Thickness of Prefabricated Concrete House Wall Panels
The thickness of prefabricated concrete house wall panels typically ranges from 120 mm to 150 mm. The following provides an explanation from three aspects: thickness range, design basis, and existing issues.
Thickness Range and Design Basis
Prefabricated concrete house wall panels, also known as prefabricated concrete panel walls, are designed with a thickness that balances structural strength and material economy. The range of 120 mm to 150 mm is a general standard established in early construction practices: a thickness of 120 mm can meet the basic separation requirements of non-load-bearing partition walls and is suitable for dividing indoor spaces; a thickness of 150 mm is used for some light-load-bearing structures, such as exterior walls or partition walls in low-rise residential buildings. This range is calculated based on the compressive strength of concrete materials at the time (usually C15-C20) and the reinforcement configuration (such as Φ4-Φ6 cold-drawn steel wire mesh), aiming to balance self-weight and load-bearing capacity.
Correlation Between Thickness and Performance
The thickness of wall panels directly affects their physical properties. Thinner wall panels (e.g., 120 mm) are lighter in weight, facilitating transportation and installation, but they have poor thermal insulation performance and a high thermal conductivity coefficient, requiring additional insulation layers. Thicker wall panels (e.g., 150 mm) can enhance structural stability but increase the overall load on the building, posing higher requirements for foundation design. Additionally, thickness is related to the width of the joints between panels; insufficient thickness can lead to stress concentration at the joints, accelerating cracking and water leakage.
Existing Issues and Reasons for Prohibition
Despite meeting early standards, prefabricated concrete panel walls have fundamental flaws: 1. Poor thermal insulation performance: The low thermal resistance of single-layer concrete structures makes it difficult to meet current energy-saving standards (e.g., the requirement in the Design Standard for Energy Efficiency of Public Buildings GB50189-2015 for a wall heat transfer coefficient ≤ 0.6 W/(㎡·K)). 2. Insufficient structural stability: Hollow or lightweight core designs result in weak lateral force resistance, making them prone to overall overturning under seismic or wind loads. 3. Limited load-bearing capacity: The concrete grade and reinforcement configuration cannot support the multi-story load requirements of modern buildings, posing safety risks. 4. Joint seam issues: Panels are filled with mortar or sealant at the joints; long-term thermal expansion and contraction can cause cracks to expand, leading to leakage and air infiltration.
Based on the above issues, China's Code for Fire Protection Design of Buildings GB50016-2014 and the Technical Standard for Prefabricated Concrete Buildings GB/T51231-2016 have explicitly restricted the use of prefabricated concrete panel walls, recommending the use of cast-in-place concrete shear walls or new prefabricated wall panels (such as autoclaved aerated concrete panels and steel truss floor panels) instead.
