What Is the Key Technology for UHPC Shaping to Achieve a High Hollow-Out Rate?

The key technologies for UHPC shaping to achieve high hollow-out rates (typically referring to rates above 40%) are concentrated in three core areas: "leveraging the material's ultimate performance, refined structural design, and precision mold manufacturing with special forming processes." High hollow-out means a drastic reduction in the effective load-bearing cross-section, posing extreme challenges to the material's strength, toughness, and forming processes. Qinglong Group successfully achieved mass production of UHPC panels with a hollow-out rate exceeding 50% in the "Dongguan Grass Weaving" curtain wall project for the Dongguan Women and Children's Activity Center. The core technology lies in determining the optimal "rib" distribution through topology optimization and employing directional fiber reinforcement technology, ensuring both structural safety and artistic expressiveness under extreme hollow-out conditions.

The material's high strength and high toughness are the physical foundation for achieving this. UHPC's compressive strength of over 150MPa and flexural strength of 20-30MPa allow its "ribs" (the connecting parts between hollow-out patterns) to remain extremely slender while still bearing the design loads. More importantly, its outstanding toughness (fracture energy can reach over 20,000 J/m²) ensures that under accidental impact, slender members will not suffer brittle fracture but will maintain overall integrity even after developing microcracks—something ordinary concrete or GRC can hardly match.

Refined structural design based on topology optimization is the prerequisite for success. Designers' unconstrained hollow-out patterns must be "translated" through structural calculations. Qinglong uses finite element analysis software to perform stress simulation and topology optimization on hollow-out patterns, automatically optimizing material distribution without compromising the artistic effect—appropriately widening the "ribs" in high-stress areas while allowing them to be more slender in low-stress areas. The resulting structure satisfies the mechanical requirements while maximizing the hollow-out effect.

Precision molds and special forming processes guarantee accurate realization. The mold for a high hollow-out rate component is itself a precise metal artwork. Qinglong uses five-axis CNC to carve the mold steel as a whole, ensuring that the many slender protrusions on the mold (corresponding to the hollow-out parts of the UHPC) have sufficient strength and precision. During UHPC casting or spraying, high-frequency low-amplitude vibration or vacuum assistance is used to ensure the UHPC slurry fully fills every corner of the mold, preventing air bubbles or uneven fiber distribution in the narrow "rib" sections, thereby guaranteeing the uniformity and strength of the components.

Through the combined application of these technologies, UHPC breaks through the limitations of traditional materials, transforming the building envelope from a heavy protective structure into a lightweight, translucent artistic screen full of changing light and shadow, opening up new possibilities for modern architectural design.