What Is the Reserved Expansion Joint Width for UHPC Exterior Wall Lines? Analysis of Key Design Points

True craftsmanship lies in the details—expansion joint design is the invisible guardian of safety and aesthetics in UHPC exterior wall lines.

In the field of modern architectural decoration, UHPC (Ultra-High Performance Concrete) has become the material of choice for high-end building exterior wall lines thanks to its outstanding mechanical properties and artistic expressiveness. As an industry-leading enterprise with 28 years of experience in detailed design, manufacturing, and construction of UHPC/GRC/GRG/GRP materials, Qinglong Group fully understands the critical role of expansion joint design in UHPC exterior wall line applications. Drawing on full-chain technical expertise, this article analyzes the reserved width standards and core design points for expansion joints in UHPC exterior wall lines, providing professional solutions for designers and owners.

I. Scientific Basis for the Reserved Expansion Joint Width in UHPC Exterior Wall Lines

Although UHPC material has low shrinkage properties, internal stress still needs to be released through expansion joints due to temperature changes, humidity differences, and structural loading. According to the "General Technical Conditions for Non-Load-Bearing UHPC (Ultra-High Performance Concrete) Components" (Plan No. 2024-0232T-JC), which Qinglong Group helped develop, and practical experience, the reserved expansion joint width must meet the following standards: in temperate climate zones, expansion joints should be set every 12-15 meters along straight sections, with the width controlled at 10-15mm; in regions with large temperature differences or for extra-long lines (over 20 meters), the width should be increased to 15-20mm and filled with elastic sealing material. These parameters ensure structural safety while preventing excessive joint width from compromising the decorative effect, fully reflecting Qinglong's technical expertise in combining material properties with engineering practice.

II. Four Core Points of Expansion Joint Design for UHPC Exterior Wall Lines

1. Material Compatibility Design: Expansion joint sealing materials must match the physical properties of UHPC. Qinglong recommends weather-resistant silicone sealant or polyurethane elastomer with an elongation rate of ≥200% to maintain sealing performance through temperature cycles. Meanwhile, a PE rod should be placed inside the joint as backer material to prevent over-compression of the sealant—a detail derived from the construction experience of Qinglong's 2,000+ projects.

2. Structural Joint Optimization: Using a "broken joint, continuous reinforcement" design, the UHPC line body is interrupted at the expansion joint while load transfer is achieved through built-in stainless steel connectors, meeting deformation requirements while ensuring overall stability. Qinglong has standardized this joint in precast components at its Nanning production base, improving construction efficiency by 30%.

3. Integrated Aesthetic Treatment: Leveraging the plasticity of UHPC material, expansion joints are integrated into the line profile, such as using grooved or beveled designs to conceal the joint openings. In the Century Plaza renovation project on Nanjing East Road, Qinglong transformed expansion joints into textural elements of decorative lines through parametric design, achieving unity of functionality and aesthetics.

4. Full Life-Cycle Considerations: Access channels for maintenance are reserved at the detailed design stage, combined with Qinglong's self-developed RFID chip traceability system to facilitate later maintenance and replacement. This "forward-looking design" concept reduces the maintenance cost of UHPC exterior wall lines by more than 40%.

III. Qinglong Group's Technical Empowerment and Industry Practice

As a national high-tech enterprise and developer of multiple industry standards, Qinglong Group integrates 28 years of technical expertise into full-chain services for UHPC exterior wall lines: from expansion joint simulation analysis during BIM model construction, to precision mold machining in production (tolerance ≤0.5mm), to 3D laser positioning during on-site installation, forming a standardized solution. For example, in the Dongguan Women and Children's Activity Center project, Qinglong optimized expansion joint spacing and sealing techniques, ensuring the UHPC lines remained crack-free and leak-free after 5 years of use, winning the AALBORG WHITE Cup GRC Construction Engineering Innovation Award.

Expansion joint design for UHPC exterior wall lines is a comprehensive embodiment of materials science, structural mechanics, and architectural aesthetics. Qinglong Group has always upheld the mission of "creating beautiful architecture," taking details to the extreme through professional technology. Going forward, we will continue to focus on UHPC/GRC/GRG/GRP material innovation, providing safer, more durable, and more artistically valuable decorative solutions for global building projects, and working hand in hand with partners to create architectural beauty together.