Integration of Building Information Modeling (BIM) and Big Data in China: Recent Application and Future Perspective

: The integrated application of building information modeling (BIM) and big data (BD) has received widespread attention, and has been involved in smart construction sites, construction project management, and construction project budgeting. Nevertheless, research on the integrated implementation of BIM and BD in China mainly concentrates on a project stage or profession, the exploration of technology integration mostly focuses on the theoretical level, and the research distribution is scattered. As such, the intention of this paper is to reveal the research history of BIM and BD in China, as well as to study the research methodologies and research ﬁelds for a more thorough knowledge of the BIM and BD research and development status in the Chinese construction sector, which adopts a mixed research method that uses a quantitative research via two analytical software tools, i.e., CiteSpace version of 6.1.R6 and the Statistical Analysis Toolkit on line edition for Informetrics software packages, to conduct a macro bibliometric analysis on BIM and BD research in the China National Knowledge Infrastructure database, and provides a follow-up micro qualitative research with content analysis. To ensure the comprehensiveness of the research, the core articles of the topic in the web of science database have been sorted out and analyzed for fully understanding the development of BIM and BD in the ﬁeld of Chinese construction, resulting in identifying the current research hotspots and trends in China. The results suggest that the popular research keywords on BIM and BD in China since the year 2015 have mainly been focused on informatization, the internet of things, and rail transportation. Three fruitful research themes in BIM and BD research in China have been identiﬁed, including smart construction, smart operation, and bridge informatization.


Introduction
The construction industry has a significant importance as a fundamental sector in China, contributing to the nation's economic development.As the Chinese government invests more in infrastructure construction and pays more and more attention to the quality management of construction projects, the difficulty of project management also increases.In the year 2016, China's Ministry of Housing and Construction released the "Outline of the Development of Construction Industry Informatization from 2016 to 2020" [1], which clearly states that integrating building information modeling (BIM) and big data (BD) technology should be enhanced.Through the integration of BIM and BD, the value data in construction information are mined to promote the intelligent management and smart decision making of construction projects.
The concept of BIM was first introduced by Eastam in the 1970s [2] as a digital representation of the physical and functional characteristics of buildings based on three-dimensional This paper employs a mixed research method, conducting a macro bibliometric analysis on BIM and BD research in China National Knowledge Infrastructure (CNKI) by applying two analytical software tools, CiteSpace and Statistical Analysis Toolkit for Informetrics (SATI), providing follow-up micro qualitative research with content analysis, and combining this with the literature analysis from the database of Web of Science (WoS) to gain a comprehensive in-depth understanding of the development of BIM and BD in the Chinese construction industry.The CNKI database was used as a data source in the article, and all journal papers with "Topic = 'BIM' and Topic = 'Big Data'" were obtained.To make the literature sample more representative, the data sources Engineering Index (EI), Peking University Core, Chinese Social Sciences Citation Index (CSSCI), and Chinese Science Citation Database (CSCD) were chosen, and the search date was selected as 1 January 2023, resulting in 89 valid articles as the research sample.CiteSpace is a bibliometric analysis software for tracking and analyzing international frontier research, which is able to visualize the relationships between the literature as a scientific knowledge map that can help to sort out past research trials as well as enable having a general idea of future research perspectives [12].SATI is a popular tool for statistically analyzing bibliographic data in end-note format.This paper combines CiteSpace and SATI to conduct a multi-dimensional comparison and analysis of the literature data in order to create a knowledge map of BIM and BD research, identify hot areas of research and trends on BIM and BD, and provide a point of reference for further exploration of BIM and BD in China.
The research flow chart for this study is shown in Figure 1, which includes the five phases below: (1) Identifying the research topic, retrieving the relevant works of the literature with keywords of BIM and BD.(2) Literature analysis and visualization of results regarding BIM and BD.
(3) Relationship analysis on BIM and BD through CiteSpace software tool.(4) Research history analysis and future research tendency prediction on BIM and BD using CiteSpace software tool.(5) Micro analysis of research trends and methods in the field of BIM and BD.
dimensional comparison and analysis of the literature data in order to create a knowl map of BIM and BD research, identify hot areas of research and trends on BIM and and provide a point of reference for further exploration of BIM and BD in China.
The research flow chart for this study is shown in Figure 1, which includes the phases below: (1) Identifying the research topic, retrieving the relevant works of the literature keywords of BIM and BD.(2) Literature analysis and visualization of results regarding BIM and BD.
(3) Relationship analysis on BIM and BD through CiteSpace software tool.(4) Research history analysis and future research tendency prediction on BIM an using CiteSpace software tool.(5) Micro analysis of research trends and methods in the field of BIM and BD.

General Information
As demonstrated in Figure 2, the research on BIM and BD in China began in the 2015 and has gradually developed since then.The number of articles from the CNKI database published in China regarding BIM and BD started to increase significantly 2017, with the number of articles consistently above 10 per year from 2018 onwards

General Information
As demonstrated in Figure 2, the research on BIM and BD in China began in the year 2015 and has gradually developed since then.The number of articles from the CNKI core database published in China regarding BIM and BD started to increase significantly from 2017, with the number of articles consistently above 10 per year from 2018 onwards, and reaching the peak at 20 in 2021.The growth can be attributed to the issuance of the "Outline for the Development of Informatization in the Construction Industry from 2016 to 2020" by China's Ministry of Housing and Urban-Rural Development in 2016 [1].This policy document emphasizes the need to enhance the development capacity of informatization in the construction industry through the integration of various information technologies, including BIM, BD, intelligence, mobile communication, and cloud computing.The aim is to achieve the integrated application of BIM and enterprise management information systems, thereby promoting the improvement of design and management levels within enterprises.Current research on BIM and BD in China is based on a single aspect, staying at a certain stage and a certain field, and the exploration of multi-technology integration mostly staying at the level of theoretical analysis; as such, the integration of BIM technology with other technologies in China still needs further development [11].The research related to BIM and BD in China will continue to grow until it becomes mature in the future.
reaching the peak at 20 in 2021.The growth can be attributed to the issuance of the "Outline for the Development of Informatization in the Construction Industry from 2016 to 2020" by China's Ministry of Housing and Urban-Rural Development in 2016 [1].This policy document emphasizes the need to enhance the development capacity of informatization in the construction industry through the integration of various information technologies, including BIM, BD, intelligence, mobile communication, and cloud computing.The aim is to achieve the integrated application of BIM and enterprise management information systems, thereby promoting the improvement of design and management levels within enterprises.Current research on BIM and BD in China is based on a single aspect, staying at a certain stage and a certain field, and the exploration of multi-technology integration mostly staying at the level of theoretical analysis; as such, the integration of BIM technology with other technologies in China still needs further development [11].The research related to BIM and BD in China will continue to grow until it becomes mature in the future.

Research Topic and Journal Source
As illustrated in Figure 3, a total of 89 publications across a range of 19 disciplines have been acquired in this review of the distribution of Chinese research on BIM and BD, of which, the majority of the articles are about building science and engineering with 38 articles (26.57%), followed by computer software and computer application with 33 articles (23.08%), road and waterway transportation with 24 articles (16.78%), railway transport with 11 articles (7.69%), and water resources and hydropower engineering with 7 articles (4.90%).

