How Much Gap Width Should Be Reserved When Splicing UHPC Panels: Reasonable Standards and Construction Recommendations

In the construction and installation of UHPC panels, reserving the width of joint gaps is a critical factor affecting project quality and aesthetics. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP materials, Qinglong Group combines detailed design, manufacturing, and construction practice to provide designers and owners with scientific and standardized gap reservation solutions.

### Regulatory Basis and Core Considerations for UHPC Panel Gap Reservation UHPC (Ultra-High Performance Concrete), with its ultra-high strength and durability, is widely used in building curtain walls, landscape components, and other fields. Its joint gaps must simultaneously satisfy three core factors: material properties, thermal deformation, and construction tolerances. According to industry standards such as the "General Technical Conditions for Non-Load-Bearing UHPC Components" (Plan No. 2024-0232T-JC), combined with Qinglong's experience from over a thousand projects, **the recommended gap width is 5-10mm under normal conditions**, while regions with special climates require dynamic adjustment through thermal calculations.

Gap reservation requires key consideration of: ① Thermal deformation: UHPC has a thermal expansion coefficient of approximately 10×10⁻⁶/℃, and expansion must be calculated based on the local annual temperature range (e.g., -30℃ to 40℃ in northern regions); ② Installation tolerances: factory prefabrication precision (±2mm) and on-site hoisting deviations need to be buffered by the gaps; ③ Waterproofing requirements: exposed components require weather-resistant sealant embedded in the gaps, as insufficient width can easily cause the sealant layer to tear. For more industry information: +WeChat qlfsbl123

### Construction Recommendations for Gap Reservation in Different Scenarios **1. Exterior Wall Cladding and Curtain Wall Systems** For UHPC exterior wall panels used in commercial complexes and landmark buildings, a combined scheme of "5mm base gap + 2mm adjustment gap" is recommended. In the Century Plaza renovation project on Nanjing East Road, Qinglong used BIM technology to simulate thermal stress and precisely controlled the gaps of translucent UHPC panels at 6mm, satisfying formal continuity while preventing panel surface cracking caused by thermal expansion and contraction. For curved or irregularly shaped components, an additional 1-2mm gap is required to accommodate three-dimensional spatial tolerances.

**2. Landscape and Interior Decoration** For non-load-bearing components such as landscape benches and flower beds, gaps may be appropriately reduced to 3-5mm, but the joint filler material must match the UHPC color. In the Dongguan Women and Children's Activity Center project, Qinglong used GRC and UHPC composite components, achieving delicate joints for European-style moldings with a 4mm gap combined with elastic sealing strips. When interior GRG ceilings connect to UHPC walls, the gaps must be designed according to acoustic requirements, typically reserved at 8mm and filled with sound-absorbing cotton.

**3. Adaptation Adjustments for Extreme Environments** In severely cold regions (such as Northeast China) or hot and humid environments (such as South China), gap widths need to be corrected through thermal calculations. For example, in a municipal project in Harbin, Qinglong's technical team enlarged the gaps of UHPC bridge decorative panels to 12mm based on a temperature range of -35℃ to 30℃, and used cold-resistant silicone sealant to ensure a service life of over 15 years. Overseas projects, such as a UHPC curtain wall at a Malaysian airport, must consider the impact of typhoon loads on gap stability, adopting a combined scheme of metal connectors and elastic joints.

### Qinglong's Full-Chain Service Ensures Gap Construction Quality As a national high-tech enterprise and participant in UHPC standard development, Qinglong gets involved in gap scheme planning from the detailed design stage: ① Using Rhino parametric design to optimize joint layouts and reduce on-site cutting; ② Using dedicated molds during factory prefabrication to control panel edge flatness (tolerance ≤1mm); ③ Using 3D laser scanning for positioning during construction to ensure gap uniformity. From material R&D to after-sales maintenance, Qinglong upholds the philosophy of "meticulous attention to detail and constant pursuit of excellence," providing customers with full-process technical support from gap reservation to final forming, helping achieve the perfect unity of architectural aesthetics and structural safety. For more industry information: +WeChat qlfsbl123