Are There Different Connection Methods for GRC Panels with Different Curvatures?

The connection methods between GRC panels of different curvatures do indeed differ significantly, with their design core centered on three functional requirements: "accommodating deformation, transferring loads, and achieving sealing." In its GRC curtain wall projects, Qinglong Group customizes differentiated connection solutions based on the type of curved surface (single-curved or double-curved), the magnitude of curvature, panel dimensions, and the characteristics of the building's main structure.

The connection between single-curved panels is relatively regular. When two panels have the same or similar curvature, they can be regarded as part of a continuous surface with a larger radius. Qinglong typically adopts a "fixed-axis rotation" hook-on system, in which the connection points are designed to allow the panels a slight rotational freedom along the tangent direction of the curvature, so as to accommodate deformations caused by temperature changes. The joints are mostly treated with equal-width sealant joints, and the sealant must have sufficient movement capability (e.g., ±25%).

The connection between double-curved panels is far more complex. Since a double-curved surface bends in three-dimensional space, adjacent panels deform differently in every direction. For such connections, Qinglong has designed a three-way adjustable universal-joint bracket system that allows a certain amount of adjustment in each of the X, Y, and Z directions (typically ±10mm each). Connection points are usually located at the corners of panels or in areas where the curvature changes gradually, to avoid generating excessive internal forces in high-curvature regions. For complex double-curved curtain walls such as the Nanning New Media Center, Qinglong even customized unique attachment coordinates for each panel and carried out virtual pre-assembly through a BIM model to ensure precise on-site alignment.

The transitional connection between panels of different curvatures is a design challenge. When a flat panel meets a single-curved panel, or a single-curved panel meets a double-curved panel, the connection system must be capable of "gradual stiffness transition." Qinglong's approach is to set relatively flexible connections on the stiffer flat-panel side, while using more strongly restrained connections on the relatively flexible curved-panel side, so that deformations are coordinated. At intersections of different shapes, "transition fittings" or "transition panels" are often used to break drastic geometric changes into gradual transitions. All connection designs are verified through finite element analysis to ensure that, under wind loads, seismic action, and temperature changes, the connection system remains safe and reliable and the sealing system remains effective over the long term.