Research Topic and Journal Source
As illustrated in Figure 3, a total of 89 publications across a range of 19 disciplines have been acquired in this review of the distribution of Chinese research on BIM and BD, of which, the majority of the articles are about building science and engineering with 38 articles (26.57%), followed by computer software and computer application with 33 articles (23.08%), road and waterway transportation with 24 articles (16.78%), railway transport with 11 articles (7.69%), and water resources and hydropower engineering with 7 articles (4.90%).
In addition, as shown in Figure 4, the distribution of published papers of the top 10 journals in the CNKI database from 2015 to 2022 has been identified, and the most frequently published journals in the area of BIM and BD research in China are "Construction Economy" with ten articles (23.81%), followed by "Tunnel Construction" with seven articles (16.67%), and "Industrial Construction" with five articles (11.9%).In general, in China, the distribution of the literature on the study issue of BIM and BD is mostly concentrated on the fields of road tunnels, industrial buildings, water conservation, and hydropower.In addition, as shown in Figure 4, the distribution of published papers of the top 10 journals in the CNKI database from 2015 to 2022 has been identified, and the most frequently published journals in the area of BIM and BD research in China are "Construction Economy" with ten articles (23.81%), followed by "Tunnel Construction" with seven articles (16.67%), and "Industrial Construction" with five articles (11.9%).In general, in China, the distribution of the literature on the study issue of BIM and BD is mostly concentrated on the fields of road tunnels, industrial buildings, water conservation, and hydropower.In addition, as shown in Figure 4, the distribution of published papers of the top 10 journals in the CNKI database from 2015 to 2022 has been identified, and the most frequently published journals in the area of BIM and BD research in China are "Construction Economy" with ten articles (23.81%), followed by "Tunnel Construction" with seven articles (16.67%), and "Industrial Construction" with five articles (11.9%).In general, in China, the distribution of the literature on the study issue of BIM and BD is mostly concentrated on the fields of road tunnels, industrial buildings, water conservation, and hydropower.

Research Institutions
CiteSpace software was used to do a macro analysis on the 89 core papers collected during data collection.Research institutions with more than three publications were selected for analysis, as shown in Table 1.Tongji University is the institution with the highest number of papers published in the field of BIM and BD research in China, with a total of six papers, followed by the China Academy of Railway Sciences, Shenzhen University, Tsinghua University, Southwest Jiaotong University, and Beijing Jiaotong University, which have an important influence on the promotion of BIM and BD in construction in China.
By analyzing the research keywords of the institutions, it is revealed that the core research institutions in the subject area of BIM and BD in China mainly focus on the intelligent construction, intelligent operation, and maintenance of heavy-duty railways, energy consumption monitoring, bridge informatization, and railway shield tunnels.

Research Institutions
CiteSpace software was used to do a macro analysis on the 89 core papers collected during data collection.Research institutions with more than three publications were selected for analysis, as shown in Table 1.Tongji University is the institution with the highest number of papers published in the field of BIM and BD research in China, with a total of six papers, followed by the China Academy of Railway Sciences, Shenzhen University, Tsinghua University, Southwest Jiaotong University, and Beijing Jiaotong University, which have an important influence on the promotion of BIM and BD in construction in China.
In order to understand the co-operative relationship between BIM and BD research institutions in China, the CiteSpace software package has been employed to generate the co-operative co-occurrence graph, as shown in Figure 6, in which the size of the labels reflects the number of publications, the size of the nodes represents the frequency of occurrence, the lines between the nodes indicate the co-operative relationship, and the thickness of the lines suggests the intensity of co-operation [12].As shown in Figure 6    Moreover, the centrality of a keyword is primarily used to evaluate the significance of a node in the keyword co-occurrence map [12].A keyword with a centrality value greater than or equal to 0.1 indicates that the keyword is highly central and has an important effect on the keyword co-occurrence map [13].In Table 2, the keywords with a centrality greater than or equal to 0.1 are Big Data (0.3), Informatization (0.13), Internet of Things (0.1), and Rail Transport (0.1), revealing that these keywords have significant importance in the research on BIM and BD in China.Moreover, the centrality of a keyword is primarily used to evaluate the significance of a node in the keyword co-occurrence map [12].A keyword with a centrality value greater than or equal to 0.1 indicates that the keyword is highly central and has an important effect on the keyword co-occurrence map [13].In Table 2, the keywords with a centrality greater than or equal to 0.1 are Big Data (0.3), Informatization (0.13), Internet of Things (0.1), and Rail Transport (0.1), revealing that these keywords have significant importance in the research on BIM and BD in China.
Furthermore, the results of the keyword co-occurrence map (Figure 7) and the frequency and centrality statistics table (Table 2) indicate that the keyword "Big Data" has the highest frequency and centrality in the co-occurrence map, and is the most concentrated in relation to other keywords.Similarly, "Internet of Things" and "Informatization" have both a high frequency and a high centrality, highlighting the central research topics in the field of BIM and BD in China from 2015 to 2022.This paper uses the Log-likelihood Rate (LLR) algorithm in CiteSpace to cluster the papers in BIM and BD, resulting in the top four clusters in a keyword clustering map, as shown in Figure 8, in which the Modularity clustering module value (Q value) is equal to 0.7897, where it is generally considered that Q > 0.3 means that the clustering structure is significant, and the Silhouette clustering average profile value (S value) equals 0.9439, where S > 0.5 clustering is generally considered to be reasonable and S > 0.7 implies that the clustering is convinced [12].As shown in Figure 8  In the cluster of artificial intelligence, the main research concerns smart construction [22], smart design [23], and smart detection [24].As a core driver of the next generation of industrial change, artificial intelligence is an important method to comprehensively improve digitalization, automation, informatization, and intelligence in civil engineering, and has gained widespread attention [23].China is one of the earliest and fastest moving countries in the world within the field of artificial intelligence.Since 2015, China has promulgated policies such as Made in China 2025 [25], the Guidance on Actively Promoting Internet+ Action [26], The National 13th Five-Year Plan for the Development of Strategic Emerging Industries [27], and the Next Generation Artificial Intelligence Development Plan [28], which have planned the key development directions of artificial intelligence in detail from various aspects and clearly stated that artificial intelligence is the core technology of the next round of scientific and technological revolution and industrial transformation.Through aligning the above policies, from 2015, related research has been conducted, such as the digitalization of shield tunnels [22], bridge informatization and intelligent bridges [29], intelligent geotechnical engineering [30], an intelligent construction-integrated management system [31], and the green construction of metro underground stations [32].In the big data cluster, the main research topics include big data [14], internet+ [15], and intelligent management [10].Under the wave of global digitization, theoretical and applied research on the integration of BD and the real economy have been expanding, and the effect of using big data to enhance the transformation and upgrading capabilities of enterprises and business values has been gradually demonstrated in some industry sectors, but research and development and application in the field of engineering projects are relatively lagging behind [13].In addition, since BD technology is constantly evolving, Chinese academics are becoming more and more interested in the integrated use of BIM and BD.Relevant research areas include the directions of engineering project management innovation [14], major engineering organization system integration models [16], underground engineering monitoring [17], rail transportation management [18], tunnel construction management [19], water transport engineering construction [20], and engineering bidding and procurement [21].
In the cluster of artificial intelligence, the main research concerns smart construction [22], smart design [23], and smart detection [24].As a core driver of the next generation of industrial change, artificial intelligence is an important method to comprehensively improve digitalization, automation, informatization, and intelligence in civil engineering, and has gained widespread attention [23].China is one of the earliest and fastest moving countries in the world within the field of artificial intelligence.Since 2015, China has promulgated policies such as Made in China 2025 [25], the Guidance on Actively Promoting Internet+ Action [26], The National 13th Five-Year Plan for the Development of Strategic Emerging Industries [27], and the Next Generation Artificial Intelligence Development Plan [28], which have planned the key development directions of artificial intelligence in detail from various aspects and clearly stated that artificial intelligence is the core technology of the next round of scientific and technological revolution and industrial transformation.Through aligning the above policies, from 2015, related research has been conducted, such as the digitalization of shield tunnels [22], bridge informatization and intelligent bridges [29], intelligent geotechnical engineering [30], an intelligent construction-integrated management system [31], and the green construction of metro underground stations [32].
In the IoT cluster, the main research focuses on the IoT [31], cloud computing [33], and smart buildings [34].The IoT is a network that connects any object to the internet for information exchange and communication according to an agreed protocol through information sensing devices such as Quick Response (QR) code reading devices, radio frequency identification devices, infrared sensors, global positioning systems, and laser scanners, in order to achieve intelligent identification, positioning, tracking, monitoring, and management [35].In recent years, IoT technology has become more popular since its value when integrated with BIM applications has become increasingly recognized and has been used to design an IoT-BIM management platform to cope with the needs of actual projects.In addition, more and more engineering projects have employed the IoT-BIM platform for on-site projects [36].With the constant investigation and application of a new generation of internet technologies in the construction sector, such as BD, IoT, cloud computing, and so on, the idea of smart building has developed.Smart building is implemented as a total solution to buildings, people, and the environment using computer technology, internet technology, and other technical support to provide a safe, efficient, and comfortable environment, with the building having a lower energy consumption via a smart design, smart construction, and intelligent operation and maintenance throughout the whole life cycle of the building [34].The related research directions have been associated with the digitization of road infrastructure [37], smart hospital project construction and operation management [38], the smart management of expansion projects [39], and the smart control of reconstruction projects [40].
In the cluster of informatization, the research has been conducted on informatization [41], hyperforecasting [42], processing control [8], a digital twin [43], and data application [44].The current internet plus and big data information era has proposed a whole new challenge to big data information technology in the survey and design industry.Moreover, the use of cloud computing technology for obtaining information data or mining related information to achieve unification between data islands, standardized correlations, and the cross-use of data have been conducted to abandon the search for causal relationships between information data.This results in a focus on the correlation of information data, meaning the unity between information data and people, production, policies, and profits and between information data and business processes, to provide an accurate, comprehensive, and more realistic predictive analysis, and assist decision making for enterprise decision making and management [44].The related research has been highlighted in the informatization of water transfer projects [43], the digitalization of water conservancy and hydropower projects [41], geological forecasting [42], and engineering data management [8].

