| With the steel structures is widely used in society,many steel structures exposed to harsh environment for a long time will inevitably be corroded severely,even if protective and structural measures are both employed.The resultant corrosion pits on the steel structures will not only reduce the ductility and fracture toughness of steels,but also promote the initiation and propagation of a crack.Moreover,these can lead to stress concentration apparently raised in the local stress level,had a great harmful influence on earthquake resistance of steel beam-to-column connections.This paper takes the steel beam-to-column connections under the neutral salt spray environments as the research objects,by conducted a series of experimental investigations,and combined with theoretical analysis and numerical simulations,revealed the influence of earthquake resistance of corroded steel beam-to-column connections.The research results are for the earthquake resistance of corroded steel beam-to-column connections to provide technical support and theoretical basis of assessment.In this paper,the research work includes the following aspects:(1)Through the method of outdoor complex automatic neutral salt spray cycle accelerated corrosion of Q235 steel beam-to-column connections,these are corroded for eight months.(2)Based on cutting from the corroded steel beam-to-column connections plate processing standard test pieces,with the help of PS50 three-dimensional scanners,different time corroded steel surface test pieces partial scan were scanned,and had a statistical analysis of scan data,and obtained specimen surface morphology andcorrosion pits size variation with time of the corrosion;At the same time,through the DNS 300 electronic universal testing machine,the twelve test pieces were tested about the tensile,analyzed failure modes and mechanical properties,stress-strain relationship curve in different with the extent of corrosion.(3)Based on a beam-to-column connection and three corroded steel beam-to-column connections under cyclic load performance test,the hysteretic behavior of beam-to-column connection were obtained,through the dates,the relationship of the hysteresis curve,energy dissipation capacity,bearing capacity,ductility factor,stiffness,deformation and failure modes with the extent of corrosion were analyzed,and revealed the earthquake resistance degradation mechanisms node about the corroded steel beam-to-column connections.Through the finite element simulation,the earthquake resistance of steel beam-to-column connections were analyzed,and obtained effect of uniform corrosion and local corrosion of the earthquake resistance of beam-column connections,and revealed degradation mechanisms about earthquake resistance of the corroded steel beam-to-column connections. |
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