## 7 The Proposed Framework for BIM-Based Value Engineering Within a Common Data Environment (CDE)  
The proposed framework integrates Building Information Modeling (BIM) with Value Engineering (VE) within a Common Data Environment (CDE), focusing on enhancing project outcomes by improving decision making, reducing costs, and ensuring that project goals align with client requirements. This framework was specifically designed to be implemented during the pre-construction phase, where the impact of design decisions is most significant. In the pre-construction phase, it is crucial that the stakeholders and design teams work cooperatively to prevent common design issues, such as changes in design, clashes between elements, constructability problems with the proposed design, and inadequate 2D drawings [32].  
The proposed framework was implemented in a prototype model developed to support the VE team in evaluating and ranking different design alternatives for project components using multi-attribute criteria. Aside from the 3D geometrical model, it uses AHP to assist the VE team in evaluating competing alternatives. The project BIM model was created using Autodesk software (Revit 2024) and was used to create the 3D model and extract the required project data. The proposed method is intended to assist VE team members in performing the evaluation process with relative ease and in less time. Furthermore, it enables them to understand the consequences of alternative changes visually and numerically. Figure 5 summarizes the framework implementation sequence.  
The framework was structured into four main modules, as shown in Figure 6. Each addresses a critical aspect of the VE-BIM integration process within a CDE:  
1. Module 1--Creating the CDE: The first module involves establishing a CDE to serve as the single source of truth for all project-related information. The CDE securely stores all documents, BIM models, and VE ideas, ensuring that stakeholders can access the most current data. This centralized repository not only facilitates collaboration but also supports the efficient management and retrieval of information throughout the lifecycle of the project.
2. Module 2--Design BIM Model Development: The second module focuses on developing a detailed BIM model up to LOD 300, incorporating all necessary geometric and semantic data. This model serves as the foundation for VE analysis and is enriched with parameters related to the OmniClass classification system. By integrating these classifications into the BIM, the framework enhances the ability to conduct targeted searches and apply relevant VE ideas.
3. Module 3--Value Analysis/Engineering Model: In this module, the VE team uses the BIM model and CDE to evaluate and rank different design alternatives based on multi-criteria decision making. The Analytical Hierarchy Process (AHP) is employed to automate the evaluation, allowing for the systematic comparison of alternatives.  
The VEIDEA data bank, which stores past VE ideas, is a key resource in this process, enabling the team to leverage historical data to inform the current decisions.
* Module 4--Value Engineering Study: The final module streamlines the VE study by utilizing integrated BIM and CDE resources. The VE team can easily access all the necessary information, generate innovative alternatives, and assess the impact of the proposed changes on the project's overall value. The framework's use of BIM visualization tools enhances the team's ability to understand and refine design options before construction begins.  
Figure 5: Sequence of framework implementation.  
The goal is to select the most appropriate alternative by considering multi-attribute criteria that satisfy the owner requirements and project objectives. Each module has a dedicated subsection that explains its functions in detail.