浅谈橡胶管制孔增生孔道摩阻的原因及消减方法

重点介绍了采用橡胶管预埋和抽拔制孔工艺，引发后张钢筋混凝土梁“管道偏离设计位置”等增大孔道摩阻的原因探寻，并提出了以“加强制孔胶管本身的质量控制和质量保证”等方法来消减孔道摩阻的工法改进。对解决后张法预应力砼梁的张拉预应力损失问题，保证后张法预应力砼梁的制造质量，提高后张法预应力砼梁的抗载能力具有重要的意义。

Discussion on the Causes of Friction Increase Owing to Use of Rubber Pipe to Form Post-tension Beam Duct and Decreasing Measures

This article mainly introduced how the technology of forming the post tension duct by using pre-embedded rubber pipe for post tension R. C beam caused the increasing friction in the duct and what measures should be taken to solve these problems. The causes include deviation of duct position from design, the duct is not smooth and straight in straight section, the left and right side at mid section of the parabolic cure duct is not symmetrical or displacement is incurred, rough duct surface or the duct is of smaller diameter due to poor quality of rubber pipe surface or insufficient size of rubber duct, and removal of rubber duct at wrong time, improper use or control of pre-embedded parts, tensioning equipment, grouting tools and tensioning method. The measures to solve those problems include enhancing quality control of the rubber pipe ; guarantee reinforcement binding quality and reinforcement cage rigidity, enhancing control of reinforcement cage and verticality of girder during casting process, avoiding displacement of girder segment, strictly following tensioning procedure and method and control tensioning quality. The technology improvement in this way is of great significance to solve the problem of prestress loss, guarantee beam quality and improve the beam＇ s bearing capacity.