Analysis Of The Performance Of RC Structures Progressive Collapse Resistance Considering Reinforcement Corrosion

Although the progressive collapse of a building structure is a small probability event,it has become the focus of public opinion due to the catastrophic loss of life and property.At present,most of the results on structural progressive collapse resistance do not consider the problems of structural durability damage and service performance degradation,and it is difficult to reveal the degradation law of structural progressive collapse resistance for buildings in long-term service.Therefore,this study takes reinforced concrete(RC)frame structures with reinforcement corrosion as the object of study and compares and analyses the effect of the degree of reinforcement corrosion on the remaining structural vertical load capacity.Based on this research objective,this study carries out a proposed static test study of the RC frame substructure with failed central columns due to reinforcement corrosion,a parametric analysis using numerical simulation methods,and a theoretical derivation of the residual structural load carrying capacity of the substructure.The main research contents and conclusions are as follows:(1)Five single-storey two-span 1/3 scaled-down RC frame sub-structure specimens were fabricated,one sub-structure model was used as a comparison specimen without treatment,and the other four were set at different levels of corrosion rates using electrochemical corrosion to investigate the mechanism of the effect of reinforcement corrosion on the load carrying capacity of the members;the design of the members took into account the horizontal continuous restraint effect and out-of-plane restraint effect at the end of the frame beam,and the material properties of each material of the specimens were determined.(2)Using vertical displacement loading control,the load-displacement relationship curve of the specimen,horizontal load and damage mode of the specimen can be obtained,through the test results to analyse and discuss the impact of reinforcement corrosion on the damage mode and bearing capacity of the frame substructure,the test results show that the damage mode of the reinforcement corrosion specimen is basically the same as that of the uncorroded specimen,still mainly in the span and beam end reinforcement pull off,but the reinforcement corrosion However,the corrosion of the reinforcement caused a reduction in the cross-sectional area of the reinforcement and a reduction in the strength of the concrete,resulting in a reduction in the ductility of the specimens and a failure of the suspension line mechanism to achieve the expected strength.(3)According to the material properties of the test specimens,the corresponding material ontology model was selected and a refined model of the RC frame substructure considering reinforcement corrosion was established based on ABAQUS,and on the basis of verifying the validity of the finite element model,the influence of reinforcement corrosion on the collapse damage mode and force progressive collapse mechanism of the model was analysed.In addition,the effects of different beam end boundary conditions,different concrete strengths and different span height ratios were also analysed.(4)For the assessment of the collapse resistance of RC frame substructures considering reinforcement corrosion,the theoretical formulation of the specimens under the compressive arch action is proposed through some basic assumptions and elastic theory calculations,and the correctness of the theoretical model is verified through calculations.The calculation results show that the theoretical method can effectively reflect the actual load carrying capacity of RC frame substructures considering reinforcement corrosion in the compressive arch action.