Solution Guide · Underground Parking Structures
Taidi System Technical Whitepaper: Post-Tensioned Wide Flat Beam Solution for Covered Underground Garage Roofs
Covered underground garage roofs face combined loads from soil cover, fire truck loads, and groundwater uplift. Flat slabs risk punching shear, while conventional beam-slab systems increase floor height. The Taidi system uses post-tensioned wide flat beams to save approximately 500 mm in floor height and excavation depth compared to beam-slab systems, and eliminates punching shear risks versus flat slabs. This whitepaper details technical principles, comparisons, and applicable conditions for commercial developers and structural designers.
Intended Readers
Owners, investors, operators, design teams and general contractors who need preliminary engineering assessment for the applicable scenario.
Applicable Scenarios
Underground Parking Structures
Key Engineering Questions
1. The Challenge: Why Covered Garage Roofs Are Difficult
Covered underground garage roofs are structurally complex due to three superimposed loads:
- Soil cover self-weight: Typically 0.5–1.5 m thick, creating large uniform loads.
- Concentrated loads: Planting beds and fire truck loads (≥20 kN/m²) cause local stress concentrations.
- Groundwater uplift: High water tables require coordinated anti-float and roof design.
Traditional solutions face limitations:
Option A: Flat Slab
Simple construction and good headroom, but punching shear risk increases with soil cover >0.6 m. Review authorities often reject such designs.
Option B: Conventional Beam-Slab
Safe but requires beam depths of 800–1000 mm, increasing floor height by >800 mm, excavation depth, and waterproofing costs.
2. Taidi System Technical Logic
Post-Tensioned Wide Flat Beams: Flat but Strong
- Wide: Larger beam width provides bending capacity.
- Flat: Minimal beam height (200–300 mm above slab) preserves headroom.
- Post-tensioned: Active bending moment compensates for reduced depth.
Result: Sufficient load capacity without punching shear risk.
Comparison
| Aspect | Flat Slab | Conventional Beam-Slab | Taidi Wide Flat Beam |
|---|---|---|---|
| Soil cover adaptability | Difficult >0.6 m | Adaptable, but deep beams | Adaptable, no review issues |
| Floor height impact | Minimal | +800 mm | +200–300 mm |
| Excavation depth | Shallow | Significantly deeper | Reduced depth |
| Column count | Many | Many | Reduced by >60% |
| Safety | Punching shear risk | High | High |
3. Key Value Data
- Floor height and excavation savings: ~500 mm vs. conventional beam-slab, reducing earthwork, shoring, dewatering, and anti-float measures.
- Column reduction: >60% fewer columns, improving parking layout and traffic flow.
4. Applicable Conditions
Ideal for projects with:
- Soil cover ≥0.5 m
- Clear height or FAR requirements
- Flat slab designs failing review
- Cost control with safety assurance
Can be combined with Taiping integrated floor system for seamless flooring.
Download or Inquiry
Full technical documents may require contact information for delivery and follow-up explanation. Submit a project inquiry if you need the complete resource or scenario-specific guidance.