Keyword Burst Analysis
The analysis of CiteSpace's keyword burst can provide an understanding of the hotspot evolution and research frontiers of a certain research area over a period of time [12].As shown in Figure 9, Chinese scholars began to put their research focus on the integration of BIM and BD, with BIM taking root in China and there being a gradual increase in national investment in high-tech research and development in 2015.
unity between information data and people, production, policies, and profits and between information data and business processes, to provide an accurate, comprehensive, and more realistic predictive analysis, and assist decision making for enterprise decision making and management [44].The related research has been highlighted in the informatization of water transfer projects [43], the digitalization of water conservancy and hydropower projects [41], geological forecasting [42], and engineering data management [8].

Keyword Burst Analysis
The analysis of CiteSpace's keyword burst can provide an understanding of the hotspot evolution and research frontiers of a certain research area over a period of time [12].As shown in Figure 9, Chinese scholars began to put their research focus on the integration of BIM and BD, with BIM taking root in China and there being a gradual increase in national investment in high-tech research and development in 2015.In 2015, Hou [45] put forward the development outlook of BIM informatization, in which BIM would open up the era of big data for the construction industry.In addition, it has been defined as a management platform that could be applied to all stages of the In 2015, Hou [45] put forward the development outlook of BIM informatization, in which BIM would open up the era of big data for the construction industry.In addition, it has been defined as a management platform that could be applied to all stages of the building lifecycle, including planning, design, construction, post-operation, and renovation, with five main features, namely visibility, coordination, simulation, optimization, and mapability.
In 2016, with the continuous exploration and application of a new generation of internet technologies in the construction industry with big data, IoT, cloud computing, and other technologies, the concept of smart building has emerged, bringing better development prospects to the construction industry in China [34].The reconstruction opportunity to successfully build a smart control platform has been used to integrate IoT, cloud computing, big data, and mobile internet for the reconstruction project of Fengman Hydropower Station [40], which addresses the problem of engineering data sharing and collaboration, strengthens the control of the construction process, and improves the information on the management level of construction.In addition, in 2016, the Ministry of Housing and Construction of China organized the preparation of the Outline for the Development of Informatization in the Construction Industry from 2016 to 2020 [1], which clearly aims to enhance the combined application capability of BIM along with technologies such as cloud computing, big data, and IoT in the 13th Five-Year Plan period in China.
In 2017, as internet plus became China's national strategy [1] and the new engine of economic growth in a new normal, China's construction industry entered the construction information age.However, the adoption of the internet during this period in China's construction industry had just begun, with features such as long production cycles and large workloads severely limiting the information integrity and efficiency of the construction industry, and leading to increased costs and the inadequate use of social resources.As such, the Chinese construction sector urgently needed to be transformed with a new generation of information technology, such as the internet and big data [15].
In 2018, China's Central Economic Work Conference redefined infrastructure development, defining 5th Generation Mobile Communication Technology (5G), artificial intelligence, industrial internet, and IoT as China's new infrastructure development [46].Subsequently, the Chinese government's 2019 work report [47] included a section on enhancing the construction of the information infrastructure of the next generation.Accordingly, research related to construction informatization in China has been highly developed throughout 2017 to 2018.
In 2019, the Chinese government's work report indicated that the development of industrial internet platforms, the extension of intelligence plus, and the facilitation of the modernization and transformation of manufacturing industries are all crucial matters [48].Since then, artificial intelligence-related research has begun to emerge.Hence, the comprehensive implementation of artificial intelligence throughout the whole life cycle of civil engineering infrastructure planning, design, building, and maintenance would significantly impact the evolution of civil engineering science, technology, and engineering [49].
In 2020, China's Ministry of Housing and Urban-Rural Development and 13 other departments issued the "Guidance on Promoting the Synergistic Development of Smart Construction and Construction Industrialization" [50], which clearly proposed that by 2025, the policy system and industrial system for the synergistic development of smart construction and construction industrialization in China should be fundamentally established.By 2035, China's core competitiveness in construction could be world-leading and construction industrialization would be fully realized.The year 2020 was the first year of smart construction development in China.As a result, research on Chinese infrastructure increased dramatically between 2018 and 2020, with a particular focus on applying big data, the internet, artificial intelligence, and other technologies to promote the modernization and transformation of conventional infrastructure.Particularly popular topics are rail transportation and road tunnels.Therefore, under the combined influence of road network construction shifting to the west, the construction strength of ultra-long tunnels, large-section tunnels, and underwater tunnels has surged [51].
Since 2021, research related to smart construction and artificial intelligence have shown significant growth.

Keyword Timeline Analysis
A timeline map of BIM and BD research in China has been generated on the basis of cluster analysis through the CiteSpace visual analysis software, as shown in Figure 10.There are four clusters which are each tagged with keywords from the co-occurrence network, aligned with the appearing year of the keywords, and illustrate the evolution of each cluster's keywords.
In big data tagging clustering, BIM-and BD-related research first appeared in China in 2015, and then gradually transformed from theory to practice.In 2017, BIM and BD were first applied to the fields of health inspection [17] and intelligent management [20].An application mode of an intelligent supervision concept in the construction of water transport projects has been proposed with the help of the enhanced maturity in the field of information technology at the time, such as big data, sensor application, and internet plus, taking information intelligence technology as a means and the Specification for Construction Supervision of Water Transport Projects as a reference, to integrate all related responsible parties together through the information system platform to form a set of integrated solutions for the intelligent management of water transport project construction [20].In addition, a series of specific and implementable technical routes have been developed, such as the digital management of construction monitoring, intelligent monitoring based on environmental protection, high-precision and wide-scale information-based feedback construction, risk identification and monitoring and early warning, data mining, and analyses of monitoring data based on big data technology [17].In 2018, the implementation of BIM and BD in engineering project management in China has made greater progress, not only developing a set of construction cost application systems based on BIM cloud data by implementing the use of technology that involves BIM and cloud data [52], but also building an integrated model of a major engineering organization system based on a big data agent service [16].
Buildings 2023, 13, x FOR PEER REVIEW 13 of 32 Since 2021, research related to smart construction and artificial intelligence have shown significant growth.

