PRELIMINARY CHECKLIST PROPOSAL FOR ENHANCING BIM- BASED CONSTRUCTION PROJECT CONTRACTS

In multi-participant BIM-based construction projects (BbCP), the organization of inter-stakeholder relationships has become challenging. The emerging BIM roles and responsibilities that are not clearly defined as a standard, complicate this process further. Legal regulations and contracts prepared according to traditional construction methods are insufficient to identify these new and complex relationships. This uncertainty hinders the spread of BIM-integrated projects, causing stakeholders to have legal concerns about BIM-based projects. Within the scope of this research, the legal concerns related with BIM-based projects and critical points to be considered in the contract preparation phase were determined through literature review, case law research, first and second stage interviews and a questionnaire survey. 25 main and 32 sub-critical points were identified and recommended to be considered in the contract phase were categorized under 9 headings (i.e., administrative decisions, analysis, legal issues, allocation of risks and responsibilities, intellectual property rights (IPR), information management, interoperability, data security and the operation phase). As an outcome, this paper proposes a preliminary checklist template that can be used as an input to the contract phase of BbCP. With the support of checklist, measures can be taken at the contract stage for potential legal problems that may occur in the project life-cycle. The checklist can serve as a starting point for legislators and regulators to ensure the compatibility of traditional construction contracts with new technologies. Finally, addressing legal issues in BbCP can alleviate stakeholders’ concerns and lead to the spread of BbCP in the construction industry.


INTRODUCTION
CI (construction industry) is one of the essential pillars of the economies thanks to its own and secondary industries. The CI is, however, also one of the most difficult and challenging industries to manage mainly due to its multi-disciplinary complexity and uniqueness as well as changes in building materials and construction methods. To overcome this managerial challenge, BIM offers several advantages: improved information management, interoperability potential and integrated supply chain (BSI, 2015a), effective and efficient management of tasks (Liu et al., 2017), communication and coordination improvement (Bryde et al., 2013), and reduction in delays and conflicts (Ghaffarianhoseini et al., 2017). For example, 3D and 4D models prepared in BbCP (BIM-based construction project) can be integrated to various extended reality technologies to ensure that all stakeholders are included in the project from the first stage and that possible problems are detected early (Alizadehsalehi et al., 2019). Furthermore, conflicts which can arise especially in large and complex projects can be resolved through simulations . Moreover, communication between the design team and the owner can be enhanced by making more understandable architectural presentations with the virtual reality model (Khalili, 2021). Consequently, management of large-scale digital data has become important in this integration process (Alizadehsalehi et al., 2020).
As BIM is becoming widespread in the CI, the project processes (e.g., design, procurement, construction and operation) have started to change (Ashworth et al., 2019). Collaborative environment offered by BIM, information management has gained more value as importance of communication and coordination between stakeholders has been increased. Although BIM has several advantages, BbCP involve various risks e.g., managerial (Perrier et al., 2020), technical, legal, financial, environmental risks (Chien et al., 2014). In order to cope with these risks, key stakeholders of the project (e.g., the project owner, design team, construction team) need to work together in the preparation of the BIM contract at the contracting stage (Dougherty, 2015). Most of the standard contracts and protocols that can be applied to BbCP are created as an addendum to the master contract and they cannot cover all risks (Chong et al., 2017). Moreover, since modern legal systems are typically constructed based on conventional construction techniques, they concentrate on individual rights and responsibilities of the stakeholders (Pandey et al., 2016). In contrast, as participants need to work together in the collaborative environment of BIM to get benefit from BIM, existing legislation and regulations lack arrangements for integrated design and for regulating cooperation between stakeholders (Azhar, 2011).
Elimination and minimization of disagreements is essential for the efficient and effective implementation of the project. Increase in the number and diversity of stakeholders and digital data reveals various risks in BbCP (Liu et al., 2017). The risks that may occur during the project process can be reduced/prevented through the collaborative and communication-supported structure of BIM (Ghaffarianhoseini et al., 2017). Furthermore, these risks may turn into disputes due to some deficiencies in the contracting phase (Dougherty, 2015). The main issues that can pose these risks are: identifying BIM roles and stakeholders responsible for them (Arensman and Ozbek, 2012;Bosch-Sijtsema et al., 2017;Ussing et al., 2016); IPR (intellectual property rights) in the common information platform (Arshad et al., 2019;Manderson et al., 2015;Solihin and Eastman, 2015), software compatibility (Bynum et al. 2013;McAdam, 2010;Succar, 2010); data security (Chien et al., 2014;Dougherty, 2015;Eschenbruch and Bodden, 2018); and digital data storage (Bakhary et al. 2015;Lai et al., 2019). Preparation of a clear and detailed contract can minimize disputes in the project life-cycle (Sardroud et al., 2018). This paper focuses on contract aspect of the BbCP and the main legal concerns related with the integration of BbCP's requirements and needs into the contract. With this aim, international guidelines, standard contracts and protocols were examined, case law research was conducted, first and second stage interviews and an onlinequestionnaire survey were performed. As a result, critical points to be considered in BIM-based contracts were determined and a preliminary checklist template was proposed to support the contract preparation phase of BbCP.

