The test platform, composed of components such as a superconducting magnet, Dewar, and cryogenic system can realize the force-thermal-electrical-magnetic multi-field testing of superconductors, in which the superconducting magnet functions to provide a background magnetic field. The split low-temperature superconducting magnet can generate a uniform transverse magnetic field at the center, and its semi-open structure provides convenience and large space for testing. The split low-temperature superconducting magnets operate in low-temperature, strong magnetic fields, and high-current environments, verifying the structure and performance of split low-temperature superconducting magnets is necessary because these conditions can cause the complex electromagnetic forces, thermal stresses, and assembly forces they carry to deteriorate the magnets’ electromagnetic performance and stability. The dynamic winding process of superconducting coils, as well as the excitation and cooling processes of the coil assembly, were experimentally studied in the research applying wireless strain testing method and using techniques like cryogenic strain gauges, cryogenic thermal sensors, and Hall plates. The findings demonstrate that the strain accumulated in the coils during dynamic winding is approximately linear with the number of winding layers and falls back slightly with time, and the strain of the coil assembly and the surrounding magnetic field in energized conditions have a high synchronization with the excitation current, the properties of the superconducting magnet testing and processing procedures can be efficiently revealed by the strain evolution law inside the coil.

Prestressed concrete structures are subject to environmental corrosion during service, resulting in corrosion of the reinforcement and varying degrees of damage to the structure. This leads to a reduction in the structural load carrying capacity. To investigate the effect of the reinforcement corrosion on the flexural performance of prestressed concrete beams, corroded prestressed concrete beams were tested by a four-point bending test. It is shown that the corrosion of the ordinary reinforcement has a small effect on the cracking strength and ultimate strength of test beams. However, the effect of corrosion on the yield load is more obvious. When the corrosion rate of ordinary steel reinforcement is 3.8%, the yield load of the test beams decreases by 15.6%. Additionally, the corrosion rate of steel reinforcement has a smaller effect on the yield deflection of the test beams, but the effect on the ultimate deflection is more obvious. When the corrosion rate of steel reinforcement is 11.5%, the ultimate deflection decreases by 8.6%. The corrosion of the prestressed steel strand has a significant effect on the cracking load and yield load of the test beams, which is the main factor affecting the load carrying capacity and deformation capacity of the prestressed beams. The cracking load of the test specimen decreases by 32.9% when the strand corrosion rate is 7.6%.

To investigate the effect of different cooling methods on the uniaxial compressive properties of ultra-high performance concrete (UHPC) after high temperature, 45 specimens with the dimension of 100 mm×100 mm×300 mm were designed and fabricated. The cooling methods and heating temperature were chosen as test variable parameters. Observe the apparent characteristics, quality loss, and failure mode were observed after different high temperatures and cooling methods. The variation law of compressive strength was analyzed. The experimental results show that as the temperature increases, the surface cracks increase. The mass loss rate increases under different cooling methods. A higher mass loss rate occurs under natural cooling with the same temperature. Under natural cooling, the mass loss rate increases rapidly at first and then slowly. An approximately linear increase is presented under water cooling. The compressive strength shows a trend of first slightly increasing and then decreasing. Compared with the normal temperature, with the temperature increase, the maximum compressive strength increased by 18.3% and 13.4% respectively under natural cooling and water cooling. When the temperature reaches 800 ℃, the compressive strength under natural cooling and water cooling decreases to 20.8% and 18.8% of compressive strength at normal temperature, respectively. When the temperature exceeds 600 ℃, the axial deformation ability of blocks is significantly enhanced. Compared with natural cooling, the peak strain under water cooling develops rapidly, but tends to be consistent at 800 ℃. The peak strain under natural cooling and water cooling increases to 2.22 times and 2.24 times the peak strain under normal temperature conditions, respectively. Compared with natural cooling, the elastic modulus under water cooling is relatively small and undergoes three stages: slow decrease, fast decrease, and slow decrease. Based on the experiments, a formula for calculating the residual strength of UHPC after water cooling is proposed, which can provide a basis for evaluating the load-bearing capacity of a building after fire.