The development of prefabricated buildings represents a significant shift in construction methods and is a key strategy to drive supply-side structural reform within the construction industry. This approach helps conserve resources and energy, reduce construction pollution, enhance labor productivity, and improve quality and safety standards. It also promotes the deep integration of the construction sector with information technology industrialization, increasing the overall cost-effectiveness of prefabricated buildings and better aligning with green building requirements.
Currently, prefabricated buildings are in a pilot and exploratory phase, with various uncertainties that need to be addressed and refined. Challenges in bidding and tendering for prefabricated buildings include the absence of national technical regulations, lack of provincial and municipal quantity list specifications, immature bidding and tendering guidelines, insufficient evaluation methods, a limited number of enterprises skilled in construction technology, and the lack of standardized national and provincial bidding procedures. Therefore, bidding practices for prefabricated buildings require ongoing study and practical resolution.
Current Landscape of Bidding for Prefabricated Buildings
Policy Support Across Regions
Multiple regions have enacted policies to strongly support the growth of the prefabricated building sector. The six most common types of policy support are:
- Land Use Guarantees: Priority allocation of construction land for the prefabricated construction industry.
- Area or Plot Ratio Incentives: Typically offering up to a 3% plot ratio reward, excluding prefabricated exterior walls from the building area.
- Financial Subsidies: For example, Shanghai provides a subsidy of 100 yuan per square meter, capped at 10 million yuan per project; Chongqing offers 350 yuan per cubic meter of concrete components.
- Tax Incentives: Policies include reductions or exemptions in corporate income tax and a 50% refund on collected value-added tax.
- Pre-Sale Permissions: Allowing prefabricated commercial housing to be pre-sold once the construction site reaches ±0.000 elevation, enabling the issuance of a “Pre-sale Permit for Commercial Housing”.
- Fund Returns: Exemptions from special funds for new wall materials, with preferential refunds granted after project completion and acceptance.
Prefabricated Building Quotas
To encourage prefabricated building development, many regions have set quotas. Prior to 2016, areas such as Shanghai, Liaoning, Shandong, Anhui, Fujian, Hunan, and Sichuan issued quotas. Tianjin, Henan, Hebei, Zhejiang, and Shenzhen followed in 2016. Inner Mongolia, Qinghai, Jiangsu, Hubei, and Guangdong are expected to introduce quotas soon.
Innovative Regulatory Mechanisms and Contracting Models
Regional regulatory frameworks continue to evolve, with a comprehensive push towards the engineering general contracting model for prefabricated projects. For example, Jinan City awards bonus points during bidding to engineering general contracting firms with component production qualifications and substantial total investment. Enterprises handling integrated design, production, construction, and installation gain priority under equal conditions. In Hefei City, initial pilot projects use a single-source method to select prefabricated construction firms, comparing traditional and industrialized methods to set costs with a profit margin for industrialized enterprises. Eventually, open bidding and design-construction general contracting will be standard, with industrialized enterprises managing the entire process from design to assembly, resulting in lower bid prices and shorter construction periods.
As the market matures and bidding processes standardize, the cost of prefabricated buildings is expected to steadily decline.
Overview of the Bidding Process for Prefabricated Buildings
According to relevant regulations, prefabricated buildings typically adopt the engineering general contracting method, specifically the EPC (Engineering, Procurement, Construction) model. This model covers design, procurement, construction, and commissioning, with unified planning, organization, command, and coordination. Bidding requirements should address construction scale, quality standards, and responsibility divisions.
Key bidder qualifications include:
- Enterprises capable of managing engineering general contracting, such as design firms, construction companies, developers, or project management units.
- Design, construction, or project management units with appropriate qualifications may bid independently or as a consortium.
- Given the limited number of firms with engineering general contracting experience, such performance should not be a mandatory bidding condition to foster industry growth.
Under clear, unified criteria, bidders prepare estimated bills of quantities and submit quotations based on conceptual or design schemes, construction scale, and standards. A lump-sum pricing model is recommended, excluding underground works, which should use a unit price contract with actual measurement. If cost adjustments for materials and labor are necessary, bidders should fix the proportion of these costs in the total project price during bidding. The winning bid’s construction and installation costs, multiplied by this proportion, form the base for settlements, adjusted per pre-agreed methods.
During evaluation, attention should be given to the bidder’s management and performance capabilities, the compliance of detailed designs with bidding requirements, and the reasonableness of the bid price.
Electronic Evaluation of Prefabricated Building Bids
Evaluating bids for prefabricated buildings is challenging, particularly regarding design schemes, construction plans, and pricing. The author suggests that BIM (Building Information Modeling)-based electronic evaluation offers a more scientific and efficient approach.
Establishing a BIM-Based Electronic Bidding System
The bidding and tendering stages should incorporate:
- Model creation or import
- Preparation and optimization of construction plans and schedules (simulation)
- Resource and fund planning and optimization
- Development of specialized construction plans
- Bidding document preparation tools
- Online bidding platforms
- Construction schedule planning and site layout software
- Pricing software
During evaluation, the system should support:
- Construction scheme comparison and assessment
- 5D evaluation (integrating time and cost dimensions)
- Resource planning analysis
- Evaluation of specialized construction schemes
- Design scheme review
- Remote electronic evaluation capabilities and BIM bid evaluation subsystems
Key Aspects of BIM-Based Bid Evaluation
1. Model Checking
Review component details, timeline data, and optimization logic intuitively. Select specific floors and component types for inspection, and verify component parameters, construction plans, and optimization through attribute windows. This transforms traditional textual data into a 3D information model, enhancing the depth and relevance of the evaluation.
2. Progress Simulation
Use 4D animations to visually assess the construction schedule against technical standards. Multiple viewing windows allow evaluation of the construction sequence and logic across different disciplines, replacing traditional charts and text with dynamic visualizations that deepen evaluators’ understanding and improve judgment accuracy.
3. Financial and Resource Inspection
Display bidders’ funding and resource utilization plans in multiple dimensions. Assess the rationality of fund allocation by examining smoothness and consistency across monthly, weekly, and daily time units, facilitating comprehensive and nuanced evaluation.
4. Venue Layout Evaluation
Present the construction site and temporary facility layouts in 3D, combining site models with solid and measurement plan models. This roaming, multi-perspective review improves evaluation accuracy by overcoming the limitations of traditional 2D plans.
5. Key Node Scheme Review
Showcase construction plans for critical or complex tasks through animations and video playback. This intuitive, multimedia approach replaces lengthy textual explanations, enhances expert understanding, and lowers barriers to disclosing detailed construction plans.
6. Bid Quotation Evaluation
Leverage BIM to provide a comprehensive overview of the bill of quantities, presenting the bidder’s commercial proposal at a project-wide level. When combined with big data applications, it facilitates early detection of irregularities or issues in the engineering quotation.
7. Detailed Direct Expense Investigation
Visualize business proposal reviews within selected BIM model areas. Through component selection, framing, and querying, experts can quickly isolate components requiring scrutiny. Presenting bid data at the component level with 3D models and detailed information supports intuitive and thorough problem identification.
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