Construction of the Foundation for Multi-Span Film Greenhouse

A multi-span film greenhouse is an efficient and energy-saving agricultural facility suitable for large-scale cultivation, seedling propagation, or scientific research and production. Its foundation construction is a core step to ensure the structural stability and service life of the greenhouse. Below is a detailed process and key points of its foundation construction.

I. Pre-construction Geological Survey

Confirm soil bearing capacity through geological exploration (recommended ≥120 kPa), groundwater level, and frost depth (in northern regions, deeper burial is required to prevent frost). Level the terrain: remove weeds and stones to ensure a site slope ≤3% and avoid water accumulation. Confirm drawings: design foundation dimensions and layout based on greenhouse span (commonly 8m/9.6m) and height (eave height 3-4m, ridge height 5-6m).

II. Material Preparation

C25/C30 concrete, Φ12-16mm threaded steel bars (foundation reinforcement), embedded parts (anchor bolts/steel plates). Auxiliary materials: PVC drainage pipes, weed barrier fabric, waterproofing membrane. Tools: total station (for positioning), excavator, vibrator, formwork (steel or wood).

III. Foundation Construction Process

1. Setting out and positioning: Mark column positions with a total station according to the drawings, with an error ≤2cm. For multi-span greenhouses, ensure alignment of adjacent span axes to avoid deviations during frame installation.

2. Foundation treatment: Excavate pits; single-column foundation dimensions are typically 50×50×60cm (L×W×D), with a 10cm gravel cushion at the bottom. Reinforcement: configure 4 Φ12mm longitudinal bars + stirrups @200mm, and embed anchor bolts (exposed 15-20cm). Pouring: pour concrete in layers, compact with vibration, finish the surface, and cure for 7 days. Excavate trenches 40cm wide and 50cm deep, configure continuous reinforcement cages, and embed column connection plates.

3. Ring beam construction: For spans ≥10m or areas with high wind, add a ground ring beam (cross-section 30×30cm) to enhance overall wind resistance.

4. Drainage system: Dig drainage ditches around the greenhouse (30cm wide × 40cm deep) with a 0.5% slope, lined with PVC pipes or brickwork for diversion.

5. Embedded part calibration: Correct the position of anchor bolts before initial concrete setting, with horizontal error ≤3mm and elevation error ≤5mm.

IV. Key Quality Control Points

1. Concrete strength: 28-day compressive strength must meet design values (C25≥25MPa); add antifreeze agents for winter construction.

2. Settlement prevention: In soft soil areas, replace with sand and gravel or reinforce with piles (e.g., pipe pile depth ≥2m).

3. Rust and corrosion prevention: Embedded steel components must be hot-dip galvanized (zinc coating ≥80μm), with welded areas recoated with anti-rust paint.

4. Wind resistance design: Foundation burial depth must exceed the local maximum frost depth by 30cm (e.g., burial depth ≥1.2m in northeastern regions).

V. Construction Safety and Environmental Protection

1. Set up警戒 zones when operating machinery; wear hard hats and reflective vests.

2. Sort and stack waste concrete and debris to avoid contaminating farmland.

3. Cover with waterproof tarps during rainy season construction to prevent foundation pit collapse.

VI. Common Issues and Solutions

1. Uneven foundation settlement: Immediately stop construction and use grouting reinforcement or additional piling.

2. Embedded part deviation: Correct by welding steel plates; if deviation >10mm, reinstall reinforcement.

3. Poor drainage: Add catchment pits or enlarge drainage ditch cross-sections.

Through scientific and standardized foundation construction, multi-span film greenhouses can withstand Level 10 winds and 20cm snow loads, with a service life of over 15 years. Henan Green Union Greenhouse designs and constructs various types of greenhouses, with an experienced construction team and professional after-sales service. Customers in need are welcome to inquire and purchase. Service hotline: 13333863757