Galfan-coated full-locked coil rope is widely applied in long-span spatial structures because of its high strength and lightweight. However, the corrosion problem is relatively serious in the natatorium, which affects the structure’s durability. To deeply reveal the corrosion mechanism of Galfan-coated cable, this study first measured the natatorium on-site, and the results indicated that the natatorium environment can be simulated by a constant temperature and humidity environment in engineering. Then, the constant temperature and humidity corrosion test was carried out to simulate the corrosion of Galfan-coated cable with a certain amount of chloride ions on the surface, and the early corrosion rate was obtained. Later, the neutral salt spray accelerated corrosion test was carried out to predict the corrosion rate of the cable in the natatorium environment in the middle and late periods. The specimens included no-stress unprotected coating cable, high-stress unprotected coating cable, and high-stress protected coating cable. The results show that high stress will accelerate the corrosion, and a protective coating can effectively prevent the corrosion. Finally, the linear model, bilinear model, and bilinear model considering chloride ion accumulation were proposed to study the corrosion of the Galfan coating. The results show that the linear model overestimates the corrosion rate, and the bilinear model and bilinear model considering chloride ion accumulation are practical. Meanwhile, corresponding maintenance suggestions were given for the natatorium project to improve the structure's durability.

An increasing number of large-span space structures use flexible roofs to achieve a light and splendid architectural effect. When a flexible structural system such as a cable net is applied in a large-span stadium, the roof will deform significantly under the self-weight and wind load. Accessory structures of the roof such as catwalks, radial drainage pipes, circular drainage channels, and radial cable trenches need to cooperate with the large deformation of the roof to prevent damage caused by the large deformation of the roof. To thoroughly unveil the analysis and design method of an accessory structure, this paper first carried out the wind tunnel test to determine the wind load of the structure. Then, the gust response factors of each roof area and the dynamic amplification coefficient of the accessory structure considering the roof vibration were determined. Next, circular and radial catwalks were designed based on static analysis. A sliding joint was set in the accessory structure to adapt to the large deformation of the roof. Finally, a time history analysis of the catwalk was carried out to obtain the maximum deformation value of the sliding joint for the safety of the structure. The results demonstrate that the maximum deformation is less than the value given by the design and meets the specification.

Concrete-filled steel tube (CFST) columns are widely used in civil engineering because of their excellent bearing capacity; however, the reinforcement of CFST columns lacks effective measures. To strengthen CFST columns quickly and effectively, two methods, namely, winding FRP (fiber reinforced polymer) or steel strips, were explored in this work. Two unconfined CFST columns, eight FRP-strengthened CFST columns and four welded steel strip-strengthened CFST columns were manufactured and tested. The failure modes and axial load–strain curves of all specimens under compression load were concluded and compared. The effects of the primary parameters, such as FRP layers (1, 2, 3 and 4 layers) and steel strip thickness (3.0 and 6.0 mm), on the bearing capacity and deformation capacity were also investigated. The ultimate load of CFST columns increased from 28.72 to 64.16% after being confined by FRP with one to four layers. The ultimate load of the welded steel strip-strengthened CFST column with 3.0 mm steel strips and 6.0 mm steel strips increased by 28.46% and 49.82%, respectively, compared with the unconfined CFST column. Thus, the increase in FRP layers and steel strip thickness can markedly improve the compressive behavior of the FRP/welded steel strip-strengthened CFST columns. The cost performance of the two different reinforcement methods also showed that the cost of the welded steel strip-strengthened CFST column is nearly 40% of that of the FRP-strengthened CFST column when the same strengthening effect was obtained, which indicated that the welded steel strip-strengthened CFST column is more cost-efficient than CFST columns confined by FRP. Finally, six existing models for the ultimate load of FRP-strengthened CFST columns were presented and evaluated. From the evaluation results, the Zhang et al.’s model, Lu et al.’s model and Hu et al.’s model for FRP-strengthened CFST columns were shown to provide the best applicability and accuracy. Based on the Mander et al.’s model, a model for the ultimate load of welded steel strip-strengthened CFST columns was proposed and evaluated. The proposed model can accurately predict the ultimate load of welded steel strip-strengthened CFST columns.