Keyword Timeline Analysis
A timeline map of BIM and BD research in China has been generated on the basis of cluster analysis through the CiteSpace visual analysis software, as shown in Figure 10.There are four clusters which are each tagged with keywords from the co-occurrence network, aligned with the appearing year of the keywords, and illustrate the evolution of each cluster's keywords.In big data tagging clustering, BIM-and BD-related research first appeared in China in 2015, and then gradually transformed from theory to practice.In 2017, BIM and BD were first applied to the fields of health inspection [17] and intelligent management [20].An application mode of an intelligent supervision concept in the construction of water transport projects has been proposed with the help of the enhanced maturity in the field of information technology at the time, such as big data, sensor application, and internet plus, taking information intelligence technology as a means and the Specification for Construction Supervision of Water Transport Projects as a reference, to integrate all related responsible parties together through the information system platform to form a set of integrated solutions for the intelligent management of water transport project construction [20].In addition, a series of specific and implementable technical routes have been developed, such as the digital management of construction monitoring, intelligent monitoring based on environmental protection, high-precision and wide-scale information-based feedback construction, risk identification and monitoring and early warning, data mining, and analyses of monitoring data based on big data technology [17].In 2018, the implementation of BIM and BD in engineering project management in China has made greater progress, not only developing a set of construction cost application systems based on BIM cloud data by implementing the use of technology that involves BIM and cloud data [52], but also building an integrated model of a major engineering organization system based on a big data agent service [16].
In the Artificial Intelligence tagging cluster, artificial intelligence brings new opportunities for advancement in the field of civil engineering.The term digitalization appeared for the first time in China's civil engineering discipline in 2018, which attempts to use In the Artificial Intelligence tagging cluster, artificial intelligence brings new opportunities for advancement in the field of civil engineering.The term digitalization appeared for the first time in China's civil engineering discipline in 2018, which attempts to use intelligent means to drive the development of digital construction.Technologies such as deep learning and machine learning algorithms of artificial intelligence, computer vision, drones, three dimensional (3D) printing, BIM, virtual reality, and augmented reality are gradually being applied to civil engineering, profoundly transforming the development of civil engineering science, technology, and engineering in China, and advancing the innovation and application of smart construction technologies in China [49].From 2020 to 2022, research on smart construction reached a climax with nine studies related to smart construction, including a smart construction integrated management system [31], smart construction technology of a shield tunnel [22], the implementation of smart construction technology in the field of engineering cost management [10], smart construction technology of a highway [53], and smart construction technology of an underground station [32], which significantly accelerated the development of the field of intelligent construction in China.
In the IoT tagging cluster, with the continuous exploration and practice of a new generation of internet technologies with big data, IoT, and cloud computing in China's construction industry, the concept of smart building was born [34].In 2018, with the gradual progress of the new health care reform policy, a strong effort to build smart hospitals became the consensus of the community [38].Between the years 2020 and 2022, BIM and BD in China were playing an increasing role in traffic engineering and waste water treatment.Related studies include the digitization of road infrastructure [37], the smart management of expansion projects [39], and smart geotechnical engineering [30].
In informatization tagging clustering, the term digital tunneling appeared for the first time in China in 2017.The primary obstacle preventing the safe and efficient construction of tunnels is the complex and bad geological conditions; therefore, the first step towards achieving safe and efficient tunnel construction is to raise the standard of geological prediction and forecasting technology and its digitization [42].In 2019, China paid more attention to the field of research on data application.A model for the development of informationization in the survey and design industry in the internet plus and big data information era has been proposed, based on the analysis of the current situation as well as the issues surrounding survey production management informationization and survey professional development informationization, with reference to the industry characteristics of the informationalization and improvements in the technology of state-owned survey companies [44].From 2021 to 2022, the digital twin became a new trend in China's research in the field.The concept of the digital twin was originally proposed by Professor Grieves in 2003 at the University of Michigan's product lifecycle management course, which is defined as a three-dimensional model that includes a physical product, a virtual product, and the connection between the two [54].A general architecture and data integration model for a digital twin-based intelligent management platform has been generated for dam construction in a reaction to the deficiency of data correlation analysis and visualization to assist decision making in existing dam construction management systems [55].With the construction of a panoramic digital twin management system, additionally, the management and visualization of spatial data, water resources, water engineering, pollution data, management facilities, and the status of electromechanical equipment have been integrated within the scope of the Jiaodong Water Transfer Project, realizing the monitoring and management of water quality and quantity as well as water functional areas, and providing intuitive and effective support for intelligent watershed management [43].
Thus, the development of BIM and BD research in China can be divided into four phases in terms of the timeline: The start-up phase: the time period of 2015 to 2016 is the start-up phase of BIM and BD research in China.
The construction informatization phase: the time period of 2016 to 2017 is the construction informatization phase in China, with the rise of China's internet plus as a national strategy and the development of the internet and big data in China, in which the construction industry and the internet began to integrate, BIM and BD were really widely used in the field of construction engineering, and the Chinese construction industry opened the era of construction informatization.The main keywords of the related studies are informatization, internet plus, integrated application, and smart hospital.
The new infrastructure and BIM and BD application practice phase: the time period of 2018 to 2019 is the new infrastructure development phase in China, which is accompanied by the development of 5G, artificial intelligence, industrial internet, and IoT, as well as the increase of construction demand such as rail transit and highway tunnels.An abundance of research of highways, rails, tunnels, and bridges emerged, and the implementation of BIM in the management of projects was deepened.
The intelligent construction development phase: since 2020, China's BIM and BD research has entered the intelligent development phase, as China's industrial internet and artificial intelligence has continued to grow quickly, as well as the promotion of a series of policies, intelligent construction, and construction industrialization development in collaboration during this phase, in which a large number of intelligent construction-related studies have appeared.

