaluation focuses on the “Symbiotic Courtyards” in the old urban areas of Beijing. The survey combines the definition of these courtyards with publicly available information such as media reports and the literature and conducts a preliminary survey to identify 24 research samples with the characteristics of symbiotic courtyards. According to the courtyard conditions, the newly implanted functions are divided into cultural activities, short-term homestays, and long-term residences. There are a few symbiotic courtyards with other functions that are still undergoing renovation. They constitute too few samples to be included in this evaluation. Based on the implanted functions, 24 symbiotic courtyards are summarized and organized, as seen in

Table 2. Symbiotic courtyard inserted function classification.

Inserted Function	Short-Term Homestay	Long-Term Tenancy	Cultural Activity	Etc.
Courtyard information	No. 7, Yinding Hutong No. 22, Cha’er Hutong Livable home, Cha’er Hutong No. 25,Yu’er Hutong No. 14, Gongmenkou 2nd Avenue	No. 15, Xizhuan Hutong No. 17, Xizhuan Hutong No. 39, Cuzhang Hutong No. 3, Caochang 1st Avenue No. 28, Caochang 4th Avenue No. 14, Yu’er Hutong No. 20, Yu’er Hutong	No. 30, Yu’er Hutong No. 36, Gongmenkou Hutong No. 32, Gongmenkou Hutong No. 41, Qingta Hutong Chunfengxixi Library No. 31, Chuziying No. 8, Cha’er Hutong No. 19, Cha’er Hutong No. 27, Neiwubu Street	Xiaotangfang Hutong (business, work) Nos. 1–2, Cha’er Hutong (Green micro-renewal) Saloon, Baimasi district (public)

. Their characteristics are also classified for study.

3.1.2. Symbiotic Courtyard Users’ Classification and Selection

Symbiotic courtyards’ implementation has already taken shape. By investigating the degree of user needs and satisfaction, the opinions of users on the implementation of symbiotic courtyards are summarized, the key points of symbiotic courtyard construction are summarized, and the needs of various groups in different models of symbiotic courtyards are studied to understand the importance and satisfaction of users with various functions. To gain a deeper understanding of the construction and current usage of symbiotic courtyard buildings and spaces, the survey team chose three symbiotic courtyards randomly sampled from all courtyards in the three classifications above, “No. 7, Yinding Hutong” in “Short-term homestay”; No. 3, “Caochang 1st Avenue” in “Long-term homestay”; and “No. 8 Cha’er Hutong” in “Cultural activity”. All three courtyards are located in the core area of the capital, which contains the historical and cultural conservation areas, as shown in Figure 5.

The team surveyed these courtyards through data collation and on-site inspections. This survey interviewed all 24 households in 3 symbiotic courtyards, including old residents, new residents, and potential users (came to experience), covering different age groups and professional identities, as shown in Figure 6. The aim was to comprehensively collect the needs and satisfaction evaluations of relevant personnel. Old residents refer to those who have lived in the alleys for a long time, new residents refer to those who have moved in from outside the alleys, and potential users refer to those who may become new residents. Later data analysis was divided into two types based on different methods: ① users of different courtyards and ② old residents, new residents, and potential users (

Table 3. Respondents’ information overview.

	Short-Term Homestay	Long-Term Tenancy	Cultural Activity
Old Resident	Two families who have lived here for over 100 years	8 households	Households
New Resident	Short-term tourists	Long-term tenants	Surrounding residents/Artists
Potential User	Surrounding tourists	Surrounding users	Surrounding residents/Cultural enterprises

).

3.2. Construct Evaluation Index System

Currently, there is little research on the symbiotic courtyards’ and flat areas’ evaluation. But, as a part of the core urban area, they can be considered by studying the relevant literature and existing evaluation systems, as detailed in

Table 4. Symbiotic courtyard’s evaluation index division.

Primary Index	Secondary Index	Related Researcher
Spatial fusion	Layout flow, Yard facilities, Indoor function, Indoor environment	Tong Zhen, Zhou Jin, Huang Jianzhong, etc.
	Structural reinforcement, Technical update, Pipeline	Dai Guoying, Li Haipeng, etc.
Functional coordination	Public service, Commercial function, Residential function	Bu Huimin, Zhu Rui, Yao Fan, etc.
	Private space, Shared space	Jian Xia, Han Xili, Dong Yinan, etc.
Humanistic harmony	Historical environment, Modern element, Cultural belonging, Cultural identity, Neighborhood atmosphere, Cultural vitality, Settle stability	Zhang Jindong, Wang Chunhui, Liang Qiao, Hu Shaoxue, etc.
Cooperative management	Government support, Developer management, Public participation, Operation maintenance, Designer participation	Wang Hai, Jiang Difei, Zhang Yanling, Xiao Dawei, etc.