BIM-based CPM process
In complex construction projects with multi-stakeholders, planning the interaction of stakeholders throughout the process can reduce risk of conflicts and disputes. Main headings, scopes and topics highlighted in the examined guidelines have been executively summarized in the Table 1.

BIM-based CPM stakeholders and teams
A collaborative environment including all supply chain participants is needed to get benefit from BIM. Ensuring that all expertise and knowledge of stakeholders are shared with each other through effective stakeholder management is important for the success in project management process (Srinivasan and Dhivya, 2020). With the spread of BIM in the CI, new roles and responsibilities are evolved (Uhm et al., 2017). Although according to a recent study 35 different BIM related job titles have emerged (Uhm et al., 2017), there is no generally accepted definition of the duties and responsibilities of these roles (Bosch-Sijtsema et al., 2019).

FIG. 2:
Definitions and hierarchy scheme of BIM roles.

BIM-based CPM documents
Integration of BIM into the traditional construction process can be facilitated through the documents regulating this process. BIM Execution Plan (BEP), which contributes to the integration process through determination of the BIM requirements and goals at all project stages, is one of the most important documents (Abdirad, 2015). Although BEP content is not well defined as a standard in the literature, it should fundamentally include details on the following topics (Eschenbruch and Bodden, 2018): data production, level of detail, milestones of the process, responsible groups and coordination actors. Although the names vary, all investigated guidelines mention the BEP document. All guidelines state the importance of creating BEP in the early stages of the project for effective BIM integration. Some guides (COBIM, 2012;SBIM, 2013;NBIM, 2013;BBIM, 2015;NATSPEC, 2016;NBGO, 2017;BSI, 2018a) indicate that BEP should be seen as a dynamic document and updated through project phases. Along with the BIM Implementation Plan, various documents according to the stages of the project are highlighted (COBIM, 2012;NBIM, 2013;BSI, 2015a;NATSPEC, 2016;NBGO, 2017;PSUBIM, 2019). These documents can be classified under 3 main headings under the organizational, asset and project-based levels (BSI, 2018b) as follows: Organizational Level: BSI ISO1 (2018b) emphasizes OIR (Organizational Information Requirements) and PIR (Project Information Requirements) respectively to determine the organization's high-level strategic objectives, portfolio planning and regulatory policies as well as to measure and monitor decisions on a project specific basis. PSUBIM (2019) recommends publishing a BIM Mission Statement document that specifies the importance of BIM to the company, and which details its usage for future corporate decisions.
Asset Level: BSI ISO1 (2018b) emphasizes the AIR (Asset Information Requirements), in which managerial and commercial decisions about the asset as well as production methods and procedures are determined. Furthermore, BSI ISO1 (2018b) emphasizes the AIM (Asset Information Model), where project-based responses to these asset decisions are specified. Moreover, while NBGO (2017) states that the expectations of the project stakeholders from the operation phase should be specified, NBIM (2013) recommends alternative investment evaluations to be made considering the building life-cycle.
Project Level: While the NBGO (2017) points out that the client must specify the design and facility approaches regarding the owner's demands, NATSPEC (2016) specifies a document called Project BIM Brief, which defines the needs of the employer during the project process. Similarly, BSI ISO1 (2018a) recommends the EIR (Exchange Information Requirements), which defines the information that the client must fulfil at the project close-out phase as well as the PIM (Project Information Model), which defines the information requirements and procedures in the project delivery phase. Differently, PSUBIM (2019) recommends the BIM Use Selection Worksheet, which regulates when each stakeholders will undertake BIM tasks throughout the process and which specifies their BIM competency levels.
Integration of BIM into the contract is challenging as it contains large amount of information directly used by stakeholders. Standard contracts and protocols have been established to overcome this challenge (Abdirad, 2015). The actual use of these documents, however, has not yet become widespread in the CI (Al-Shammari, 2014). Although many researchers (Arensman and Ozbek, 2012;Ussing et al., 2016) indicate that international standards should be established to prevent legal problems that may arise in BIM integration, they also agree that country specific differences should be considered.  The employer should establish a completed protocol for defining and sharing of responsibilities as well as ensure that the protocol is integrated into all project agreements (CIC, 2018;JCT, 2016).
Participants are responsible for their contribution to the model, the data generated from their contribution, and the data generated by contractually lower tiers of the participants (CDOC, 2015).