The Literature Co-Citation Analysis
The literature-based Co-Citation Knowledge Map produced by CiteSpace can visualize the knowledge foundation and research frontiers of academic disciplines.The co-citation analysis was conducted on the reference documents of a total of 89 literature articles in the BIM and BD research field from the CNKI database.The total number of reference documents analyzed was 1256.
Figure 11 illustrates a visualization knowledge map generated from the data analysis.Every node in the map represents a piece of the literature that has been cited; the circles that surround the nodes indicate the amount of times that piece of the literature has been cited in various years; the size of the circles reflects the number of citations in each year; and the differences in color shades signify the different years [12].The literature with a co-citation frequency greater than three was considered to be the key literature, and Figure 11 displays a total of six of these pieces.
alize the knowledge foundation and research frontiers of academic disciplines.T citation analysis was conducted on the reference documents of a total of 89 literatur cles in the BIM and BD research field from the CNKI database.The total number of ence documents analyzed was 1256.
Figure 11 illustrates a visualization knowledge map generated from the data an Every node in the map represents a piece of the literature that has been cited; the c that surround the nodes indicate the amount of times that piece of the literature has cited in various years; the size of the circles reflects the number of citations in each and the differences in color shades signify the different years [12].The literature w co-citation frequency greater than three was considered to be the key literature, an ure 11 displays a total of six of these pieces.Moreover, Table 3 was obtained by summarizing and analyzing the abstracts and full texts of the six key literatures that were retrieved from CNKI.As can be seen, these key literatures are primarily concerned with the integration of infrastructure construction and maintenance [56], the application of big data in engineering project management [57], the application of AI in urban planning and design [58], the research and application of AI in civil engineering [49], the research and application of intelligent high-speed railway architecture [59], and the intelligent development and promotion of tunnel boring machines [60].Furthermore, the research topics of the citations have a substantial influence on the trajectory of BIM and BD research in China.In this paper, with the use of CiteSpace software, a cluster on the basis of the above co-citation analysis was conducted to obtain the co-citation clustering map, as shown in Figure 12, and it was found that the research of these literatures can be roughly classified into 10 categories, including Bridge Informatization, Road Construction, BIM, Big Data, Traffic Engineering, Cloud Computing, Virtual Reality, Engineering Management, and a City Transit System.The clustering topics of the citations basically present the history and evolution of the basic research on BIM and BD in China.A further timeline graph, as shown in Figure 13, was generated based on the co-citation cluster graph.According to the chronology, the foundational literature on BIM and BD research in China emerged in 2013, with a concentration on big data and cloud computing.These research topics include the dynamic control of rock explosion incubation processes [61], the research of soft soil underground engineering and deep excavation [62], and the research of automatic identification and warning of safety hazards in subway construction.A further timeline graph, as shown in Figure 13, was generated based on the cocitation cluster graph.According to the chronology, the foundational literature on BIM and BD research in China emerged in 2013, with a concentration on big data and cloud computing.These research topics include the dynamic control of rock explosion incubation processes [61], the research of soft soil underground engineering and deep excavation [62], and the research of automatic identification and warning of safety hazards in subway construction.A further timeline graph, as shown in Figure 13, was generated based on the co-citation cluster graph.According to the chronology, the foundational literature on BIM and BD research in China emerged in 2013, with a concentration on big data and cloud computing.These research topics include the dynamic control of rock explosion incubation processes [61], the research of soft soil underground engineering and deep excavation [62], and the research of automatic identification and warning of safety hazards in subway construction.In 2015, two influential papers on BIM and BD research in China were published, making a significant impact on the field.Ma et al. conducted an exhaustive search and analysis of relevant research in databases including the Web of Science [63], the Engineering Village, and the China National Knowledge Infrastructure.They presented an overview of the current application situation as well as future trends of big data technology in civil engineering.Yan analyzed the integrated application modes and value of BIM and IoT technology in construction site management, daily maintenance and asset management, emergency management, and simulation training, adopting into consideration the characteristics of BIM and IoT technology [64].With regards to standards and technical conditions, it also evaluated potential obstacles and problems associated with integration application.
In 2016, the Fengman Hydropower Station reconstruction project integrated numerous technologies, including BIM, virtual reality, IoT, cloud computing, big data, and mobile internet.It established a successful intelligent management platform with features including visualization, IoT integration, collaboration, and scientific control [40].The application of BIM in engineering management received widespread attention.
In 2017, Yang et al. constructed a three-dimensional structural framework for engineering project management by using big data [57].The researchers put forward a theoretical framework comprising of three distinct dimensions such as the time dimension, that encompasses each stage of the project lifecycle; the domain dimension, that encompasses the different management areas of the project; and the technique dimension, which encompasses the big data analysis approaches.The primary objective of this framework is to facilitate the development of big data technologies in engineering projects, with a focus on promoting research and its practical implementation.
In the year 2018, notable advancements were achieved in the field of virtual reality research due to the advancements in artificial intelligence.The advent of digital technology has had a dramatic impact on the awareness of the physical nature of the world and the societal structure [72].The study conducted by Batty M et al. [58] introduced an innovative approach that integrates the investigation of present-day phenomena with forward-thinking strategizing and development via the use of artificial intelligence technology.Wu et al. [73] presented real instances of intelligent data collection, intelligent configurations for city functions, and intelligent designs of city structures.They provided an analysis of the advanced mechanisms involved in artificial intelligence-supported city planning.
In 2020, significant breakthroughs were achieved in the research on the informatization of bridges.Yan et al. [65] introduced the Digital Image Correlation (DIC) technique for analyzing structural deformation video images.By utilizing the fast Fourier transformbased whole-pixel correlation algorithm and the inverse compositional Gaussian-Newton iterative sub-pixel matching algorithm, they successfully realized the rapid testing of the temporal displacement of multiple points in the structure.
As a result of the co-citation analysis, it can be seen that the articles with the highest citation frequency are primarily concentrated in the last ten years, and the main fields involved are the various applications of the integration of new technologies in various aspects of the construction field, particularly artificial intelligence, VR, and augmented reality.The rise of new technologies such as augmented reality, cloud computing, big data, and the Internet of Things has resulted in new advancements in building informatization, which is congruent with the conclusions of the analysis of Section 3.4.4.

Result of Microscopic Analysis
After the macro bibliometric analysis, a follow-up microscopic analysis of all the 89 core pieces of literature in the field has been conducted to analyze the main research themes and methods regarding BIM and BD in China.The research methods and themes have been categorized, as shown in Table 4, to demonstrate the present status of research development and future research trends in BIM and BD.
In the CiteSpace cluster analysis in Section 3.4.2,Group 0 'Big Data', Group 1 'Artificial Intelligence', Group 2 'IoT', and Group 3 'Informatization' are all associated with various fields derived from the combination of BIM and BD.According to the statistical analysis of the overall research themes in the literature, the implementations of BIM and BD in China are mainly focused on the intelligent construction stage and intelligent operation and maintenance stage relating to the domain of engineering construction, among which the bridge informatization is the top priority in the research of BIM and BD in China.Table 4 presents the research themes and research methods according to the categorization of the subject content, further demonstrating in depth the research process of the integration and development of BIM and BD in China.Among the 89 studies, there are 56 (63%) on the topic of Smart Construction, 27 (30%) on the topic of Intelligent Operation and Maintenance, and 6 (7%) on the topic of Bridge Informatization.In particular, the studies on the theme of smart construction are mainly related to the construction research on railway, tunnels, highways, and other infrastructure construction in China.The Intelligent Operation and Maintenance topic not only has been focused on the implementation of BIM and BD relating to the domain of operation and maintenance, but also on the protection of watersheds and river management in the process of operation and maintenance.With regard to the methodology of research, there are only a small number of studies that clearly describe the research methodology, and the main research methods are Empirical analysis [16], Questionnaire survey [74], Literature Research [24,75,76], Bibliometric methods [23,32,77], case studies [41,[78][79][80], and Literature reviews [10,38,53,81,82].These studies have greatly contributed to the development of BIM and BD research in China.

