The shear behavior of corroded reinforced concrete (RC) members is an urgent problem to be solved. The study carried out an experimental program on the shear behavior of 21 beams, which included 3 un-corroded RC beams and 18 corroded ones. Both shear span-to-depth ratio and corrosion degree influencing the shear strength as well as failure patterns were discussed in detail. This paper aims to contribute to a better understanding about the effect of corrosion on the shear behavior of corroded RC beams. The test results show that corrosion of stirrups reduces the aggregate interlock capacity of concrete, also the ductility and shear strength of the flexural members. In shear-compression zone, cracks caused by corrosion of stirrup have a predominant influence on shear strength; Failure modes of RC beams depend largely on shear span-to-depth ratio and are little affected by corrosion of stirrups. Based on the results of experiments and the limit equilibrium theory, the calculation model of shear capacity for corroded simply supported RC beams is proposed, which has a simple form and clearly physical conception.

To investigate the flexural behavior of corroded steel beams strengthened by carbon fiber reinforced polymer (CFRP) plate, flexural test of five steel beams were carried out. The effects of corrosion and prestressing force levels on the flexural capacity, failure modes and interfacial stress were investigated. Meanwhile, considering the corrosion surface the calculation method of flexural capacity of corroded beams strengthened by CFRP plate was also established. The results showed that failure modes of corroded beams were the fracture of the CFRP plate after the shear failure of interface on the mid-span and fracture location of CFRP plate was mostly at the loading point. The rough surface of the corroded steel can enhance the efficiency of stress transfer at the interface, thereby improving the effective bond length of the interface. The shear stress was mainly concentrated on the CFRP plate end, and peak value appeared at the loading point. Compared the reference beam, the ultimate flexural capacity of the corroded beam strengthened by CFRP plate with 15% prestress level increased at a ratio of 21%, and utilization ratio of the CFRP plates was up to 71.59%.

To investigate the degradation law of the mechanical properties of corroded steel, the standard specimens from machining steel members in service for 9 years in an industrial environment were subjected to tensile tests. The influences of different degrees and types of corrosion on the fracture path, stress-strain curve, and mechanical properties of specimens were discussed. Finally, the damage constitutive model of corroded steel was established based on the damage mechanics theory. The results showed that the failure modes of corroded specimens were related to the degrees and types of corrosion. The fracture morphology of specimens with general corrosion were step-like and the fractures of steel were uneven. However, those with local corrosion were mainly flat-like, and the fracture path was along the cross section where the larger corrosion pits were located. The fracture path of the specimen was related to the interaction of the corroded surface and internal material defects (holes). Meanwhile, with the increase of corrosion degree, the yield platform of stress-strain curve gradually became shorter, or even disappeared, and the ultimate strain and elongation at break decreased, implying that the ductility of steel became worse. Ultimately, the good agreement between the curves of the model and test indicated that the damage model could reflect the damage development process of corroded steel in the tensile process better. Corrosion damage resulted in the decrease in the damage threshold, and the damage variable D decreased by the time fracture occurred and the maximum reduction rate was up to 62.5%.

Concerns have been raised about both the disinfection and the reusability of respiratory protective equipment following a disinfection process. Currently, there is little data available on the effects of disinfection and decontamination on positive pressure respiratory protective hoods (PPRPH). In this study, we evaluated the effect of vaporized hydrogen peroxide (VHP) on the disinfection of PPRPH to determine applicability of this method for disinfection of protective equipment, especially protective equipment with an electric supply system.