IPR
The written consent of the data-generating party is required for the usage and modification of data to ensure the protection of IPR (AIA, 2013;CIC, 2018).
Shared data can only be used by the recipient party for the relevant construction work (AIA, 2013;CDOC, 2015;CIC, 2018).

Information management
The participants should establish a protocol to manage the centralized electronic documents management system AIA (2013).
The models expected from stakeholders through project stages should be described in the protocol according to the project stages (JCT, 2016;CIOB, 2013).
The participant cannot be held responsible for damages resulting from unauthorized data use and modification (CDOC, 2015;CIC, 2018).
The software and formats to be used in the process should be determined to prevent interoperability problems (CIC, 2018;CIOB, 2013).
All 2D drawings of the project should be extracted from the 3D common model (CDOC, 2015).
Data security and storage Procedures should be established for uploading, viewing, modifying, backing up and archiving information on the common platform for IPR and data security (AIA, 2013; CDOC, 2015; CIOB, 2013).

Contractual Aspects of the BIM-based CPM
There are several legal concerns in the integration of BIM-based projects into contracts (Dougherty, 2015). As contractual arrangements covering BIM goals and outcomes have been repeatedly identified as a challenge locally and internationally (Kuiper and Holzer, 2013), effective contract management with written provisions is vital for regulating legal concerns and implementing necessary procedures (Fan et al., 2019). It is necessary to define new services, responsibilities and legal issues arising from changes in the construction planning through BIM integration. Nevertheless, due to the lack of experience, there is no common strategy for BIM contracts (Eschenbruch and Bodden, 2018).
BIM requires a number of stakeholders to work collaboratively to transform data into a 3D virtual model (Papadonikolaki et al., 2019). Since traditional construction contracts are mostly bipartite documents, various legal problems may arise during this collaboration (SBEnrc The Sustainable Built Environment National Research Centre, 2017). The main causes of legal concerns and disputes about BIM are: • Ownership of the model, risk allocation, IPR and interoperability (Jo et al., 2018).
• Responsibility of the used data, responsibility of quantities, clash detection, professional reliability and third parties related to BIM (Ussing et al., 2016). • Unclassified and/or non-prioritized documents (Charehzehi et al., 2017).