Smart Construction
Smart construction is a construction method that highly integrates information technology, automation, and intelligence with the engineering construction process, mainly including the intelligent management of construction sites, BIM, a digital twin, 3D printing, and intelligent robotics [23].With the constant development of technology and industrial techniques, Chinese society has gradually stepped into the digital and intelligent era.China has made great progress in intelligent construction, in which artificial intelligence and the digital economy are flourishing.At the same time, a higher degree of development has been made in the area of intelligent building via the combined use of big data and BIM.As shown in Table 4, in the field of BIM and BD research in China, studies on smart construction mainly focus on a number of transportation-related fields such as railways [87], roads [88], tunnels [19], and tracks [109], of which 29 studies demonstrate the use of smart construction in the field of transportation engineering.In the field of railway construction, operation, and maintenance, the rendering speed of China's multi-disciplinary integrated BIM design system for railways has been effectively improved through in-depth research on big data rendering technology in railway BIM design systems to avoid the problems of a sluggish system response and user interface stagnation [87].In terms of highway engineering, a "five-segment" categorization and coding architecture of highway engineering information has been developed in accordance with the ISO 12006-2 [129] standard, covering project, work point, component, location, and version, taking into account different needs such as construction management, measurement and payment, archive management, and big data utilization, which has been implemented into the real engineering construction management information system [88].Regarding tunnel construction, an innovative BIM-based information-based construction management solution has been used for a series of important and difficult factors that affect and restrict the efficient and safe construction of the tunnel, such as the high environmental protection requirements in the central section of the city, the high environmental risks of crossing complex geological strata, and the technical difficulties of the construction of the first single-hole double-line large-diameter shield in China [19].The integration of safety risk monitoring and tunnel construction information technology based on BIM and BD technology, has been proposed in the concept of "digital tunnel and intelligent tunnel" [42].Further, solutions on the concept of the intelligent management of tunnel construction have been suggested in view of the construction technology needs of various transportation fields [101].In the field of rail engineering, the scientific and intelligent development of urban rail transport requires the integration of BIM, Geographic Information System (GIS) software platforms, and data standards.This is the key to unlocking the potential of BIM, which is also an important support for the synergistic development of rail transportation and cities in the era of big data [75].Evidently, the development of smart construction is an essential research topic in the realm of construction in the field of transportation.
Moreover, the advantages of using intelligent construction in water engineering has been revealed in terms of engineering digitization [41] and engineering informatization [43].The actual Jiaodong water transfer project in the Shandong Province, China, has been used as a case study to analyze key technologies of information construction for water conservancy projects, providing successful management model experience for the subsequent development of intelligent construction in water conservancy projects [43].Further, China's domestic and foreign cases of the digital application of large-and medium-sized water conservancy and hydropower projects have been represented by means of case studies, analyzing the current development status and problems in terms of engineering design, construction, and operation management for future development trends [41].
Furthermore, there are 17 studies which have investigated the development of intelligent construction from different technical level perspectives such as architectural design, project management, and project costing, which include three technical-level studies to explore urban shield tunnels [22], underground stations [32], and intelligent geotechnical engineering [30].As technology and industrial techniques continue to evolve, China has gradually stepped into the digital and intelligent era, in which China's intelligent construction has made great progress.However, it is only by constantly promoting technological innovation and advancing the intelligent construction and digital building of infrastructure that Chinese smart cities can achieve digital transformation [22].

Smart Operations and Maintenance
Smart operation and maintenance refers to the maintenance approach of extracting value information from the massive operation and maintenance data for decision making.This approach is not only able to store and analyze massive data, but also provides assistance to operators in decision making.From the implementation point of view, intelligent operation and maintenance mainly involve steps such as intelligent monitoring, big data analysis, and applying maintenance decisions [130].
As indicated in Table 4, research on intelligent operation and maintenance in China's BIM and BD mainly involves intelligent control [40] and intelligent monitoring [20].Fengman Hydropower Station is the "mother of hydropower" in China, and is the first to implement visualization and digitalization technologies in an integrated intelligent control platform with a unified technical architecture, unified data management, and unified business and information standards, which breaks the situation of information silos and greatly improves China's management, operation, and maintenance level capability through the real-time monitoring of data and information and the intelligent decision making of businesses [40].In addition, with the growth of internet plus, big data, IoT, and other advanced technologies in China, the integration between traditional industries and internet technology has entered a period of fast growth.Intelligent monitoring effectively improves the efficiency of engineering operations, of which the implementation of an intelligent governance concept in the construction of water transport projects has been clarified [20].Questionnaires have been used to explore the study of operation and maintenance management design in the field of office intelligence [120].The integration of BIM and Virtual Reality (VR) technology has been implemented to achieve the transformation and upgrading of the coordination platform for assembly buildings [119].
Existing research shows that applying BIM technology during the building operation and maintenance phase has the potential to improve the exchange of information across all stages of the project, including design, construction, operation, and maintenance.Furthermore, it has been observed that the implementation of BIM technology can additionally ensure the accuracy and reliability of important data, consequently addressing the requirements of operation [120].

Bridge Informatization
Bridges are the key nodes and hubs of transportation engineering and are important safeguards for social safety and China's national economic development.With intelligence and information technologies continuing to advance, there are new opportunities for innovation in traditional bridge engineering in China.The creation of increasingly intelligent and high-precision bridge structures is bound to become the future direction of development [24].
Since information is the foundation of intelligence, information network systems should be established.The intelligence of bridges could not be achieved without the support of information.The research hotspots of bridge informatization and intelligent bridges in China are mainly focused on BIM plus technology, drones, inspection robots, and the deep learning of big data [29].The introduction of information technologies, such as the IoT and cloud computing, has significantly improved the monitoring efficiency of bridges [24], in which machine works will replace manual human workers more often in carrying out traditional bridge structure inspections and long-term maintenance monitoring work.Existing research shows that BIM technology can improve the level of refinement of positive bridge designs, process control in construction, and accuracy in management.In addition, the frontline technologies and important achievements in the field have been reviewed, summarizing the potential for this field's future in China as well as the present research hotspots [29].Further, a review of research progress on bridges and cloud computing in China has been conducted to make a deeper summary of the integrated management of bridge design, construction, and operation and maintenance [33], indicating that cloudbased BIM gives greater support to bridge informatization.

