How to Select UHPC Strengthening Components in Old Building Renovation? Selection Principles and Matching Solutions Explained

In old building renovation, the selection of UHPC reinforcement components requires comprehensive judgment based on the building's current condition, reinforcement needs, and service environment. Proper selection can precisely resolve structural defects and improve building safety and durability. Clarifying the core selection principles and applicable scenarios is key to the success of renovation projects. Drawing on practices from multiple renovation projects, Qinglong analyzes the core selection points.

1. Reinforcement Demand-Oriented Principle: Precisely Match Defect Types

Selection should center on reinforcement needs, choosing appropriate UHPC components for different structural defects. Flexural reinforcement needs: when the flexural strength of building beams and slabs is insufficient, UHPC reinforcement plates and strips are used to enhance the cross-section's flexural capacity through bonding or anchoring. In a beam reinforcement project at an old factory building, Qinglong used 20mm-thick UHPC reinforcement plates, increasing flexural bearing capacity by more than 40%. Shear reinforcement needs: when the shear performance of columns and walls is insufficient, UHPC wrapping jackets and shear stirrups are used to enhance shear capacity, suitable for old building reinforcement in seismic zones. Crack repair reinforcement: when components have cracks, UHPC repair blocks and grouting material are used, combined with carbon fiber fabric for coordinated reinforcement to stop crack propagation. In a crack repair project at an old office building, Qinglong achieved effective crack control through UHPC grouting material filling + reinforcement plate covering. Load-bearing capacity improvement needs: when the overall structure's bearing capacity is insufficient, load-bearing components such as UHPC support columns and joists are used to replace or supplement original components, suitable for structural upgrades of aging buildings.

2. Structural Compatibility Principle: Adapting to Original Building Characteristics

UHPC reinforcement components must be compatible with the original building structure to avoid secondary risks. Material compatibility: ensure reliable bonding between UHPC and original concrete, masonry, and other materials; use special interface agents to enhance bond strength. Qinglong's special interface agent has a bond strength of ≥3MPa, meeting reinforcement requirements. Stiffness matching: the elastic modulus of UHPC components should match the original components (around 2.8×10⁵MPa) to avoid stress concentration caused by excessive stiffness differences. For old masonry structure reinforcement, lightweight UHPC components can be used to reduce additional loads. Dimensional adaptation: based on building space and existing component dimensions, use thin, miniaturized UHPC components to minimize impact on usable building space. Qinglong's thin UHPC reinforcement plates can be as thin as 15mm, suitable for reinforcement in confined spaces. Construction compatibility: select UHPC components that are easy to construct, such as prefabricated reinforcement plates and modular components, to reduce on-site wet work and shorten construction periods, accommodating the construction constraints of old building renovation.

3. Environmental Adaptation Principle: Addressing Complex Service Scenarios

Select UHPC reinforcement components with appropriate weather resistance based on the old building's service environment. Indoor dry environments: use conventional UHPC reinforcement components without additional anti-corrosion treatment. Outdoor open-air environments: use weather-resistant UHPC components with fluorocarbon coatings applied to the surface to enhance UV and rain erosion resistance. In an exterior wall reinforcement project at an old teaching building, Qinglong used weather-resistant UHPC components with a service life of over 30 years. Coastal high-salt-spray environments: use anti-corrosion UHPC components with rust inhibitors added, paired with stainless steel connectors to prevent salt spray corrosion, suitable for old building renovation in coastal areas. High-temperature and high-humidity environments: use high-temperature resistant and moisture-proof UHPC components, optimizing the mix ratio to improve heat and humidity resistance and prevent component performance degradation.

4. Economy and Feasibility Principle: Balancing Cost and Effect

Selection must balance economy and construction feasibility to achieve optimal value. Component reusability: choose modular, adjustable UHPC reinforcement components to improve reusability and reduce costs; Qinglong's series of reinforcement components can accommodate various size requirements. Construction difficulty control: prioritize prefabricated components to reduce on-site processing, lowering construction difficulty and costs; prefabricated UHPC reinforcement plates cost about 20% less than cast-in-place alternatives. Long-term cost considerations: select based on maintenance needs, choosing highly durable UHPC components with long maintenance intervals to reduce later maintenance costs, offering greater advantages in whole life-cycle cost accounting. Compliance verification: ensure selected UHPC reinforcement components comply with industry standards such as the "Technical Specification for Application of Ultra-High Performance Concrete"; all of Qinglong's reinforcement components pass third-party testing and meet the acceptance requirements of renovation projects. Through multi-dimensional selection considerations, Qinglong provides precise UHPC reinforcement solutions for old building renovation, achieving structural safety upgrades and optimized functionality.