Container House Ground Beam Design

The design of the ground beam for container houses requires comprehensive consideration of structural strength, load distribution, rust and corrosion prevention, and foundation adaptability. The core design points are as follows:

1. Ground Beam Structural Strength and Load Distribution

The ground beam of a container house needs to bear both vertical and horizontal loads (such as wind loads and seismic forces) of the entire structure. Its design should work in conjunction with the foundation levels. For example, in a four-step stepped strip foundation, the third step uses a 50cm×90cm oversized ground beam with a height of 1 meter as the core load-bearing framework. By expanding the cross-sectional dimensions, it enhances resistance to tension and settlement while transferring the loads to the lower foundation to avoid local stress concentration. For the ground beam steel, it is recommended to use welded weathering steel (GB/T 4171) or Q345B (GB/T 1591) to ensure that the yield strength and toughness meet the seismic fortification requirements (≤8 degrees) for low-rise or multi-story modular houses (with a number of floors ≤6 and a height ≤24m).

2. Connection Method between the Ground Beam and the Foundation

The ground beam needs to transfer loads to the foundation or the lower container through corner fittings. In a pure steel frame structure, the load path is 'panel secondary beam → main beam → corner column → corner fitting → foundation'. The corner fitting is the only stacking load-transfer point, and it should be fixed with high-strength bolts or welding. Spot welding is prohibited as a substitute. If a strip foundation is used, a pre-embedded steel plate should be set at the bottom of the ground beam and connected to the foundation through welding or bolts to ensure overall stability. If a pile foundation is used, the ground beam should be arranged across the piles to avoid excessive overhang sections that could weaken the stiffness.

3. Rust and Corrosion Prevention and Durability Design

Since the container ground beam is a steel component, it requires special protection against rust. During the design phase, the following requirements should be specified:

1. Cutting and Welding Treatment: All cut edges should be ground smooth and painted with epoxy primer + topcoat with a thickness of not less than 120μm.
2. Regular Inspection and Repainting: In inland dry areas, a comprehensive repainting of the anti-corrosion paint is required every 8-12 years; in southern humid areas, every 7-10 years; and in coastal areas, every 3-5 years.
3. Foundation Elevation: The bottom of the ground beam should be at least 20cm above the ground to avoid moisture erosion, and a drainage slope should be set to prevent water accumulation.

4. Foundation Adaptability Design

The design of the ground beam should match the type of foundation:

1. Flat Site: Foldable container houses or fixed residential container houses can be directly placed on a leveled ground, but it is recommended to pour a 10-15cm thick cement cushion for leveling.
2. Strip Foundation: Packed container houses can use a strip foundation, and the width should cover the projection range of the ground beam. The depth should be determined according to the soil freezing line.
3. Pile Foundation: For soft soil foundations, a pile foundation should be used, and the ground beam should be arranged across the piles. The pile spacing should be determined through calculation to avoid bending deformation of the ground beam.

5. Spatial Combination and Expandability

If multiple containers are spliced together, the ground beam needs to reserve connection nodes. For example, when splicing containers horizontally, the ground beams should be aligned and provided with connection plates and fixed with bolts. When stacking containers vertically, the corner fittings of the upper ground beam should be locked with those of the lower one to ensure continuous load transfer. In addition, the design of the ground beam should consider the possibility of future extensions and reserve load margins.