1 Project Overview
Shanghai Zhengda Real Estate is the flagship company of Zhengda Group’s real estate division and is publicly listed on the Hong Kong Main Board. The company specializes in developing and managing high-quality residential and commercial real estate projects. Notable urban complex developments include the Shanghai Himalayas Center and Thumb Plaza.
The Nanjing Zhengda Thumb Project represents the continuation and upgrade of Zhengda Real Estate’s Thumb Commercial Real Estate brand in Nanjing. Situated southeast of Nanjing South Station, the project spans a total area of 93,526.4 m² with a planned total construction area of approximately 628,835.4 m². Notably, this project marks the first large-scale commercial complex within the company to implement BIM technology.
Rendering of Nanjing Zhengda Thumb Project
2 BIM Application Practice
The BIM implementation for this project is structured across three levels: the planning layer, the implementation layer, and the assurance layer.
Nanjing Zhengda Thumb Project BIM Third Floor Framework Diagram
The planning layer defines the project’s BIM goals and application strategy, guiding the overall direction. These plans are established and unanimously approved by company or project management. The implementation layer specifies BIM application methods during project execution, developed by the BIM execution team and approved by management. The assurance layer outlines the conditions and resources required to support BIM application, subject to review by management.
2.1 BIM Application Objectives
Setting clear BIM application objectives is vital, as it influences the overall value assessment of BIM integration within the project. Objectives follow the SMART criteria and serve as the foundation for all BIM activities, including identifying application points, selecting service providers, and contract development. These objectives also account for the project’s key challenges and company management processes. After finalizing objectives, relevant stakeholders at both company and project levels clarify BIM goals. For this project, specific targets were developed for design, construction, and cost management through BIM technology.
2.2 BIM Application Planning
BIM application planning involves creating practical, step-by-step plans aligned with the project timeline and company development goals. Each step includes clearly defined conditions and objectives. For organizations new to BIM, the initial focus is developing BIM-based workflows that clarify when and how tasks should be executed. These workflows build upon existing company processes and organize activities according to implementation targets. Activities include main events, prerequisites, execution steps, role responsibilities, deliverables, and completion standards.
As the first large-scale commercial complex project adopting BIM for our company, the Nanjing Zhengda Thumb Project required the BIM consultant to prepare a project-level consulting report. This report was based on internal management processes and the current state of Zhengda Company, developed through extensive research and interviews. Additionally, BIM application standards tailored to the company’s characteristics were developed under headquarters’ guidance.
BIM Consulting Report Catalog
Division of Responsibilities and Flowchart
2.3 BIM-Assisted Design
During the design phase, BIM application points are developed to address the unique characteristics and challenges at each project stage. BIM modeling forms the foundation, but the key focus is on how the models are applied effectively. Due to the large scale and frequent functional layout changes in the Nanjing Thumb Square project, an area model was created during the initial expansion phase to dynamically monitor the building area of each structure and floor, as illustrated below.
Area Statistics Report
Given the relatively low floor heights (three basement levels including 3.5 m for B2 and 3.7 m for B3, with the lowest above-ground floor at 3.15 m), space constraints are significant. Beyond collision detection and pipeline coordination, BIM’s key focus in the design phase is net height review. From initial expansions focusing on main routes and trunk lines to detailed construction drawing stages considering sprinkler heads and maintenance space, BIM models are constantly updated for net height inspections. Findings are verified and fed back to the construction drawing design team. Early in the process, the BIM team highlights net height issue zones to designers, enabling rapid problem identification and coordination to avoid isolated issue resolution.
Clear Height Area Analysis and Positioning Map
During the construction drawing phase, the BIM team collaborated closely with the general contractor’s mechanical and electrical installation teams to integrate pipeline layouts. Mechanical and electrical installation requirements were incorporated comprehensively into the model and communicated back to the construction drawing designers. After multiple rounds of modeling, review, and adjustment, the net height in complex basement areas and public walkways met requirements following pipeline optimization. The images below illustrate a local net height increase from 3.0 m to 3.1 m achieved through BIM-assisted pipeline adjustments in collaboration with the design team.
