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Cables are the main load-bearing components of cable-stayed Bridges. The durability and reliability of cables are directly related to the safe operation and service life of the whole bridge. Aiming at the problem of cable detection and maintenance, a new type of cable detection robot is designed in this paper. To further enhance the stability of the robot, the structure adopts symmetrical arrangement to make the center of mass of the robot system coincide with the cable axis. According to the working condition of the robot, a flexible body spring that meets the parameter requirements is designed, which not only meets the required preload, but also meets the starting torque of the motor. The robot is simple in structure, standardized in parts, easy to assemble and disassemble, and has good obstacle clearance ability and detection efficiency.

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The combustion characteristics of ammonia/hydrogen premixed laminar flow and the effect of hydrogen on the combustion performance of ammonia fuel were studied. First, the corresponding model of ammonia/ hydrogen premixed laminar combustion is established by using GRI3.0 mechanism, Konnov mechanism, Mei mechanism, Okafor mechanism, and Otomo mechanism respectively. Second, the simulation results are compared with the experimental results. It is found that the Mei mechanism and Okafor mechanism are more suitable for ammonia/ hydrogen premixed laminar combustion. On this basis, the effects of equivalent ratio, hydrogen ratio, and initial temperature on laminar flame velocity, maximum combustion temperature, and NO mole fraction were studied. The results show that the laminar flame velocity, the maximum combustion temperature, and the mole fraction of NO first increase and then decrease with the increase of the equivalent ratio, and the laminar flame velocity reaches the maximum when the equivalent ratio is 1.1. At the same time, with the increase of hydrogen ratio and initial temperature, the maximum combustion temperature increases first and then decreases. The mole fraction of NO increased with the increase of hydrogen ratio and initial temperature. The results show that mixing hydrogen in ammonia can improve the combustion characteristics of ammonia.

In order to know the relation between the bending and temperature of coated steel beam in fire test, the authors carried out a certain amount of fire tests for coated steel beams. Through the analysis of testing data it can be seen that the bending and temperature of coated steel beam are closely related, and the time when the bending at the mid-span of the beam exceeds L 2 /400d mm is almost the same as that when the average temperature of the beam rises to 538 under the condition that the beam is subjected to a total load which represents 60 % of the design moment resistance.