How to Solve Temperature Stress Problems in Large-Area GRC Curtain Walls? Stress Control Technology and Practical Solutions

Large-area GRC curtain walls are prone to thermal expansion and contraction due to temperature changes, generating thermal stress. If not effectively controlled, this can easily lead to component cracking, sealant detachment, loose connection points, and other issues. Developing a scientific thermal stress control plan requires multi-dimensional coordination across design, materials, and construction. Drawing on 28 years of experience in large-scale projects, Qinglong analyzes the core solutions and practical approaches.

1. Expansion Joint Design: The Core Method for Releasing Thermal Deformation

Properly setting expansion joints is key to releasing thermal stress and must be scientifically planned based on the linear expansion coefficient of GRC materials (approximately 10×10⁻⁶/°C) and the curtain wall area. Horizontal expansion joints should be spaced ≤6m apart and vertical expansion joints ≤8m apart, with joint widths set at 20-30mm and filled with elastic sealant, providing a deformation capacity of ±15mm to effectively absorb thermal deformation and prevent cracking from component compression. In Qinglong's 120,000-square-meter GRC roofing project at the Hainan International Convention and Exhibition Center, expansion joints were set at 5m intervals, successfully coping with temperature variations in the tropical region (with day-night temperature differences reaching 15°C). Expansion joints should avoid visually focal areas and adopt concealed designs that ensure functionality without compromising appearance. High-elasticity silicone sealant should be selected to ensure stable long-term expansion and contraction performance.

2. Material and Structural Optimization: Enhancing Stress Adaptability

Optimizing material formulations and component structures enhances the overall thermal stress resistance of GRC curtain walls. In terms of materials, increasing the alkali-resistant glass fiber content to 3%-4% improves the tensile strength and toughness of components, reducing cracking caused by thermal deformation. Qinglong's test data shows that after increasing the fiber content, the crack resistance of components improved by 40%. In terms of structure, thin-wall lightweight designs reduce component self-weight and heat capacity, slowing heat transfer, while steel mesh set inside components enhances overall rigidity and disperses thermal stress. For curved and double-curved components, their geometric characteristics can be used to disperse thermal deformation and avoid stress concentration. The hyperbolic GRC curtain wall of the Guangxi New Media Center effectively mitigated thermal stress effects through its curved structure.

3. Flexible Connection Nodes: Key Design for Absorbing Deformation

Using flexible connection nodes allows components to undergo slight displacement during temperature changes, preventing stress transfer to the main structure. Connectors should be stainless steel sliding bearings or elastic gaskets, allowing horizontal displacement of ±5mm and vertical displacement of ±3mm, to absorb thermal deformation and minor structural settlement. In the Pingshan High-tech Zone Comprehensive Service Center project in Shenzhen, Qinglong adopted flexible sliding bearings to ensure the large-area GRC curtain wall could expand and contract freely with temperature changes. Connection nodes require anti-corrosion treatment, with PTFE gaskets on sliding surfaces to reduce friction and prevent abnormal noise or wear during displacement. The fastening status of nodes should be checked regularly to ensure the flexible function works properly.

4. Construction and Maintenance Control: Reducing Stress Accumulation Risks

Scientific management during construction and maintenance reduces thermal stress accumulation and ensures long-term curtain wall stability. During construction, install components at suitable temperatures (5-30°C), avoiding forced assembly in high or low temperature environments to reduce initial stress; follow the installation sequence of "center to both sides," reserving expansion space to prevent stress concentration caused by accumulated errors; during the curing stage, use constant-temperature, moisture-retaining curing to reduce internal temperature gradients in components and prevent early cracking. During the maintenance stage, regularly check sealant aging and expansion joint clearance, conduct a comprehensive inspection every 2 years, promptly replace aged sealant, and clear debris from expansion joints. In the Qingpu R&D and production project in Shanghai, Qinglong's regular maintenance ensured the large-area GRC curtain wall remained free of thermal stress damage over many years of use, fully validating the effectiveness of the comprehensive stress control plan.