Design Methods and Key Technologies for Connection Joints Between UHPC Curtain Wall Panels and Steel Frame Keels: A Discussion

In contemporary building envelope technology, the connection joints between UHPC curtain wall panels and steel framing keels are like the "structural hubs" of a building; the rationality of their design directly affects the building's safety, durability, and aesthetic presentation. As an industry player with 28 years of deep engagement in the UHPC/GRC/GRG/GRP materials field, Qinglong Group has witnessed the entire journey of ultra-high performance concrete from the laboratory to landmark buildings, and has accumulated systematic solutions especially in connection joint technology.

### Technical Pain Points and Design Logic of UHPC Curtain Wall Panel Connection Joints

UHPC (ultra-high performance concrete), with its compressive strength exceeding 150MPa and elastic modulus close to that of steel, is an ideal material for long-span curtain walls. However, its connection with steel framing keels must resolve three core contradictions: material rigidity matching, thermal deformation coordination, and long-term load transfer. Traditional wet-connection processes are prone to stress concentration, while purely mechanical connections face challenges in corrosion protection and durability. Experimental data from Qinglong's Nanning production base show that a composite joint design of "pre-embedded sleeve + elastic gasket" can increase joint fatigue strength by 40%, and this technology has been successfully applied to several convention and exhibition center projects in China.

### Key Technical Path: From Material Selection to Construction Methods

The technical core of joint design lies in building a force-transfer system that combines rigidity with flexibility. At the material level, Qinglong's specially developed pre-embedded steel components for UHPC are made of 316L stainless steel, combined with a basalt fiber-reinforced transition layer to effectively solve the problem of electrochemical corrosion. In construction, joints are parametrically modeled using BIM technology, and 3D scanning keeps installation errors within ±2mm. Notably, joint waterproofing details require differentiated designs for different climate zones—rainy regions adopt a combination of multiple sealing strips and water drainage channels, while cold regions focus on strengthening thermal bridge insulation. These details were fully validated in an ice and snow sports center project in Shenyang that Qinglong participated in.

### Full-Chain Service Empowering Joint Implementation Results

As a national-level high-tech enterprise integrating detailed design, manufacturing, and construction installation, Qinglong has established a full lifecycle management system for joint technology. In the design phase, joint deformation under 150-year wind pressure loads is simulated with finite element analysis software; in production, automated pre-embedding positioning tooling ensures embedded part position deviation of ≤1mm; and on-site installation is equipped with dedicated torque wrenches and stress monitoring equipment. This seamless "design-production-construction" integration enabled millimeter-level installation precision for more than 2,000 translucent UHPC curtain wall panels in the Nanjing East Road Century Plaza renovation project, winning the Silver Award at the first UHPC Construction Engineering Innovation Awards.

### Industry Trends and Qinglong's Practice

With the advancement of the industry standard "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)," joint design is developing toward modularity and replaceability. This standard, which Qinglong helped compile, for the first time specifies fatigue performance testing methods for connection joints. In a landmark project in Saudi Arabia, Qinglong innovatively adopted a detachable joint design, enabling rapid replacement and maintenance of UHPC curtain wall panels, and this technical solution has been filed for an invention patent.

From the hyperbolic GRC curtain wall of the Guangzhou Opera House to the UHPC envelope of the Nanning ASEAN Culture and Arts Center, connection joint technology has always been the key point where material performance meets architectural aesthetics. Building on 28 years of industry experience and continuous technological innovation, Qinglong is driving UHPC curtain wall systems toward greater safety, durability, and design expressiveness, providing designers and owners with full-chain solutions from concept to implementation.