Net Height Analysis and Comparison Chart Before and After Adjustment
Another challenging aspect is the curtain wall section, which involves complex shapes and optimization. The design phase required careful consideration of collisions between the curtain wall and the main structure, as well as interactions with roof electromechanical systems. Below is a collision report between the curtain wall glass wing and the top floor slab.
Collision Report between Curtain Wall and Main Structure
The overall BIM model for Phase I of the Thumb Project is shown below:
Screenshot from the External Roaming Video of the First Phase BIM Model
2.4 BIM Collaboration in Bidding and Tendering
The bidding process is a critical milestone but is constrained by a tight schedule of approximately one month. Requiring bidding parties to submit BIM construction phase application reports within such a short timeframe poses challenges. Firstly, it limits the ability to evaluate actual BIM implementation effectiveness, as bidding parties may temporarily mobilize resources to meet requirements, not reflecting normal performance. Secondly, it increases the workload and complexity for the owner’s bid evaluation team. To address this, the project introduced a two-stage BIM evaluation process alongside bidding.
(1) Round 1: BIM Open-ended Questionnaire and Survey
This stage involves formulating open-ended questions based on key BIM challenges for the project, considering the contracting system and company management. Bidders submit written responses supported by relevant project cases (no generic internet content). Representatives from these projects are then selected for site visits, focusing on both BIM work quality and actual pipeline layouts related to BIM outcomes.
(2) Round 2: Assessment of BIM Practical Application Capability
A practical evaluation method tailored to the project’s BIM application is developed, incorporating current project drawings. Assessment methods include modeling, earthwork construction simulation, concrete volume calculation, and basement net height requirement assessment based on initial drawings.
Assessment criteria and procedures are internally reviewed and approved, with fairness and impartiality emphasized. The goal is to select competent bidding units, with relative rankings established before the official bidding phase. This approach reflects BIM professionalism without impacting bidding schedules and allows bidders to focus on construction technology and business capabilities.
When all bidders submit reports under consistent requirements, their strengths and capabilities become clear, facilitating consensus within the company. BIM application capabilities are also evaluated from multiple perspectives, such as total basement concrete volume calculations. The project’s investment consulting firm calculated quantities using traditional 2D CAD drawings as a benchmark accepted by the company’s cost control. BIM-based calculations from bidders were then compared against this benchmark. Results showed that basement concrete estimates from two bidders differed by less than 1%, exceeding expectations. The calculations from three bidders fell within a 5% error margin, significantly reinforcing confidence in BIM calculations within the company’s cost control framework.
2.5 Reflections on BIM Application During the Design Stage
BIM application direction was established during the project’s conceptual phase. To save resources, improve efficiency, and shorten timelines, basic requirements were set to transfer BIM models from design to construction stages. Model planning in design must therefore incorporate construction considerations. One key requirement is splitting models by floors and specialties, as shown below, enabling extraction of models by specific disciplines and floors during construction.
Modeling methods for components have been standardized in line with construction needs—walls and columns modeled by floors, beams by spans, and floor slabs by segmented areas. This uniformity ensures the design model aligns with construction models. Additionally, the general contractor’s BIM team regularly reviews design-stage models to incorporate construction and installation pipeline requirements. Owners may request adoption or modifications based on rationalization suggestions from the general contractor.
3 Summary
The construction drawing phase is nearing completion, with construction-phase BIM activities progressing systematically. Although construction-phase BIM application has not officially started, six months of BIM practice has yielded valuable insights for commercial real estate projects:
(1) BIM application should be tailored to the unique characteristics of each real estate project.
(2) BIM technology must support core design and construction tasks, with any application generating tangible value to maximize BIM’s potential.
(3) Modeling is a means, not an end. The goal is to leverage models to create value. Model accuracy must correspond to the application objective and is fundamental to all BIM uses.
(4) Process reengineering and optimization driven by BIM are critical and challenging aspects of BIM application.
Author’s Profile
Wan Zuyong
BIM Manager, Design Management Department, Jiangsu Zhengda Commercial and Cultural Development Co., Ltd.
Wu Yaolong
General Manager, Design Management Department, Jiangsu Zhengda Commercial and Cultural Development Co., Ltd.
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