. Drawing on the construction principles of spatial evaluation related to urban public spaces, urban historical districts, and villages, combined stock renewal and, based on the attributes of the old city and specific actual surveys, evaluation factors are screened to establish an evaluation index system. After screening the relevant literature, the characteristics of the symbiotic theory are summarized into 4 major categories and 24 sub-items: spatial fusion, functional coordination, humanistic harmony, and cooperative management. Each question in the questionnaire targets a specific aspect, collecting ratings for need level, importance, and satisfaction [37,38,39,40,41,42,43,44,45].

3.3. Symbiotic Courtyard Model Evaluation Results

3.3.1. IPA-KANO Model Evaluation Analysis

The results of the survey are summarized in

Table 5. The KANO model analysis results.

Function/Service	A	O	M	I	R	Q	Results	Better	Worse
Layout flow	37.50%	4.17%	25.00%	33.33%	0.00%	0.00%	Attractive	41.67%	−29.17%
Yard facilities	41.67%	25.00%	8.33%	25.00%	0.00%	0.00%	Attractive	66.67%	−33.33%
Indoor function	0.00%	50.00%	37.50%	12.50%	0.00%	0.00%	One-dimensional	50.00%	−87.50%
Indoor environment	16.67%	29.17%	37.50%	16.67%	0.00%	0.00%	Must-be	45.83%	−66.67%
Structural reinforcement	0.00%	8.33%	66.67%	25.00%	0.00%	0.00%	Must-be	8.33%	−75.00%
Technical update	58.33%	0.00%	0.00%	41.67%	0.00%	0.00%	Attractive	58.33%	0.00%
Water and electricity pipeline	4.17%	16.67%	66.67%	12.50%	0.00%	0.00%	Must-be	20.83%	−83.33%
Public service	12.50%	4.17%	12.50%	29.17%	41.67%	0.00%	Reverse	28.57%	−28.57%
Commercial function	16.67%	0.00%	0.00%	29.17%	50.00%	4.17%	Reverse	36.36%	0.00%
Residential function	0.00%	0.00%	45.83%	50.00%	4.17%	0.00%	Indifferent	0.00%	−47.83%
Private space	4.17%	29.17%	45.83%	20.83%	0.00%	0.00%	Must-be	33.33%	−75.00%
Shared space	8.33%	45.83%	8.33%	37.50%	0.00%	0.00%	One-dimensional	54.17%	−54.17%
Historical environment	20.83%	58.33%	8.33%	12.50%	0.00%	0.00%	One-dimensional	79.17%	−66.67%
Modern culture element	20.83%	4.17%	4.17%	70.83%	0.00%	0.00%	Indifferent	25.00%	−8.33%
Cultural belonging	37.50%	29.17%	16.67%	16.67%	0.00%	0.00%	Attractive	66.67%	−45.83%
Cultural identity	20.83%	33.33%	29.17%	16.67%	0.00%	0.00%	One-dimensional	54.17%	−62.50%
Neighborhood atmosphere	20.83%	50.00%	16.67%	12.50%	0.00%	0.00%	One-dimensional	70.83%	−66.67%
Cultural vitality	41.67%	25.00%	4.17%	25.00%	0.00%	4.17%	Attractive	69.57%	−30.43%
Settle stability	12.50%	25.00%	8.33%	50.00%	4.17%	0.00%	Indifferent	39.13%	−34.78%
Government support	12.50%	25.00%	45.83%	16.67%	0.00%	0.00%	Must-be	37.50%	−70.83%
Developer management	12.50%	8.33%	8.33%	62.50%	8.33%	0.00%	Indifferent	22.73%	−18.18%
Public participation	41.67%	25.00%	4.17%	29.17%	0.00%	0.00%	Attractive	66.67%	−29.17%
Designer participation	33.33%	25.00%	16.67%	25.00%	0.00%	0.00%	Attractive	58.33%	−41.67%
Operation maintenance	20.83%	29.17%	33.33%	16.67%	0.00%	0.00%	Must-be	50.00%	−62.50%

Note: A: attractive; O: one-dimensional; M: must-be; I: indifferent; R: reverse; Q: questionable.