Critical aspects of contract management in the BIM-based CPM
High number of stakeholders and data in BIM integration reveals various risks (Liu et al., 2017). Although collaborative nature of BIM reduces conflicts (Ghaffarianhoseini et al., 2017), some deficiencies at the contracting stage can lead to various disputes (Dougherty, 2015). Causes of conflicts that occur throughout the life-cycle of BbCP can be grouped under four main headings (Ashcraft, 2008;Arensman and Ozbek, 2012;Kuiper and Holzer, 2013;Dougherty, 2015;Ashworth et al., 2019;Huzaimi and Fathi, 2019): allocation of risks and responsibilities, IPR, interoperability, data security and documentation. They can be described as follows: Allocation of risks and responsibilities: The modern legal structure is based on the distinct concept of obligations (Arensman and Ozbek, 2012), while the collaborative and integrated system of BIM mixes levels of responsibility between different stakeholders (Azhar, 2011). Additionally, unlike the signature and stamp system in paper-based documentation, it is more difficult to identify responsible persons in the integrated model (Schapke et al., 2018). Consequently, the main contract should be supported by additional forms and protocols to protect the stakeholders involved in the BIM system (Azhar, 2011;Hsu et al., 2015).
IPR: The collaborative environment entails the risk of exposing and sharing data valuable to stakeholders (Hsu et al., 2015;Solihin and Eastman, 2015). Therefore, contractual status and ownership rights of the information generated and tools used in the project should be determined (McAdam, 2010;Kuiper and Holzer, 2013;Hsu et al., 2015).
Interoperability: Throughout the interactive and dynamic project process, the 3D common model must be on a controllable platform (Lai et al., 2019). Moreover, a contractually binding protocol regarding the production, exchange, share, approval, publication and certification of data in the project process should be established (Eastman et al., 2010;Siemens, 2017;Schapke et al., 2018).
Data security and documentation: Main problems of digital information transformation are ownership and data security issues of BIM deliverables (Solihin and Eastman, 2015). Additionally, accessibility of electronic data by all stakeholders, raises concerns about unauthorized online access and ownership violations (Chien et al., 2014). For this reason, as digital information must be protected against loss, corruption, and theft (Olatunji, 2011), data need to be gradually authorized based on data's intended use and stakeholders' responsibilities (Eschenbruch and Bodden, 2018;Schapke et al., 2018).

Critical points of BIM-based CPM
Within the scope of this paper, international standard contracts and protocols, and international guidelines were analysed to determine the critical points of BIM-based CPM. In total, 6 standard contracts and protocols, 13 guidelines and 36 articles were examined. In these examined articles and documents, there are imperatives, recommendations and warnings for the critical points. As a result of this examination, 49 critical points of BIMbased CPM have been identified. These critical points are shown in the Table 3 where "dark grey cell" indicates documents that strongly mention the critical points whereas "light grey cell" indicates documents that weakly mention the critical points.

RESEARCH METHODS
This paper aims to develop a proposal for a preliminary checklist template that can be considered as a potential input to the contracting phase of these projects so that the contract preparation phase of BbCP can be improved.
Research flowchart is provided in Fig. 2. The objectives determined in accordance with the aim are as follows: • To review the BIM guidelines, standard contracts and protocols.
• To determine the critical aspects and issues to be considered in the BIM-based construction contracts.
• To propose a preliminary checklist template which can be considered as a potential input in the contract preparation phase of the BbCP.

Case Laws Research
Within the scope of the study, a litigation awards and case laws research was conducted through international (Lexisnexis.com) database to investigate the causes of BIM-related disputes that arise in BbCP. Among the search results, the ones originating from the BIM and BIM processes were examined.

First Stage Interviews
First stage interviews were conducted with 5 professionals who actively use and have experience in BIM technology. Participants' information is provided in the Table 4.

Online Questionnaire Survey
Following the interview, an online questionnaire (following the pilot study conducted to 10 professionals) was conducted via LinkedIn and e-mail to a sample of professionals with BIM-related job titles actively working in the CI. The online questionnaire, which was kept on for 6 months. In total 69 people filled in the questionnaire.

