钻孔法检测在役混凝土梁残余预应力技术研究

Residual prestressing detection technology of in-service concrete beams by hole-drilling method

为保证码头作业的安全,利用钻孔法测量了某在役预应力轨道梁梁底测点处的混凝土应变。根据物理关系计算了梁底现存应力,当检测出现应变片粘贴角度发生偏差时,采用修正系数的方法对采集到的应变计算梁底现存应力,取梁底应力的平均值。建立了考虑钢筋应力输出和混凝土压应力的有限元模型。根据有限元分析的结果,通过线性回归方法建立钢筋应力和梁底中心混凝土压应力的关系,计算出在役混凝土轨道梁的残余预应力,并与按规范法计算出的残余预应力进行比较。比较分析结果表明测量结果合理有效,具有较好的适用性和实用性。

In order to ensure the wharf operational security,the concrete strain at the bottom measuring point of the in-service prestressed concrete beam was measured by hole-drilling method.The extant stress at beam bottom was calculated according to the physical relations.So the strain was gathered during detection when the stickup angles of strain gauge changed.Through correcting factors,the extant stress at beam bottom and the average value were computed.The finite element model considering the reinforcement stress output and the concretes compressive stress was established.Based on the analysis result,the relationship between the reinforcement stress and the concretes compressive stress at beam bottom center was built by the linear regression method.Therefore,the residual stress of in-service prestressed concrete beam was calculated.The comparison between the measurement result and the result calculated according to code shows that the measurement result has better applicability and practicability.