, and the 24 elements of symbiotic courtyard service quality are classified. Among them, the layout flow, courtyard facilities, technical updates, cultural belonging, cultural vitality, public participation, and designer participation were classified as attractive elements, accounting for 29.2%; the indoor functions, shared spaces, historical environment, cultural identity, and neighborhood atmosphere were classified as one-dimensional elements, accounting for 20.8%; the indoor environment, structural reinforcement, pipelines, private spaces, government support, and operation maintenance were classified as must-be elements, accounting for 25%; the residential functions, modern cultural elements, settle stability, and developer management were classified as indifferent elements, accounting for 16.7%; and the commercial functions and public services were classified as reverse elements, accounting for 8.3%.

According to the questionnaire data statistics, the results are shown in Figure 7. Historical environment, neighborhood atmosphere, cultural identity, shared space, operation maintenance, indoor environment, and indoor function are located in Quadrant 1, which are the Keep Up the Good Work areas. Cultural vitality, cultural belonging, courtyard facilities, designer participation, public participation, and technical renewal are located in Quadrant 2, which are the Additional Resource areas. Layout flows, settle stability, public services, commercial functions, modern cultural elements, developer management, and residential functions are located in Quadrant 3, which are the Low-Priority areas for later improvement. Private space, government support, pipelines, and structural reinforcement are located in Quadrant 4, which are the Concentrate area that needs to be improved.

3.3.2. Identify Service Quality Elements’ Priority

The most important are the Keep Up the Good Work area, followed by the Additional Resource Area, Concentrate area, and finally the Low-Priority area. Therefore, in the IPA-KANO model, the importance of advantage zone elements is the highest. The factors within this quadrant need to be prioritized for improvement, with increased resource investment in these types of factors. For the same KANO attribute and the same IPA quadrant quality elements, when the importance/satisfaction (I/P) is large, it indicates higher importance and lower satisfaction, thus taking precedence over quality elements with lower importance/satisfaction (I/P). By sorting out their models, a mechanism for enhancing the service quality of symbiotic courtyards is derived. The specific distribution results are shown in the Figure 8.

When determining the specific order, the priority is initially determined through a comprehensive analysis of KANO attributes and IPA quadrants. The improvement strategy priority order and the size of I/P are used to determine the service quality element priority within the same KANO attribute and the same IPA quadrant. If the ratio is larger, the quality element is more important, and satisfaction is lower, so its priority is higher; if the ratio is smaller, it indicates that the quality element is relatively less important and satisfaction is higher, so its priority is lower. The specific data conclusion analysis is shown in

Table 6. Symbiotic courtyard service element prioritization.

Service Quality Element Number	Classification	Current Satisfaction	Perceived Importance	I/P	Improvement Order	Keep Order
Layout flow	A	2.63	3.54	1.35		5
Yard facilities	A	3.17	3.71	1.17	8
Indoor function	O	3.25	4.67	1.44	1
Indoor environment	M	3.21	4.58	1.43	2
Structural reinforcement	M	3.50	2.96	0.84		2
Technical update	A	3.04	2.33	0.77	10
Water and electricity pipeline	O	3.21	4.17	1.30	3
Public service	R	2.88	2.13	0.74		——
Commercial function	R	2.58	2.29	0.89		——
Residential function	I	3.13	3.79	1.21	4
Private space	M	2.46	4.25	1.73	6
Shared space	O	2.83	3.79	1.34		5
Historical environment	O	4.08	4.42	1.08		6
Modern culture element	I	3.54	2.71	0.78		4
Cultural belonging	A	3.63	3.58	0.99		7
Cultural identity	O	3.46	3.13	0.90		1
Neighborhood atmosphere	O	3.25	4.33	1.33	7
Cultural vitality	A	3.63	3.00	0.82		3
Settle stability	I	2.92	2.96	1.01		8
Government support	M	3.00	3.71	1.24	9
Developer management	I	2.92	2.88	0.99		9
Public participation	A	3.21	2.79	0.87		10
Designer participation	A	3.29	2.71	0.82		11
Operation maintenance	M	2.79	4.29	1.54	5

.

4. Discussion

4.1. Users’ Requirement Type Analysis

Through the survey and analysis, symbiotic courtyard users can be studied in two main aspects based on the functional mode of the courtyards and the needs of new and old residents. Among them, the different functional modes of symbiotic courtyards are studied according to the implementation of long-term residence, commercial homestay, and cultural activity functions, while new and old users are classified into old residents, new residents, and potential users. This paper hopes to provide support and basis for the improvement and promotion of symbiotic courtyards by studying the types and importance of user needs.

