Corrosion Behavior Of Steel-wood Connections In Chloride Environment

Wood structures have the advantages of adjusting the relative humidity of the environment,heat preservation and energy saving,acid and alkali resistance,and high salt environment,etc.,and are increasingly used in various harsh environments,such as the coastal boardwalk,swimming pool.The large chloride ion concentration in offshore buildings and swimming pools will aggravate the corrosion rate of steel connectors in wooden structures,and then affect the durability of the structure.In this paper,according to the different types of steel-wood connection and chloride ion concentration environments,salt spray corrosion tests of wood-steel clamping connection and slot-in steel plate connection under 1%,3%,and 5% sodium chloride concentrations were conducted.The relationship of the corrosion depth versus Chloride ion concentration and duration of corrosion cycles was studied.By setting up a contrast test group,the corrosion rules in the steel plates of the wood-steel clamping connection and slot-in steel plate connection versus air containing chloride ions,Pinus sylvestris var Glulam,preservative treated Glulm were compared.Minimal corrosion of steel plate found in slot-in steel plate connection.The TANALITH? E(CA-C)copperazole preservative in Glulam can mitigate the corrosion of steel plate in the steel-wood connection in salt spraying environment.The rust layer is advantageous to mitigate continued corrosion of the steel plate.The corrosion of steel plate in the steel-wood connection under different chloride ion concentrations was simulated.The simulation results correspond well with the test results,which proves the feasibility of the model and can be used to predict the corrosion of steel plates in steel-wood connection under other chloride ion concentrations.The environmental design spectrum method was used to calculate the time-equivalent of salt spraying test and a typical humid and hot marine atmosphere in a certain area.Under salt spraying test conditions of 1%,3%,and 5% Na Cl concentration,the corrosion of connection experienced 21 days,16.3 days,and 15 days,respectively is approximately equivalent to that outdoor exposured one year in the region's typical hot and humid ocean atmosphere.Furthermore,the long-term corrosion performance of steel-wood connection was predicted,and the corrosion results of steel plates equivalent to 10 years in atmospheric corrosion are obtained.The mechanical properties of steel-wood connections considering corrosion were studied.The mechanical properties of the steel plate after corrosion were reduced,and the bearing capacity of the steel clamping connection considering corrosion was simulated.In the finite element model,the porous elastic model and the Drucker-Prager plastic model was used in the constitutive relationship for the wood.The finite element analysis was carried out by considering only the thickness loss caused by the corrosion of the steel plate,and the both of thickness loss and the property degradation of the steel plate.The failure mode by finite element simulation is close to the theoretical result.The bearing capacity of connection results were compared and analyzed.The reduction coefficient for considering the influence of steel plate corrosion on the bearing capacity of connection derived according to the Johansen pin connection was obtained.