Literature Analysis of Web of Science Database in BIM and BD in China
In order to ensure the comprehensiveness of the literature related to the research, this paper used the topic keywords of BIM and Big Data and China to conduct a search in the core of the WoS database.Accordingly, a total of ten academic papers were collected.These papers are mainly concerned with the research topic of intelligent operation and maintenance and smart construction, as summarized in Section 3.5.This research includes the application of algorithm prediction and machine learning technology in intelligent railway construction [83,131], the application of blockchain technology and artificial intelligence [132,133], the combination of BIM in material budget and cost management [134], the application of BIM and Big Data Text Mining in concrete precast management platforms' effective application [135], the application of digital twins in hospital projects [136], and intelligent data retrieval and representation methods for cloud BIM applications based on natural language processing [137].
These studies highlight the significance of developing technologies and their application scenarios in the architecture, engineering, and construction industry [138,139], demonstrating the importance of these technologies in improving efficiency, reducing costs, and optimizing management, as shown in Table 5.
in the project planning and design stages, indicating that Chinese BIM and BD research has not yet been investigated across all of the project's life cycle stages.
The findings listed in Section 3.4's macro-bibliometric analysis suggest that the Chinese BIM and BD research is currently focused on the integrated research of big data, IoT, informatization, and artificial intelligence to optimize the management and decision-making work of engineering and project management, the development of intelligent construction technology, and a more intensive application in infrastructure construction fields such as rail transportation and heavy railways.Technologies including artificial intelligence, big data, the IoT, and information technology are not separate entities, but complement each other.Additionally, multi-technology integration to maximize the benefits of BIM is to fully use and truly promote data-based intelligent decision making [36].In the foreseeable future, the digital twin that deeply integrates extended reality technologies may become a new trend, through the deep integration of BIM modeling technology with GIS map data, the terrain, images, and realistic 3D models, and applied to realize the visual display of graphics and information, making the abstract data concrete and visualized [43].It could also integrate Virtual Reality (VR) and Augmented Reality (AR) technologies to serve the total process of the planning, design, construction, operation, and maintenance of engineering projects, and use the interaction between the virtual environment and real situation to achieve the intelligent control of on-site engineering projects [30].The integration of a digital twin with technologies such as the Internet of Things, edge computing, big data, AI, VR, and AR is the future development trend.As an enabling technology for digital twins, digital twin technology combines multiple data sources with AI technologies such as neural networks and machine learning to achieve faithful mapping, interactive feedback, and collaborative control of digital twin models and key data [140].The immersive experience provided by VR enhances the visualization and concretization effects of BIM models while also improving interactive functionality, offering a more immersive experience [141].By combining AR with BIM, virtual scenes can be seamlessly integrated into the real environment, allowing for a highly realistic reconstruction of the construction site.This integration enables the visualization of architectural details, thereby enhancing the level of intelligent construction in engineering projects [142].
Moreover, the findings of Table 2 in Section 3.4.1 indicate that the top three keywords in the high-frequency keywords for BIM and BD research in China from 2015 to 2022 are big data, IoT, and smart construction.In addition, keywords such as big data, IoT, artificial intelligence, cloud computing, and internet plus are frequently mentioned as indispensable technologies in the development of BIM informatization, while keywords such as heavyduty railway and rail transportation illustrate the main application areas of BIM and BD in China, and keywords such as smart construction, project management, and data platform reveal the main development directions of BIM and BD research in China.In terms of the timeline, the development of BIM and BD in China is driven by national policy guidelines such as the Outline for the Development of Informatization in the Construction Industry from 2016 to 2020 [1] and the Guidance on Promoting the Collaborative Development of Intelligent Construction and Building Industrialization [50].Responding to national policy guidelines and serving rail transportation, highway tunnels, and smart buildings, the degree of integration of technology research has increased, of which the field of BIM and BD in China has developed in the direction of smart construction and smart operation and maintenance.
Furthermore, the results of the microscopic analysis of Table 4 in Section 3.5 indicate that the implementation of BIM and BD in China is focused on the smart construction stage and intelligent operation and maintenance stage in engineering construction, of which the construction information of the bridge is a top priority.The research on intelligent construction mainly focuses on specific application research in railway, highway, tunnel, and rail in the field of transportation, and the research on intelligent operation and maintenance mainly involves intelligent monitoring and intelligent management design.The research on bridge informatization associates with BIM plus technology, drones, inspection robots, and the deep learning of big data.In addition, the research content mainly concerns fundamental and technical aspects, functional application, and engineering application and practice.From the perspective of research methods, the literature review and bibliometric method have been adopted in a certain proportion, indicating the Chinese BIM and BD research interests in conceptual analysis and status analysis.In general, the current application of BIM and BD in China focuses on a single stage, and investigating an integrated BIM management platform covering the whole project lifecycle stages will become a new trend for future research development.Further, cloud computing technology addresses the sharing and interaction of data, the IoT solves the collection of data, and artificial intelligence mainly enables the means to empower the wisdom of mechanical equipment in the practice process.In the future, the amalgamation of multiple technologies to enhance the worth of data will promote the development of smart construction in China.

Development and Challenges of BIM and BD Research in China
The results of the keyword clustering analysis in Section 3.4.2indicate that the unified implementation of cloud computing, big data, IoT, and BIM helps with collecting, storing, organizing, and mining massive engineering data in the process of engineering construction.Hence, each of these takes advantage of each other's strengths to achieve smart decision-making centered BIM [36].In addition, the outcomes of the keyword emergence study discussed in Section 3.4.1 suggest that in order to facilitate the reform and advancement of the construction industry, both the Chinese government and local governments have introduced relevant policies since 2016 that have developed from the initial stage of demonstration application and promotion guidance to the stage of comprehensive promotion and multi-policy integration development [143].BIM-based intelligent control [106], building operation and maintenance [120], intelligent supervision [20], and information management [39] applications substantially improve the level of industry information and project benefits.Further, the results of keyword timeline analysis in Section 3.4.3highlight that BD technology research is still in its early stages in China and that big data's lack of cognitive capacity is a significant element influencing the decision-making process.Thus, some studies posit that the dearth of study pertaining to BD poses a hindrance to its use into certain domains [14].Additionally, the difficulties in integrating data, sharing data, and mining data are the key issues that restrict the in-depth application of big data.The ability to handle and analyze the data contained inside BIM models is essential to the successful mutual integration of BIM technology with BD technologies [11].The BIM platform provides a big data computing and analysis platform for the construction field to support the access and integration of multi-source heterogeneous data, to transform and process the statistics, analysis, and mining of the data, deeply mining the hidden value of the data, and finally to visualize and display or share the processing results to form a complete data analysis process [18].The integration of big data technology and BIM enables not only the solving of problems such as collision and the cost control of installation projects, but also the penetration into the management of the whole life cycle of construction projects [81], which plays a great role in optimizing the order of the industry, and improving the efficiency of enterprises and the work efficiency of practitioners [21].
Furthermore, the findings of the investigation and analysis conducted with a microscopic scope in Section 3.5 show that the application of BIM and BD in China is more focused on smart applications in the smart construction stage and smart operation and maintenance stage, which means there is less exploration in the planning and design stage.Information technology is a trend in urban development and the use of BIM with other technologies to develop, operate, and maintain urban underground spaces is in line with this trend [144].During the design stage, BIM helps to address the exchange and transfer of information in design works, enhance the level and quality of designs, solve difficult design problems, and improve the efficiency of designs [145].Emerging technologies such as big data and artificial intelligence to assist in the design of civil engineering are currently in their infancy, but have shown a great promise.In addition, although BIM technology has great advantages, it still has limitations in its application due to its software system and various other reasons, and BIM technology in China has not yet reached the collaborative operation and integration across the whole project's lifecycle stages.Future research could emphasize the use of BIM and BD in the domains of urban planning and engineering design, and break through the application barriers between the various stages in terms of smart planning, design, construction, and operation and maintenance, meaning BIM and BD could be adopted in various aspects of China's smart city construction.

Conclusions
This paper relies on a bibliometric approach to metrically visualize core journal articles on BIM and BD in China from 2015 to 2022 in the CNKI database to discover the areas of high activity and future potential developments of the integration of BIM and BD research, in which the main contributions of this study are as follows: (1) In terms of the research method, this study is the first of its kind to employ a combination of macro quantitative analysis and micro qualitative methods to investigate an interdisciplinary research issue, namely the integration of BIM and BD in China.(2) In terms of research techniques, by using the CiteSpace software and the SATI statistical analysis tool for bibliographic quantitative analysis via keyword co-occurrence analysis, this paper is the first to reveal the current research status, hotspots, and future development trends in the integration of BIM and BD in China from 2015 to 2022.(3) In terms of research findings, the popular research keywords for BIM and BD in China since 2015 are mainly focused on BD, informatization, IoT, and rail transportation.By categorizing the main research keywords of BIM and BD in China, three fruitful research themes in BIM and BD research in China have been identified, including Smart Construction, Intelligent Operation, and Bridge Informatization.BIM and BD in China's smart construction are mainly applied to railway construction, tunnel construction, road construction, and water conservancy construction projects in China, which play a significant part in the overall promotion of the building of infrastructure in China.In the field of smart operation, BIM and BD mainly promote the interaction and sharing of information in the operation and maintenance stage of China's construction industry from digitization and visualization in order to enhance the management effectiveness of the construction operation and maintenance.In the field of bridge informatization, BIM and BD studies use BIM technology to improve the refinement level of bridge design in China and apply BIM plus technology combined with drones and inspection robots to significantly improve the monitoring efficiency of bridge construction in China.In general, this paper presents an overall result of the results of the macro and micro analysis on the integration of BIM and BD in China, discusses the current status and application areas, explores the hotspots and trends, and provides a reference for future studies in the domain in China as well as worldwide.
From 2015 to 2022, the quantity of academic publications pertaining to the integration of BIM and BD applications in China was on an overall upward trend.Big data, IoT, smart construction, artificial intelligence (AI), VR, AR, information technology, and cloud computing are keywords closely related to the topic.Smart construction technology with AI became a research hotspot in 2022.With the development of AI, there will be an "automatic AI scientist" and "automatic AI engineer" with the ability to create theories, theorems, and designs [49].In the future, the application of BD analytics and BIM will have significant implications.It will allow for a more comprehensive and accurate prediction of building performance, optimization of design, and improved efficiency in construction [137].Moreover, it will enhance resource utilization efficiency by integrating data from sources such as equipment sensors, maintenance records, and energy consumption [140].This integration will also improve the efficiency of building equipment maintenance and reduce energy waste [136].Furthermore, within the realm of construction engineering, the integration of big data technology into BIM will facilitate the analysis of building data in conjunction with geographic information, traffic data, and demographic data [132].This integration will lead to enhanced efficiency in building design and planning, as well as a reduction in construction safety risks [134].This paper presents the prospective future direction of construction engineering integration and information technology in China, and provides a reference for China's domestic and international research.However, this paper only used the core journal literature from CNKI as a sample for the study, which is a small sample size.Therefore, subsequent studies may consider using all the data within the CNKI journal repository.In addition, future research can adopt a multidisciplinary application mindset to explore the application mode of the integration of BIM and BD in multidisciplinary fields, from concept to practice, to investigate the deep integration of BIM and big data.