Second Stage Interviews
In order to further improve and verify the preliminary checklist template proposal, second stage interviews were conducted with 10 professionals who are experts in BIM. Professionals evaluated the created checklist in terms of design, clarity and content. Participants' information is provided in the Table 5.

Data Obtained Through Litigation Awards and Case Law Research
As a result of the research in the Lexis-Nexis database, case laws containing BIM-related disputes have been found in 3 out of 13 countries: United States, United Kingdom and Canada. Considering international case laws and literature (Ashcraft, 2008;Arensman and Ozbek, 2012;Kuiper and Holzer, 2013;Dougherty, 2015;Ashworth et al., 2019;Huzaimi and Fathi, 2019), it is seen that the main reasons for the disputes in BbCP are contractual problems. To summarize, dispute causes can be categorized under the following four main headings: allocation of risks and responsibilities; ownership and usage of right of the model and data produced; interoperability problems; and data security and documentation.
Comparison of the cases found by case law research with the critical points of BIM-based CPM (Table 3) according to their core terms is shown in Table 6 where the "grey coded cell" indicates the critical points causing disputes in the cases.

Data Obtained Through Interviews and Questionnaire Survey
Following the case law research, first stage interviews and questionnaire survey was conducted with professionals within the scope of field research. In the first stage interviews, the interviewees emphasized mainly the importance of: the IPR protection, training of suppliers on BIM and updating of the legal regulations in accordance with BIM. Table 7 summarizes the critical points emphasised in these interviews.
The majority of the participants in the questionnaire survey were architects (63%) and civil engineers (21%). The project roles of the participants are as follows: BIM manager (40%), BIM coordinator (13%), BIM disciplinary manager (10%) and BIM engineer (9%). The majority of participants have less than 10 years of BIM professional experience. 67% have 2-7 years of BIM professional experience. The mean values of the responses given by the participants to the effect of BIM on the performance of various issues are shown in chart A in Fig. 3. The mean values of answers given by participants to appropriateness of BIM integration to the project types are provided in chart B in Fig. 3.

FIG. 3: The performance effectiveness (Chart A) and the appropriateness (Chart B) of BIM integration.
Results obtained through the online questionnaire survey revealed that the participants emphasized the following topics: IPR should be stated in the contract; BIM requirements, purpose and responsibilities of the owner should be defined; a data security protocol should be established; and LOD levels should be defined as standard and specified according to the project stages. Table 7 further summarizes the critical points supported by the questionnaire survey participants.
The preliminary checklist template proposal, which was created based on the literature review, case law research, first stage interview and questionnaire, was verified with second stage interviews performed with the participation of 10 professionals having BIM expertise and experience. All interviewees stated that the suggested checklist was sufficient and useful and that all identified critical points were important. Furthermore, they have specifically emphasized the points specified in Table 7.
IPR: The most emphasized issues in the literature (Arensman and Ozbek, 2012;Manderson et al., 2015;Solihin and Eastman, 2015;Arshad et al., 2019) and under the subheadings 4.1 and 4.2 of this paper, are: the protocol for information; information confidentiality; copyright of the data produced and the authority sharing. Therefore, definition regarding the IPR should be included in the contract, and access to the common platform should be authorized (Manderson et al., 2015;Solihin and Eastman, 2015). Moreover, before the generated information is shared, a "term of usage letter" must be signed by the receiving party regarding ownership and user rights (CANBIM, 2012;AIA, 2013;CIC, 2018;Eschenbruch and Bodden, 2018).