4.1.1. Different Symbiotic Courtyard Models’ Users Needs Priority

Users’ needs and preferences also show significant differences because of the different symbiotic models of three courtyards, as shown in Figure 9. Overall, they can be summarized into four points.

First is the difference in shared space needs: Courtyards with settled residents have a strong demand for private space, emphasizing practical issues such as flow layout and functional arrangement. Courtyards with a public cultural nature have a strong demand for shared spaces, emphasizing factors such as neighborhood atmosphere, cultural identity, and a sense of belonging.

Second is the difference in expected residence time: long-term residents prefer stable residents, while public cultural courtyards favor short-term tourists.

The third point is the difference in developer-led design needs: courtyards primarily for long-term residence prefer collaborative design, while public cultural courtyards favor developer and primary design, with higher attractiveness demands for government support and planner involvement.

The fourth point is the difference in function implantation needs: courtyards with strong public nature are more inclusive of commercial and service industries than residential courtyards, with a reduced proportion of basic needs and a significant increase in the proportion of attractive and expected needs.

4.1.2. New or Old Residents and Potential Users’ Needs Priority

Whether new or old residents and potential users have different uses, emotions, and needs for symbiotic courtyards, there are demand differences, as shown in Figure 10. Specifically, there are four points.

First is the difference in historical and modern cultural needs: Old residents have a strong emotional demand for historical culture, especially expecting the preservation of historical environmental elements, enhancement of cultural belonging, and improvement of neighborhood atmosphere. They have a neutral attitude towards modern culture, while new residents have a more unified attitude towards cultural vitality and modern cultural elements, expecting a combination of modern and historical culture.

The second point is the difference in public service needs: New residents prefer courtyards with public service functions and have a higher demand for shared spaces. Old residents pay more attention to private spaces and regard shared demand as a neutral need to a greater extent.

The third point is the difference in building technology and structure needs: new residents generally pursue higher quality of life, expecting the integration of new technologies and structures with old buildings.

The fourth point is the difference in building design needs: new residents generally consider a good landscape environment and high-end architectural design as basic needs, with the quality of life matching the high land prices. Potential users also tend to choose basic needs such as a good spatial environment, historical environmental elements, and modern residential functions.

Based on the comprehensive analysis of all user needs, four types of needs and their commonalities among residents can be summarized as follows (as illustrated in Figure 11):

4.2. “Importance-Satisfaction” Analysis

Based on the KANO model, further exploration of the relationship between the importance and satisfaction of various needs was conducted. Using the Importance–Satisfaction model can compared the key concerns and satisfaction-related issues with the renovation outcomes among users of the three types of courtyards. The findings indicate the primary focus areas for future improvements. The analysis results for the three courtyards are shown in Figure 12.

As shown in the figure, respondents in Caochang Hutong have the highest level of satisfaction, with an average score of 3.6. The overall renovation of the district is relatively comprehensive, and satisfaction with various needs is high. The material environment quality of the symbiotic courtyards in this area is the highest, and residents have a significant sense of happiness and cultural confidence. Next, private open spaces should be increased on the basis of existing shared courtyards. In addition, the community’s public welfare, service facilities, and commercial facilities need further improvement.

The respondents in Cha’er Hutong have the lowest level of satisfaction, with an average score of 2.9. The overall renovation of the block is less extensive, and the material and cultural environments are poor. The advantage of this area lies in its strong historical environment atmosphere, reflecting the memory and characteristics of contemporary alleys. However, infrastructure construction is relatively weak, requiring government and enterprise efforts to promote the renovation of symbiotic courtyards, improve indoor functions, enhance indoor environments, and strengthen daily operation and management.

The respondents in Yin Dingqiao Hutong have moderate satisfaction, with an average score of 3.0. The block is located in a conservation area with a relatively conservative renovation approach. Residents value the alley cultural atmosphere and are relatively satisfied, with a good neighborhood atmosphere being present. However, the “Residence + Homestay” model should reasonably handle the flow lines and spatial relationships between tourists and original residents, with enterprises strengthening management. The frequent changes in homestay guests and varying qualities have negatively impacted the original residents, and long-term fixed rental methods should be considered.

By calculating the average satisfaction and importance values to differentiate the four quadrants, the average satisfaction is 3.1 and the average importance is 3.4.

