How to Select UHPC Strengthening Components for Old Building Renovation?

In the renovation of old buildings, the selection of UHPC reinforcement components must follow four major principles: "force matching, space adaptation, durability compatibility, and construction convenience". The core is to select the corresponding type based on reinforcement needs (flexural, compressive, seismic, and crack resistance), original structural conditions, and construction space constraints. Qinglong provides customized reinforcement component selection solutions, which have been successfully applied to multiple old building renovation projects with remarkable reinforcement results.

1. Selection by Reinforcement Needs: Precisely Matching Force Characteristics

Different reinforcement objectives correspond to different types of UHPC components. Flexural reinforcement: use UHPC reinforcement strips (thickness 20-30mm, width 100-200mm) or ultra-thin UHPC panels (thickness 15-25mm), bonded to the tensile zone at the bottom of beams and slabs. Qinglong's flexural reinforcement of beams in an old factory building adopted 25mm thick UHPC reinforcement strips, increasing flexural capacity by more than 40%. Compressive reinforcement: use UHPC hoops (cross-section dimensions customized according to column diameter) or UHPC wrapping layers (thickness 30-50mm) to enhance the compressive strength and stability of columns and walls. Qinglong's compressive reinforcement of columns in an old office building adopted 40mm thick UHPC hoops, increasing compressive capacity by 50%. Seismic reinforcement: use UHPC seismic joint components (such as joint outer sleeves and seismic connectors) or UHPC shear wall panels (thickness 40-60mm) to enhance structural ductility and energy dissipation capacity. Qinglong's seismic reinforcement of an old residential building adopted 50mm thick UHPC shear wall panels, raising the seismic grade by 1 level. Crack resistance reinforcement: use UHPC thin-layer repair components (thickness 10-15mm) or UHPC crack sealing strips to repair existing cracks and prevent their propagation. Qinglong's crack resistance reinforcement of an old bridge deck adopted a 12mm thick UHPC thin layer, achieving a 100% crack closure rate.

2. Selection by Original Structure and Space Conditions: Adapting to Renovation Constraints

Old building renovation must take into account both the original structural characteristics and the construction space. Original structure type: bonded UHPC components (reinforcement strips, thin panels) are preferred for concrete structures; welded UHPC components (outer sleeves, connectors) are preferred for steel structures; wrapping UHPC components (hoops, wall panels) are preferred for masonry structures. Qinglong's old concrete factory building adopted bonded UHPC reinforcement strips, requiring no modification to the original structure during construction. Construction space constraints: for narrow spaces (such as inside suspended ceilings and beam-column joints), use ultra-thin, lightweight UHPC components (thickness ≤25mm, weight ≤60kg/m²). Qinglong's basement beam reinforcement adopted 20mm thick ultra-thin UHPC panels to adapt to the narrow construction space. Appearance preservation needs: when the original building appearance needs to be preserved, use UHPC components matching the color and texture of the original materials. Qinglong's old heritage-style building renovation adopted brick-patterned UHPC reinforcement panels, with an appearance consistent with the original brick walls.

3. Selection by Durability and Construction Convenience: Ensuring Long-Term Stability and Efficiency

Selection must take into account both post-renovation durability and construction feasibility. Durability compatibility: match the durability of the original structure; for outdoor or corrosive environments, use corrosion-resistant UHPC components (with mineral admixtures and stainless steel fibers). Qinglong's coastal old building renovation adopted corrosion-resistant UHPC reinforcement components, with a chloride ion penetration coefficient ≤1.0×10⁻¹²m²/s. Construction convenience: preferentially use factory-prefabricated, on-site assembled UHPC components to reduce on-site wet work. The prefabrication rate of UHPC components in Qinglong's old building renovation reached 100%, improving on-site installation efficiency by 50%. Schedule adaptation: for projects with tight schedules, use rapid-hardening UHPC components (strength reaching 80% of the design strength within 7 days). Qinglong's emergency renovation project adopted rapid-hardening UHPC reinforcement strips, shortening the construction period by 30%.