PRACTICAL IMPLICATION
Preliminary checklist template categorized under 9 headings is provided in the Table 8. The roots of each item has been provided referring to the relevant literature, standards and documents as well as to the field studies. Accordingly, in Table 8 QS stands for questionnaire survey, IS1 for first stage interview, IS2 for the second stage interview, CLR for case law research. The checklist consists of 25 main 32 sub-critical points as well as their descriptions and highlights. The checklist was created in line with the findings and critical points obtained from the literature review (Table 3) and field research (Table 7). Considering the proposed checklist as a support document during the contract preparation phase of BbCP can contribute to reduce the potential disputes that may arise. Furthermore, stakeholders' legal concerns arising from the BIM integration can be alleviated through integration of all stakeholders into the contract preparation phase. This paper and the proposed checklist can be considered as an input to the establishment of legal standards for BIM-based construction projects. They can be beneficial to academic researches, to academics and researchers in this field. Furthermore, the identified 9 main categories of the preliminary checklist template proposal and their relation to the Project Management Institution (PMI, 2017) knowledge areas and BSI PAS 1 (BSI, 2015a) project stages are provided in Fig. 5.

Critical points of administrative decisions.
o Organization-related Decisions (COBIM, 2012;NBIM, 2013;BSI, 2018a;Ashworth et al., 2019;PSUBIM, 2019) Define the high-level strategic goals of the organization and includes the strategic decisions of the organization, portfolio planning, regulatory tasks, and policies.
Prepare a statement for the organization's future BIM-related organizational decisions, and describe why BIM is important to the organisation and how to use it.
Stakeholders working with complex and large projects should determine their organizational decisions. IS2 If the organization needs to be departmentalized for BIM applications, determine its procedures. IS2 Set your own BIM specifications on why you prefer BIM and how to implement it. IS2 Determine whether BIM process management will be done by the company or outsourced to third parties.  Measure and monitor that organizational decisions are supported in a particular project.

2.
Critical points of analysis.

2019) CLR, IS, QS
Identify the information that should be confidential by stakeholders such as design works, rates and prices that produced or used throughout the project.

CLR, IS, QS
Identify ownership rights of the common BIM model during project process and for operation and maintenance stage.
Ownership of the model can switch between the stakeholders depending on the project stages. IS2
The information protocol should include an information map that contains all the information produced and shared according to the stages of the project. To avoid differences between the model and construction implementations, determine the procedures required to extract all 2D drawings that will be used during the construction application from the 3D model. Set change order procedures to reduce time and cost related issues that will occur due to any changes in the project.
The software and platform to be used for the change order must also be specified. IS2 Change order transmittals in the project need to be archived to ensure that stakeholders are noticed the changes and take responsibility. IS2
Databases used internally and among stakeholders should be organized in different ways. Use data insurance to cover financial losses that will arise from any problems with data security.
9. Critical points of operation phase. Identify the processes of converting construction applications to as-built models and those responsible for control of this process.
The layouts should be updated regularly during the construction phase of the project. IS2 Provide authorized sharing of data in the common model to prevent data from being shared to unauthorized 3rd parties. o

CONCLUSION
This paper proposed a preliminary checklist template that can be considered as a potential input to the contracting phase of these projects so that the contract preparation phase of BbCP can be improved. With this aim, existing standard contracts, protocols and guidelines were examined and compared to each other. Furthermore, legal disputes in BbCP were investigated through litigation awards and case law research in international databases. Subsequently, first stage interviews and questionnaire surveys were conducted with BIM professionals. Based on the findings obtained through literature review, litigation awards and case law research, first stage interviews and questionnaire survey, the proposed checklist template has been created. Lastly, the proposed checklist template was verified through the second stage interviews. The proposed checklist template consists of 25 main 32 subcritical points.
Future studies on the legal issues of BbCP are recommended to focus on electronic contracts, where the BIM model can be part of the contract. In this way, the common model, which is one of the most important advantages of BIM, becomes legally binding among stakeholders.
In conclusion, the proposed preliminary checklist template can be used as an input to be considered for supporting the contract preparation phase of BbCP considering project-specific requirements and limitations. The proposed template can be useful to reduce legal concerns of stakeholders in the CI arising from BIM integration and to support the spread of BIM in the CI. With the development of construction technologies, the proposed preliminary checklist template can be updated or further developed with the experience and expertise gained from existing and future BbCP. Finally, the proposed preliminary checklist can be useful for BIM-based projects stakeholders as well as for lawmakers and public institutions dealing with legislation related to construction practices.