为满足朔黄铁路T梁提载要求，针对桥梁的特点和构造，采用新型体外预应力体系对其进行强化加固。该体系的锚具、预应力束和转向器均与普通体外预应力不同，预应力损失不能直接按现行规范进行计算。通过24 m足尺梁张拉试验，利用IMC数据采集系统动态记录体外预应力筋在张拉过程中有效应力的整个变化过程，简捷准确地获取了新型体外预应力体系锚固损失、摩擦损失的试验数据。研究结果表明：体外预应力锚固损失为0．98％σcon，摩擦损失为1．6％σcon，摩擦因数μ为0．063。试验结果为该新型预应力体系的设计和施工提供了有效计算依据，也为今后改善体外预应力结构体系提供了参考。%In order to meet the requirements of T bridge for increasing load on the Shuohuang railroad,a new type of external prestress system was adopted to strengthen the bridge according to its characteristics and forma-tion.The anchorage,prestressed tendons and steering gear of the new system were different from common exter-nal prestress system,so the loss of prestress can not be directly calculated according to the current specification. The IMC system was utilized to record the whole process of the change of effective stress in external prestressed reinforcement and all data of anchoring loss,friction loss was obtained accurately and quickly.The experimental results show that,a full-scale beam of 24 m span reveals that the anchoring loss is 0.98%,the friction loss is 1.6% with the friction coefficient equal to 0.063.The test results not only provide a reference for this new sys-tem and also afford a basis for improving the design of the external prestressed structure in the future.
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