*4.5. Prototype Validation with a Virtual Business Scenario*

The prototype was comprehensively evaluated to ensure accurate execution of the smart contract using a virtual business scenario that involves external validation. The attributes of the virtual business scenario were set to conduct the test run. A building project was considered as a project type, and cladding attributes, as discussed in Section 3, were considered the CSC element to execute the smart contract. The role of the external entity (supplier) was performed by the researcher, while a participant organization performed the role of the main contractor. It was ensured that the information delivery system used by the participant organization is configured to work in accordance with the workflows for the CDE that are outlined in "*ISO-19650 Part 1, Section 12*", and the deliverables for the "BIM maturity Level 2" were based on the "*PAS 1192-2-2013*" standard. Table 1 illustrates the protocol for the virtual business scenario.


**Table 1.** Protocol for the virtual business scenario.

*Data Collection:* The prototype developed, as discussed in Section 4.4, was used to validate the integration of BIM and blockchain. Subsequently, the actors invoked and queried to test the system. The virtual business scenario concluded with a structured interview to complete the evaluation of the prototype.

*Data Analysis:* The test case scenario was used and the results of the test run were tabulated in the form of a checklist. This was performed to confirm that the prototype fulfills all of the system criteria and provides a software prototype for the integration of BIM and blockchain, as illustrated in Table 2.


**Table 2.** A virtual business scenario test case and its results.


**Table 2.** *Cont.*

There was consensus from the Participant Organization that the software prototype ensures the reliability of supply chain data delivery by enforcing the supply chain stakeholders to hand over on-chain data delivery. Further, the *Participant Organization* acknowledged that the software prototype for the integration of BIM and blockchain paves the way for the progression of the 3D BIM model toward the *digital engineering framework* [93] by enabling "machine-readable data" in the form of a reliably structured dataset. The *Participant Organization* acknowledged that there is a benefit in centrally integrating the on-chain supply chain data delivery utilizing the URL (XML format) because it assures that the software prototype delivers a vendor-agnostic solution that is compatible with several BIM vendor's software packages. The test run concluded with the recommendations to adopt the software prototype solution; the delivery partner should submit all project deliverables as structured datasets; thus, it should be contractually bound and represented as part of the Professional Services Agreement (PSA). The BIM execution plan needs to include the implementation costs and time. The software prototype is a new technological solution and the hardware requirements of blockchain are very expensive.

#### **5. Discussion**

Transparency, traceability, and a lack of supply chain data are some of the deficiencies of BIM use. Blockchain may alleviate the shortcomings of BIM by providing transparency and accountability and by ensuring ownership through smart contracts. However, its adoption is contingent on the data source, where BIM may play a significant role when paired with blockchain to provide verifiable data for supply chain operations [27,67]. By not restricting BIM to isolated electronic files, the prototype proposed in this study exploits blockchain's potential for value transfer toward a reliable ecosystem of interconnected databases. In addition, it facilitates machine-readable data in the form of uniformly formatted databases, opening the way for the progression of BIM toward digital engineering. The results of the test run validated the technical viability of the BIM single source of truth prototype using blockchain to ensure the delivery of trustworthy supply chain data in

blockchain that is centrally tied to BIM. As it links and stores on-chain supply chain data delivery through a URL, the system prototype offers a vendor-agnostic solution that is suitable for a variety of BIM software applications. The URL-XML format ensures semantic consistency across all disciplines of a project. The participating organization noted that the system prototype ensures a constant and predictable dataset of on-chain supply chain data delivery by using a logical and familiar navigation and use interface. The deployment of the system prototype for the virtual company scenario proved that businesses are keen to commercialize this solution not only to ensure consistent digital output but also to maintain a competitive advantage. The scalability of the suggested method was not, however, explored in this study. The development of the BIM single source of truth prototype utilizing blockchain technology will pave the way for the BIM handover model to enable the definition of the digital twin, as it has received significant attention as an emerging technology and is now regarded as a crucial component of Industry 4.0 [94]. The trust, which is the main quality of this prototype, will improve the BIM data quality and ensure its reliability for operation and facilities management, which was also introduced by the Centre for Digital Built Britain as one of the Gemini principles pillars placed on the digital twins for being a single source of information for operation and facilities management [33]. However, as the digital twin model supports the future vision of smart cities, the remaining question is, what about the sustainability position of this prototype? This paper does not study the sustainability impact of blockchain; however, this prototype is considered an industrial application (Blockchain 3.0) that operates without miners through the help of nodes, unlike the cryptocurrencies, such as Bitcoin (Blockchain 1.0) and smart contracts and financial applications, such as Ethereum (Blockchain 2.0) [95].

Despite the significance of this paper's results, it is important to acknowledge a few limitations. The system prototype does not account for variations that may result from different procurement procedures, in which the role of each stakeholder in the logical system may be modified. In order for the integration of BIM and blockchain to be really effective, however, individuals and organizations must rethink their traditional procurement practices and boost their investment in innovation. Future research could examine the relationship between the various procurement systems (Public-Private Partnership, Alliancing/Integrated Project Delivery, Design Bid Build, Partnering, Traditional, Management or Early Contractor Engagement, etc.), and the proposed method for the integration of BIM and blockchain. Therefore, the system prototype should emphasize the use of the "Generalized Adaptive Framework" (GAF) to automate the code verification processes for routing the data that must be deposited in the blockchain system. This may need the development of a computable representation of the rules and techniques for the interchange of data between the different framework components and the BIM data.
