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由于PC桥齿板结构的突变型和受力的非线性,不容易计算其出受力区域及大小,应用声发射技术对张拉中的齿板进行实时定位监测。中高强度混凝土的室内压剪和拉伸试验中,存在明显的平静期和活跃期,进入活跃期后,声发射能量计数和振铃计数指数增加。参考声发射能量计数和振铃计数的相关性,优选第3通道和总的参数数据。通过对声发射参数统计和声发射源定位,齿板混凝土受力未达到峰值强度的65%并且内部没裂缝出现,确定齿板张拉过程是安全的。同时,本次齿板张拉监测也会为D区预应力混凝土构件的安全评价提供一定参考。
Due to the sudden change and force non-linearity of PC bridge tooth plate structure, it is not easy to calculate the area and size of its force-bearing area. Acoustic emission technique is used to monitor the tooth plate in tension during real-time positioning. There are obvious periods of calm and active during the indoor compression-shear and tensile tests of medium and high strength concrete. After entering the active phase, the acoustic emission energy count and ring counting index increase. With reference to the correlation between acoustic emission energy count and ring count, channel 3 and overall parameter data are preferred. Through the statistics of acoustic emission parameters and the location of acoustic emission source, the stress of the toothed slab does not reach 65% of the peak strength and no internal cracks appear, so it is safe to determine the tooth plate tension. At the same time, the tooth plate tension monitoring will also provide some reference for the safety assessment of prestressed concrete members in zone D.