When External Prestressing Strengthening Is Suitable / 什么情况下适合体外预应力加固

External prestressing is useful for existing beams, bridges, parking structures and industrial buildings with load increase, deflection risk, cracking or limited demolition conditions. 体外预应力适合承载提升、挠度控制、裂缝控制和不便大拆改的既有梁、桥梁、停车楼和工业建筑。

Suitable Structures / 适用结构

Existing beams, bridges, parking structures and industrial floors may benefit when capacity, crack control or serviceability is insufficient, especially when demolition is difficult. 既有梁、桥梁、停车楼和工业楼盖在承载、裂缝或使用性能不足，且不宜大拆改时可优先考虑。

When It Is Not Suitable / 不适合的情况

External prestressing is not a universal solution. If anchorage zones are weak, access is impossible, corrosion protection cannot be maintained or the load path is unclear, strengthening must be reconsidered. 体外预应力不是万能方案。如果锚固区薄弱、无法施工、长期防腐无法保证或传力路径不清，应重新判断加固路线。

Key Review Points / 关键复核点

Anchorage zone capacity, deviator layout, tendon path, jacking access, local strengthening, vibration, fire protection and long-term corrosion protection must be reviewed together. 锚固区承载、转向块、钢束路径、张拉空间、局部补强、振动、防火和长期防腐必须一起复核。

Delivery Logic / 交付逻辑

The first deliverable should be a strengthening concept and risk note, before detailed drawings or construction. This avoids spending money on a scheme that cannot be built. 首先应形成加固概念和风险意见，再进入详图和施工，避免先做出一套现场无法实施的方案。