Load-Bearing Capacity Calculation of UHPC Panels Used as Floor Slabs: Code Methods and Qinglong Engineering Practice

When UHPC panels are used as floor slabs, load-bearing capacity calculation must incorporate material properties, panel type parameters, support conditions, and service loads, following the “Code for Design of Concrete Structures” (GB50010) and the “General Technical Conditions for Ultra-High Performance Concrete (UHPC) Non-Load-Bearing Components” to ensure structural safety. Leveraging 28 years of structural engineering experience, Qinglong Group has established a calculation system of “parameter selection – load combination – strength verification – deflection verification,” which has been successfully applied in floor slab projects such as industrial plants and high-end residences, achieving a load-bearing capacity calculation accuracy rate of over 99%.

1. Core Calculation Parameter Selection: Based on Material and Panel Characteristics

Material property parameters: UHPC compressive strength f_cu,k≥150MPa, flexural strength f_tk≥30MPa, elastic modulus E_c=3.5×10⁴-4.0×10⁴MPa. Qinglong uses its independently developed UHPC formulation, with measured parameters exceeding code requirements, providing a safety margin for calculations. Panel type parameters: floor slab thickness is typically 30-50mm, aspect ratio ≤2.0 (one-way slab) or >2.0 (two-way slab), with support conditions treated as simply supported or continuous beams. In the floor slab design for an industrial plant, Qinglong adopted a 40mm-thick UHPC panel (one-way slab, 3m span) that met the load requirements. Additional parameters: consider self-weight (25kN/m³×slab thickness), construction load (2.5kN/㎡), and service load (2.0kN/㎡ for residential, 5.0kN/㎡ for industrial), with load combinations calculated as 1.2×dead load+1.4×live load.

2. Core Steps of Load-Bearing Capacity Calculation

Step 1: Determine the calculation model. One-way slabs are calculated as flexural members for tension-zone reinforcement or steel fiber contribution, while two-way slabs are calculated for biaxial bending. Qinglong uses PKPM or SAP2000 software to build models simulating the stress state of floor slabs. Step 2: Flexural capacity verification. The flexural capacity of UHPC panels is jointly carried by steel fibers and reinforcement (by steel fibers alone if unreinforced), with the formula M≤α₁f_cbx(h₀-x/2)+f_yA_s(h₀-a_s). When the steel fiber volume fraction is ≥2%, it can partially replace tensile reinforcement. In a residential floor slab project, Qinglong met the flexural capacity requirement without reinforcement using a 2.5% steel fiber content. Step 3: Shear capacity verification, with the formula V≤0.7f_tbh₀+f_yvA_svh₀/s. UHPC has high shear strength and typically requires no stirrups; in floor slab projects with spans ≤3m, Qinglong used no stirrups while shear capacity still met standards. Step 4: Deflection verification. Per code requirements, floor slab deflection must be ≤L/250 (L is the span). Verified through software calculation and on-site testing, the deflection of a 40mm-thick UHPC floor slab with a 3m span was ≤12mm, meeting requirements.

3. Calculation Optimization for Special Scenarios

Large-span floor slabs (span >4m): increase slab thickness to 50mm or add stiffening ribs (rib height ≥100mm, spacing ≤1.5m). The stiffening rib scheme Qinglong designed for a large-span floor slab (5m span) in a commercial complex increased load-bearing capacity by 50%. Composite floor slabs: the UHPC panel serves as a surface layer (20-30mm thick) composited with the underlying concrete slab, with协同 considered in calculations. In an old building renovation floor slab project, Qinglong adopted this scheme, enhancing load-bearing capacity while reducing self-weight. High-load scenarios (e.g., industrial plants): configure double-layer bidirectional reinforcement in the UHPC panel (Φ8@200) to enhance tensile and shear capacity. The reinforcement scheme Qinglong designed for an equipment plant floor slab met the 8kN/㎡ service load requirement.

4. Qinglong’s Engineering Evidence and Technical Advantages

Project cases: an industrial plant UHPC floor slab (40mm thick, 3m span) achieved a load-bearing capacity of 6kN/㎡ through calculation and on-site load testing, far exceeding the design requirement (5kN/㎡); a high-end residential composite floor slab (30mm UHPC+120mm concrete) met the 3kN/㎡ service load with deflection ≤10mm. Technical support: holds the “UHPC Floor Slab Structural Design” patent and has developed a dedicated calculation software module, improving calculation efficiency by 30%; participated in industry standard development, incorporating the UHPC floor slab load-bearing capacity calculation method into code recommendations. Quality control: after calculation is completed, trial production and load testing are conducted to ensure actual load-bearing capacity ≥1.2 times the calculated value; all of Qinglong’s floor slab projects have passed this verification.

The core of load-bearing capacity calculation for UHPC panels used as floor slabs lies in precise parameter selection and code-based verification, with optimized design combining panel type and load scenarios. Leveraging professional structural design capabilities and engineering practice, Qinglong Group provides customers with safe and economical load-bearing capacity calculation solutions, enabling UHPC panels to fully leverage their lightweight, high-strength advantages in floor slab applications.