既有无黏结预应力混凝土楼盖改造钢绞线重锚施工技术

Construction of Strand Again Anchorage for Concrete Prestressed Floor Reconstruction with Unbonded Tendons

以长沙汇源大厦裙楼部分拆除改造工程为对象,从现场试拆除试验、主体结构重锚端部加固梁、楼盖开洞、梳形锚垫板安装、开口式锚具安装、无黏结预应力钢绞线切断、现场监控等技术要点介绍了既有无黏结预应力混凝土楼盖改造钢绞线重锚施工关键技术。采用一种新型开口式钢绞线锚具,确保了拆除过程中的无黏结预应力筋的安全截断及可靠再锚固,使结构中被保留的预应力筋的应力不损失或损失很少,无需二次张拉。监控结果表明:在拆除改造过程中,楼板的应变、位移满足正常使用条件要求,整体结构也没出现倾斜现象,采用该技术确保了整体结构的安全性。工程实践结果表明,该方法取得了良好的效果。

Based on the dismantlement reconstruction engineering of partially podium building of Huiyuan building in Changsha, the technical points of field test on dismantlement, strengthening beam of again anchorage end region,opening in floors,comb anchor plate,open type anchor,blanking, monitoring of the key construction technology of strand again anchorage of concrete floor prestressed transformation with unbonded tendons were introduced. A new open strand anchor is used to ensure the safety blanking and reliable re-anchoring of unbonded tendons in the demolition process,the stress of preservation tendons is no loss or few losses without secondary tensioning. Monitoring results showed that the strain and displacement of floor met the requirements of normal using conditions in dismantlement reconstruction process,the inclined phenomenon of whole structure did not appear, the security of the whole structure was ensured with the technology. Engineering practice showed that this technology obtained a good effect.