Analysis Of Progressive Collapse Performance Of RC Structures Considering Steel Corrosion

The initial local damages can cause disproportional damage to the structure and cause the progressive collapse.In the available studies related to progressive collapse of RC structures,the corrosion effects have been ignored.Actually,the corrosion of steel bars can reduce the structural performance,although it has not been paid enough attention.In light of this,this thesis conducts a comprehensive study on the progressive collapse performance of corroded RC structures.The main contents are summarized as following:(1)The corrosion-induced deterioration parameters of structures and the corresponding physical models are summarized.The model uncertainties are highlighted.The OpenSees software is used to establish the FEM of the intact RC beam-column subassembly for progressive collapse analysis.The reliability of the FEM is validated by the test data.Then the effects of model uncertainty for the corrosion-induced deterioration parameters on the collapse performance of RC structures have been carefully examined.(2)Through a parametric study,the effects of multiple parameters,i.e.,corrosion rate,span-to-depth ratio and steel strength,on the progressive collapse performance of corroded RC structures have been investigated.The peak load and the ultimate load have been identified from the static pushdown curves as the indicators of progressive collapse capacity of structure.The corrosion-induced deduction ratios for the peak load and the ultimate load are calculated further to measure the influence level due to corrosion for the RC structures.By a sensitivity study,the effects of the above parameters on the collapse performance of corroded RC structures have been examined.The prediction models of the corrosion-induced deduction ratios on peak load,ultimate load and peak displacement have been derived.(3)Based on the energy-balance method,the static pushdown curves of the corroded RC structure are transformed to the dynamic response curve for progressive collapse.The dynamic response coefficients of the peak load and the ultimate load are determined on the dynamic response curve.Then the prediction models of the dynamic response coefficients of the peak load and the ultimate load are generated.(4)The OpenSees model that is developed in content(1)for progressive collapse analysis of the corroded RC structure is further improved by considering the distributed uncertainty of the corrosion in the reinforced steel bars.The effects of the distributed uncertainty of corrosion on the progressive collapse performance of RC buildings are further investigated.