How to Ensure Structural Stability of Large-Span GRC Forms? Spanning Mechanics and Qinglong Group's Large-Scale Structural Solution

Ensuring the structural stability of large-span GRC forms (typically referring to unidirectional spans ≥6m or cantilevers ≥3m) is a systematic project involving "high-strength materials, bending-resistant forms, support systems, and reliable connections." Its core lies in leveraging the material properties of GRC to efficiently transfer loads to supports through rational structural form design. Qinglong Group successfully applied solutions such as "thin-shell structures, space grids, and hybrid structures" in projects including the wavy roof of the Hainan International Convention and Exhibition Center (maximum single-panel span of 8m) and the large cantilevered canopy of the Nanning New Media Center (cantilever of 4.5m). Through finite element calculations, full-scale testing, and construction monitoring, the absolute safety of large-span GRC forms was ensured. Achieving large spans relies on the precision of calculation and detailing.

Form Optimization: Utilizing the Spatial Stiffness of Curved Surfaces

The most economical and effective approach is to convert flat plates into curved surfaces, utilizing the spatial load-bearing characteristics of thin-shell structures. Double-curved shells (such as barrel shells and hyperbolic paraboloid shells) possess extremely high in-plane stiffness, enabling large spans with very thin thicknesses (e.g., 20-30mm). Through form optimization algorithms, we seek curved surface forms with maximum stiffness under given boundary conditions, minimizing material usage.

Stiffening Systems: Rib Grids for Enhanced Local Stiffness

When design constraints require larger flat surfaces, stiffening ribs must be installed on the back of the panels. Rib layout (grid pattern, radial pattern) and cross-sectional dimensions (height, width) must be determined through calculation. We often adopt a "concealed rib" design, where ribs and panels are formed in a single casting, ensuring a flat appearance. For extra-large panels, they can be designed as space trusses or grid structures, with GRC serving as the load-bearing skin.

Hybrid Structures: Working in Concert with Steel Frameworks or Cable Nets

For projects with extremely large spans (>12m) or special forms, a hybrid system combining GRC with steel structures or cable-membrane structures is adopted. GRC serves as the decorative surface layer and non-load-bearing envelope, while the primary loads are carried by the internal steel framework or cable net. The two work together through reliable connections. This requires precise deformation compatibility design.

Stability Control During Construction

During demolding, lifting, and installation, large-span components experience load conditions different from—and potentially more adverse than—the service stage, due to self-weight and changing support conditions. Construction stage verification calculations are essential, along with the design of specialized lifting devices, installation frames, and support schemes to ensure safety throughout the entire process from factory to final position. We use BIM technology to simulate the entire installation process.

Ensuring the structural stability of large-span GRC forms requires whole-process control from conceptual design and detailed calculation to construction implementation. With its strong structural design capabilities and extensive practical experience, Qinglong Group is capable of handling various large-span challenges, achieving a perfect fusion of architecture and structure.