Abstract:In view of the disadvantages of traditional force sensors in monitoring the stress of bridge cable, such as inconvenient installation, low test accuracy, brittleness and low ultimate strain of bare fiber grating sensors, a fiber grating intelligent fiber composite sensor (GFRP-OFBGS) was developed to monitor the stress of bridge cable by packaging fiber grating sensors with high durability and high strength glass fiber. Firstly, the processing technology of GFRP-OFBGS and its layout method in bridge cable are given, so that GFRP-OFBGS can co-deform with bridge cable. According to different layout methods, two kinds of self-monitoring intelligent cable, adhesive type and replacement type, are developed. Then, the sensing characteristics of GFRP-OFBGS with different diameters are studied. It is concluded that the strain sensitivity coefficient of bare fiber grating is not changed after it is packaged with FRP, and the temperature sensitivity coefficient is increased by 1.7 times. The ultimate strain increases with the increase of the diameter of GFRP-OFBGS. Secondly, two kinds of self-monitoring intelligent cable are tested respectively. The test results can well characterize the whole tensioning process and tensile force. Finally, the technology of GFRP-OFBG sensor in arch bridge tie rod layout is explored, and it has been implemented and applied in the construction of arch bridge tie rod in Dadu River, Ebian, Sichuan, and the whole tensional process of tie rod has been monitored successfully. Based on the monitoring data of one year, the tensile effect of tie bar is tested and the current operating condition is judged.

Abstract:In this paper, a one-stretch calculation method for multi-stage prestressed space grid structure is presented. The prestress value of the i prestressed bar in a certain stage is taken as the unknown, and the prestress criterion equation is established and solved by structural mechanics method. Then we can calculate the control value of each prestressed rod i times in this stage (including the original internal force value of each prestressed rod), the influence value of post-tensioned prestressed stress on the pre-tensioned prestressed stress, and the internal force and node displacement of the struts of the grid structure until the last time of prestressing in this stage. The final internal force control value, internal force and joint displacement of the prestressed bar of the multi-stage prestressed grid structure can be obtained by repeating this analysis and calculation. With this method, the internal force value of the prestressed rod does not need to be adjusted in the process of prestressed tension, and the operation process of prestressed application can be completed at one time. An example is given to illustrate that the calculation results show that the proposed method is correct, reliable and effective.

Abstract:Based on the research of domestic and international standards and codes of cable system, the commonness and difference of these standards and codes are studied from the aspects of fatigue performance of cable body base material, fatigue performance and watertight performance of prestressed tendon-cable anchor assembly. Based on the comparison of the performance requirements of the cable system and the interpretation of the anti-corrosion requirements of the cable system in the international standard, the gap between the Chinese standard and the international standard is found out. Based on the design, manufacture, inspection, installation and maintenance of the cable system, the rationality and operability of the relevant provisions in each specification are analyzed, and some thoughts on the implementation or revision of these standards are put forward.

Abstract:Generally, epoxy gripping type is used for overall anti-slip of cable in cable-stayed Bridges with low towers, but this device cannot realize anti-slip of single strand and single cable change. The cross-key anti-slip device is proposed to study its application in low tower cable-stayed Bridges. Through finite element analysis, anti-slip force test, fatigue life and layout study, it can be seen that the anti-slip key can reliably hold the steel strand, has sufficient anti-slip ability and good anti-fatigue property, and adopts the cross-layout form to solve the problem of anti-slip and single cable replacement of a single steel strand. The tensioning process of the cross anti-slip key was summarized and perfected according to the simulated tensioning process test, and it was successfully applied in Fenhe Bridge in Linfen, Shanxi Province.

Abstract:In view of the common problems of poor waterproof performance and easy corrosion of tie rods, the anti-corrosion tie rods are designed. Its reliability is verified by watertight test and durability test, and its application in Jialing River Bridge in Nanchong Lower Zhongba is introduced. The test and application results show that the tie rod has the advantages of safety, reliability and excellent anti-corrosion performance.

Abstract:This paper introduces the new combined extrusion cable structure and its application in Pumiao Bridge, and the construction method of the whole bridge boom replacement. Through the use of mobile hoist system, the replacement construction of boom is safer and more convenient, and the construction speed is significantly improved. This law is the first of its kind in China.

Abstract:Configuration software refers to some special software for data acquisition and process control, which can realize the role of equipment monitoring and control. In modern industrial system, configuration software is widely used in power system, water supply system, petroleum, chemical industry and other fields. In the control of special mechanical equipment, configuration software and PLC technology also play an important role. This scheme takes the combination of Asia Control Company's KingView6.53 software and OMRONCJ series PLC as an example to explain in detail how configuration technology is applied in a large upgrading project.