4.3. User Requirements Summary

This evaluation analyzes the needs of users living in three types of symbiotic courtyards, using the IPA-KANO model to study the types, importance, and satisfaction ratings of users’ needs. It summarizes the demand characteristics of different users and identifies the strengths, improvement directions, and key issues for each courtyard. To achieve sustainability and symbiosis in the construction of symbiotic courtyards, spatial integration is the foundation, functional coordination is the focus, cultural harmony is the highlighted aspect, and cooperative management is the support.

1.

Spatial Integration is the Foundation of Architectural Symbiosis: Integrating the old and new physical environments can enhance the quality of architectural spaces. The primary task is to meet the basic living needs of users and then to meet the high-quality living needs of new residents.

2.

Functional Coordination is the Method of Architectural Symbiosis: Combining public and private functions can reduce user satisfaction, so it is important to properly handle the relationship between public and private functions.

3.

Cultural Harmony is the Manifestation of Cultural Symbiosis: It can provide a sense of belonging for old residents and a sense of identity for new residents, forming a good neighborhood atmosphere. Symbiotic courtyards have achieved significant results in this aspect.

4.

Cooperative Management is the Method of Symbiosis between Old and New Residents: It is an important support for the symbiotic courtyard renovation model. Multi-party participation in joint planning and negotiation is a key factor in promoting the sustainable model of symbiotic courtyards.

4.4. Symbiotic Courtyard Model’s Sustainable Optimization Strategy

4.4.1. Define Symbiosis Clearly and Strengthen Policy Support

The government should define symbiotic courtyards’ characteristics and standards clearly, specifying the essential elements (such as original residents) and potential elements (such as implanted functions) of the symbiotic units. It is also important to incorporate the time dimension and pay attention to the phased changes in courtyard symbiosis, as shown in Figure 13. Policy-wise, the government should ensure that the policies are actionable and support the use and management of vacated assets as soon as possible.

4.4.2. Improve Symbiotic Construction and Adhere to Cultural Heritage

The symbiotic courtyard model needs to implement improvements in basic facilities such as kitchens and bathrooms, which requires both updates to the courtyard design and overall block pipeline upgrades. The model should prioritize cultural heritage, enhancing the cultural connotation and identity of the courtyards. Architectural space design should increase resident participation and government oversight.

4.4.3. Coordinate Symbiotic Functions and Focus on Humanistic Needs

The purpose of the symbiotic courtyard model is to collaborate with professional designers and enterprises based on the wishes of residents in order to carry out better updated designs. As shown in Figure 14, the rationality of symbiotic functions is crucial for achieving a win–win situation between individual and overall interests. Multiple parties should actively protect traditional culture and improve living conditions, increasing publicity and social attention.

4.4.4. Enhance Symbiotic Roles and Boost District Vitality

Symbiotic courtyards should ensure a sustainable role in the district, considering both spatial and temporal dimensions, as shown in Figure 15. Micro-updates in historical district are dynamic protection and updates based on adaptability, generating social and economic benefits [45,46]. So, it is necessary to promote the upgrading of symbiotic courtyards to symbiotic districts, where the overall improvement of the district is a prerequisite for the sustainability of symbiotic courtyards.

5. Conclusions

This paper takes stock renewal as the perspective and uses the IPA-KANO model to analyze the needs of symbiotic courtyard users, examining the types, importance, and satisfaction of users’ needs. It summarizes the demand characteristics of different users and identifies the strengths, improvement directions, and key issues for each courtyard. To achieve sustainability and symbiosis in the construction of symbiotic courtyards, attention must be paid to spatial integration, functional coordination, cultural harmony, and cooperative management.

In order to achieve symbiotic courtyards’ sustainable development, this paper proposes the following strategies: focus on protecting architectural space design to meet user needs, introduce various business formats according to local conditions to avoid homogenization, and pay attention to publicity and community building to balance commercial development and protection. The analysis reveals that symbiotic courtyards perform well in preserving historical cultural features and meeting user needs, but still need to address issues such as the frequent updates to and redecorations of some courtyards and the need for improved social and economic benefits.

Overall, Beijing’s symbiotic courtyard model has achieved good results in practice. Through evaluations of cultural heritage and innovation, community renewal and resident participation, green and low-carbon sustainable development, functional optimization and spatial enhancement, and social and economic benefits, it is of importance to see that this renovation model has significant reference value for urban stock renewal. However, there are also challenges such as funding and policy support that need further exploration.