To detect the stress of steel structures and members using the existing magnetism, a magnetic stress sensing system integrating a magnetic flux induction coil, a magnetic flux measurement device, a loaded device, and data acquisition software was developed. The magnetic coupling test research was carried out for different grades of structural building and bridge steel specimens to establish the magnetic stress flux mathematical model, and the fitting equation of the magnetic flux changes with the positions of different sections of specimens was analyzed. Furthermore, a practical formula for stress detection was obtained through the experiments. Meanwhile, on these bases, the typical steel truss structure model of a Bailey beam was designed and manufactured under different working conditions, nondestructive online stress testing was carried out, and the stress of the model structure and its members was measured by strain and magnetic flux tests to obtain the curves of the test results for the stress–strain and magnetic stress flux, respectively. The results of these two methods are in good agreement with each other. The stress of the steel truss model structure was analyzed and calculated using the finite element method. The results agreed well with the experimental results from the magnetic stress sensing system—the maximum error was about 5%, which meets the requirements of engineering applications.

Lattice beam and prestressed anchor rod are used to enhance stability and prevent failure of soil or rock slopes. In this study, a model of Lattice beam and prestressed anchor rod (LBPAR) system was designed with reinforcement mechanisms and a model test was constructed with a circular slip surface of a loess slope. First, interaction between the loess slope and the LBPAR system was investigated by an LBPAR system analysis model. Stability of sliding mass from the sliding bed with an arc-shaped sliding surface was then studied by an experimental model designed. Finally, internal force distribution of lattice beams in the LBPAR system was investigated by using a large-scale physical model test. The results were compared to those calculated using the reverse beam method, indicating that the LBPAR system strengthened the sliding mass in space and improved the overall stability of the loess slope. With vertical loading, the axial tensile stress of the main anchor rod increases continuously. The bending area of the anchor rod was concentrated within 2 m of the sliding surface. And the maximum bending moment reaches 70 N·m. The sliding mass was subject to vertical load pressure, lattice beams’ pressure, and dead weight in the meantime and the maximum earth pressure value is near the node of the lattice beams. It is proved that such a method excels in the engineering design of loess landslides, which has promising applications in the future.

Inherent magnetism is an important properties of ferromagnetic materials. In this study, the internal magnetic field intensity (IMFI) and internal magneto-mechanical effect (IMME) of Q390B in a structural field were investigated to detect and verify the inherent magnetism in structural settings. In the IMFI test, the magnetic flux was used to detect the change in magnetic field to verify the existence of magnetism. In the IMME test, a novel instrument was implemented to measure the magnetic variation in the Q390B specimen without magnetic flux. Based on the low frequency cyclic (LFC) tensile loading tests, the inherent magnetism was fully described. Experimental results indicate that IMME shows great potential and more efficiency in inherent magnetism studies and can be promoted in the near future.

Damage of high-strength bolt (DHSB) is inevitable during long-term use. Such damage is irreversible that may not be replaced in time, and the potential danger is proven by the changes of the mechanical properties of DHSB. To investigate the mechanical properties of DHSB, this paper uses the software ABAQUS to simulate the stress of various types of DHSB under earthquake, and compares with undamaged high-strength bolts (UDHSB). The results show that the most unfavorable position of the crack is at the bottom of the second ring thread. The model with shorter crack length will have greater stress concentration and displacement deformation. The more the number of cracks, the greater the concentrated stress value. The concentrated stress generated by the tooth deformation is at the top of the thread tooth, and the concentrated stress generated by the crack is at the bottom of the thread tooth. Changing the tooth shape in the appropriate position is beneficial to reduce the degree of bolt damage. Bolt damage will double the harm, and timely replacement of damaged bolts is very time-sensitive and necessary.