26
D0I:10.7672/sgjs2014180026
施工技术
CONSTRUCTION TECHNOLOGY
既有无黏结预应力混凝土楼盖改造
钢绞线重锚施工技术* 陈浩，刘玉辉，陈维超，黄伟（1.湖南省建筑工程集团总公司，湖南长沙410004：
2.湖南省建设工程质量安全监督管理总站，湖南长沙410116）
2014年9月下第43卷第18期
【摘要】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错具，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错固，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。
【关键词】混凝土；既有建筑；预应力；钢绞线；改造；重锚；施工技术
［中图分类号］TU757
【文献标识码］A
【文章编号】1002-8498（2014)18-0026-05
Construction of Strand AgainAnchorage for Concrete PrestressedFloorReconstructionwithUnbondedTendons
Chen Hao',Liu Yuhui?,Chen Weichao',Huang Wei'
(1. Hu'nan Construction Engineering Group Corporation,Changsha,Hu'nan410004, China; 2.Hu'nan Central Station of Safety Supervision and Management for Construction Engineering, Changsha,Hu' nan 410116, China)
Abstract : 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.
Key words: concrete; anchorage ; construction
0引言
existing
building；
随着国民经济的快速发展、技术的进步、城市
规划的目新月异，许多既有建筑物为满定城市建设发展或新的使用要求，需要在已建的预应力楼盖上开洞或对部分结构物进行拆除，以增大局部层高，
*湖南省住房和城乡建设厅科学技术基金项目（KY201419）
【作者简介】陈浩，研究员级高级工程师，副总经理，总工程师，E-mail : wlrwe@ 163. con
【收稿日期】2014-02-11
prestressing;
strand;
reconstruction;
again
或增设自动扶梯、竖向电梯，或满足城市规划需要等，为此需在施工中截断横穿洞口的无黏结预应力筋。
传统的楼盖开洞改造遵循开洞、预应力筋截断、二次张拉等工序，在截断预应力筋时由于预应力的释放，有可能便楼板在改造施工期间的抗裂，挠曲性能不能满足原设计要求，在实际荷载作用下也有可能出现裂缝。为使无黏结预应力筋在截断时保持原有结构的整体刚度与抗裂性，采用开口锚