中文摘要：

以某岛外引水渡槽桁架为工程背景,提出了采用预应力与外包水泥基灌注料对钢筋混凝土桁架下弦杆进行加固的方法,并采用分级加载的试验方法,在加固后的桁架上进行了原位静载试验,测试了桁架主要控制截面在各级荷载作用下的挠度、应变（应力）等数值变化,将测试结果与有限元软件计算结果进行比较分析,研究了桁架加固后的力学性能.试验结果表明,预应力与外包水泥基灌注料加固桁架能够较大程度地提高桁架结构承载力,且新增结构层与原结构共同工作及变形协调较好,加固效果较为理想.

英文摘要：

Based on the engineering background of an island water diversion aqueducts truss, this paper put forward a method using prestressed force and outsourcing cement filling material to strengthen the bottom chord of reinforced concrete truss, used the hierarchical load test method to carry out in-situ static load experiment on the strengthened truss, tests deflection, strain（stress） value and their changes of the main control section of truss at different levels of loads, made a comparative analysis of the test results, calculated the value of finite element method, and obtained the mechanical performance of the truss after reinforcement. The experimental results show that the use of prestressed force and outsourcing cement filling material to strengthen truss can improve the bearing capacity of truss structures to a great extent, and new structural layers can work with the original structural layers and their deformation coordination is good. The reinforcement effect is also ideal.