核电站有粘结预应力钢束预应力损失的监测技术研究

MONITORING TECHNOLOGY OF PRESTRESS LOSS OF BONDED PRESTRESSED TENDONS FOR NUCLEAR POWER PLANTS

根据CAN/CSA-N287.7-96《加拿大重水铀反应堆核电厂混凝土安全壳结构的在役检查和试验要求》的推荐制作两根标准试验梁,一根为有粘结预应力系统,一根为无粘结预应力系统,进行长期预应力损失监测、承载力试验和一系列的材料性能试验,对比两种试验梁的预应力损失规律,估算预应力损失,验证混凝土的收缩、徐变、预应力钢束的松弛等因素在实际的预应力损失中的比重。试验结果表明:由后张法建立的预应力系统,有粘与无粘的预应力损失规律相似,孔道灌浆对预应力的影响不大,主要起到对钢绞线的保护作用,锚固作用不明显;无论有粘无粘,预应力都由端部锚垫板对梁的轴向压力形成,预应力的传力方式非常相似;通过对本次试验的大量监测数据进行分析,用监测无粘结钢束的预应力损失间接反映有粘结钢束的预应力损失的方法是可行的。

According to the 'In-Service Examination and Testing Requairement for Concrete Containment Structures for CANDU Nuclear Power Plants'(CAN/CSA-N287.7-96),two test beams are designed,one is prestressed concrete with bond,the other is prestressed concrete without bond,a long term observation of the prestressing losses,static test and material performance test are carried out,the regularity of the prestressing losses of the two test beams is compared,the loss is estimated,it is verified that the effects of the shrinkage,creep,relaxation and other factors on the actual losses.The results show that the regularity of the prestressing losses between the concrete without bond and the one with bond system is similar,it is possible to use the long term observation of the prestressing losses of the concrete without bond system to reflect indirectly the prestress loss of the one with bond system.