周  威^1,2，张格明¹，郑文忠¹，  刘  铁¹
（1 哈尔滨工业大学土木工程学院； 2 哈尔滨工业大学材料科学与工程学院，哈尔滨150090）

[摘要]  某综合楼层2顶无粘结预应力混凝土双向板在张拉预应力筋时，发生了局部区域混凝土掀起的施工质量事故，分析表明是由张拉时该区域板混凝土实际强度过低所致。采用了放松板中被掀起区无粘结筋、凿除松动混凝土面层、重新浇筑较设计强度等级高一级的混凝土、再重新张拉无粘结筋加固处理方法。利用施工现场实际条件对加固后的无粘结预应力板进行了荷载试验，取得了板挠度实测结果。应用双向板带叠加法取得了变形的理论计算值，实测值与理论值吻合良好。加固后的预应力板满足相关标准中正常使用和承载能力极限状态要求，可验收使用。
[关键词]  无粘结；预应力；楼板；混凝土掀起；加固；检测

Detecting analysis and treatment of unbonded prestressed concrete slab with raising concrete region
Zhou Wei^1,2, Zhang Geming¹, Zheng Wenzhong¹, Liu Tie¹
(l School of Civil Engineering, Harbin Institute of Technology; 2 School of Material and Engineering, Harbin Institute of Technology, Harbin 150090, China)
   
Abstract: During tensioning unbonded tendons in construction, partially region of concrete was raising on a prestressed concrete two-way slab of a complex building. It is result of low strength concrete in this region.  Reinforcement method is that prestressing tendons were released in rainsing region, cracked concrete was taken out, higher strength concrete than design strength was renewing, moreover, released tendons were tensioned again. To inspect result of reinforcement, loading experiment was carried out on this unbonded prestressed concrete slab using material of practical construction scene. Actual deflections of testing center-span of this slab were measured under external load. Theoretic deflection of center-span was calculated by using method of two-way plane band splicing.  Calculation values are well accorded with test result. Two limits of load-bearing capacity and service of this slab after reirforcement meet with relative standard. So, it can be checked and accepted.
Keywords: unbonded; prestressed; slab; raising concrete: reinforcement; detecting