In order to study the influence law of northern acid rain on mechanical properties of concrete-filled steel tubular members , it is necessary to study the change law of mechanical properties of steel tube with different corrosion degree under acid rain corrosion condition. Hence, referring to the chemical composition of acid rain statistics over the years in Dalian City, the method of indoor accelerated corrosion with artificially prepared simulation acid rain solution was used to carry out monotonic tensile test on Q235 steel. Results showed that rust pits were easy to form on the steel surface after acid rain corrosion. The fracture of tensile coupons with low corrosion rate (β ≤ 10%) was mainly normal fracture failure, while the fracture of tensile coupons with high corrosion rate (25% ≥ β ≥ 15%) was mainly oblique fracture failure. Meanwhile, the yield strength, elastic modulus, ultimate strength, and elongation percentage of steel afterempirical acid rain corrosion decreased with the increase of corrosion rate, while Poisson’s ratio increased with the increase of corrosion rate. Based on the test data, the simplified empirical calculation formula of the mechanical properties index of Q235 steel under the condition of simulated acid rain corrosion condition was regressed, which could provide theoretical basis and scientific basis for the design and structural safety assessment of concrete-filled steel tubular composite structure in acid rain area.