Figure 2 .
Figure 2. The number of articles on the theme of building information modeling (BIM) and big data (BD) in the China National Knowledge Infrastructure (CNKI) database since 2015 (generated by authors).

Figure 2 .
Figure 2. The number of articles on the theme of building information modeling (BIM) and big data (BD) in the China National Knowledge Infrastructure (CNKI) database since 2015 (generated by authors).

Figure 3 .
Figure 3. Disciplines of BIM and BD publications since 2015 in China via CNKI database (generated by authors).

Figure 4 .
Figure 4. BIM and BD publications in the top 10 journals since 2015 in China via CNKI database (generated by authors).Further, the quantity of publications is an essential measure of research, as shown in Figure 5.A time series analysis of the top 10 journals by publication year for the number of papers published, analyzed by the SATI (Statistical Analysis Toolkit for Informetrics) software, was conducted to show that the Construction Economy, Tunnel Construction, and China Civil Engineering Journals had publications in the field of BIM and BD research in the year 2018 and have maintained a steady number of journal publications.The Journal of Highways, Bulletin of Surveying and Mapping, and the China Journal of Highway and

Figure 3 .
Figure 3. Disciplines of BIM and BD publications since 2015 in China via CNKI database (generated by authors).

Figure 3 .
Figure 3. Disciplines of BIM and BD publications since 2015 in China via CNKI database (generated by authors).

Figure 4 .
Figure 4. BIM and BD publications in the top 10 journals since 2015 in China via CNKI database (generated by authors).Further, the quantity of publications is an essential measure of research, as shown in Figure 5.A time series analysis of the top 10 journals by publication year for the number of papers published, analyzed by the SATI (Statistical Analysis Toolkit for Informetrics) software, was conducted to show that the Construction Economy, Tunnel Construction, and China Civil Engineering Journals had publications in the field of BIM and BD research in the year 2018 and have maintained a steady number of journal publications.The Journal of Highways, Bulletin of Surveying and Mapping, and the China Journal of Highway and

Figure 4 .
Figure 4. BIM and BD publications in the top 10 journals since 2015 in China via CNKI database (generated by authors).Further, the quantity of publications is an essential measure of research, as shown in Figure 5.A time series analysis of the top 10 journals by publication year for the number of papers published, analyzed by the SATI (Statistical Analysis Toolkit for Informetrics) software, was conducted to show that the Construction Economy, Tunnel Construction, and China Civil Engineering Journals had publications in the field of BIM and BD research in the year 2018 and have maintained a steady number of journal publications.The Journal of Highways, Bulletin of Surveying and Mapping, and the China Journal of Highway and Transport published studies in the field in the year 2019, of which the Highway had the highest number of publications.

Figure 5 .
Figure 5.The number of BIM and BD publications in terms of topic since 2015 in China via CNKI database (generated by authors).

Figure 5 .
Figure 5.The number of BIM and BD publications in terms of topic since 2015 in China via CNKI database (generated by authors).
, no significant co-operation network has been formed among leading research institutions in the BIM and BD field in China.Key research institutions such as the China Academy of Railway Sciences Corporation Limited and Southwest Jiaotong University are independent research institutions in the field.Tongji University has formed a co-operative network with the University of Science and Technology Beijing, the University of Tennessee, and Virginia Tech.Shenzhen University has co-operative relations with the Huazhong University of Science and Technology and the China Railway Design Group Co., Ltd.The China Communications Highway Planning and Design Institute Co., Ltd., has formed a triangular co-operation network with the China Communications Highway Long Bridge Construction National Engineering Research Center Co., Ltd., and Guizhou Highway Development Co., LTD.Similarly, Beijing Jiaotong University has established a triangular co-operation network with the China Railway Economic Planning and Research Institute Co., Ltd., and the China Railway Engineering Design and Consulting Group Co., Ltd.Further, Tsinghua University is in a co-operative relationship with Zhejiang Sci-Tech University.It is evident that China's BIM and BD research fields are still in the early phases of integrated research and they have not yet formed a large area of research co-operation or a dominant co-operative team.

Figure 6 .
Figure 6.Co-operation map of BIM and BD research among the research institutions in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 6 .
Figure 6.Co-operation map of BIM and BD research among the research institutions in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 7 .
Figure 7. Keyword co-occurrence map of BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 7 .
Figure 7. Keyword co-occurrence map of BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).
, the clusters represent the top four research focuses in the field of BIM and BD research in China from 2015 to 2022, which are big data, artificial intelligence, IoT, and informatization.Buildings 2023, 13, x FOR PEER REVIEW 10 of 32

Figure 8 .
Figure 8. Keyword clustering map of BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 8 .
Figure 8. Keyword clustering map of BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 9 .
Figure 9.The top 14 keywords with the strongest citation bursts in BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 9 .
Figure 9.The top 14 keywords with the strongest citation bursts in BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 10 .
Figure 10.Timeline map of BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Figure 10 .
Figure 10.Timeline map of BIM and BD research in China since 2015 from CNKI database via CiteSpace software (generated by authors).

Buildings 2023 , 32 Figure 12 .
Figure 12.Co-citation cluster map of BIM and BD research in China (generated by authors).

Figure 13 .
Figure 13.Co-citation timeline map of BIM and BD research in China (generated by authors) [36,40,57,58,63-71].In 2015, two influential papers on BIM and BD research in China were published, making a significant impact on the field.Ma et al. conducted an exhaustive search and

Figure 12 .
Figure 12.Co-citation cluster map of BIM and BD research in China (generated by authors).

Buildings 2023 , 32 Figure 12 .
Figure 12.Co-citation cluster map of BIM and BD research in China (generated by authors).

Figure 13 .
Figure 13.Co-citation timeline map of BIM and BD research in China (generated by authors) [36,40,57,58,63-71].In 2015, two influential papers on BIM and BD research in China were published, making a significant impact on the field.Ma et al. conducted an exhaustive search and

Table 1 .
Statistics of publications of BIM and BD from research institutions in China since 2015 (generated by authors).

Table 3 .
The key literature co-cited in BIM and BD research in China (generated by authors).

Table 4 .
Research themes on BIM and BD research in China since 2015 from CNKI database (generated by authors).