Study On The Seismic Collapse-Resistance Capacity Of Corroded RC Frame Structures

To improve the seismic collapse safety is the focus and core of performance-basedseismic design thoughts. Buildings should have enough security stock to avoidstructural collapse destruction under rare earthquake and mega earthquake. Corrosion isthe most important factors in the structural seismic performance degradation, whichleads to steel bar cross-sectional area reduction, mechanical properties degradation, andbonding properties degradation between reinforced and concrete, etc.. Based onincremental dynamic analysis (IDA) in this paper,6different corrosion extent of RCframe structures for anti-collapse fragility are analyzed, the structural seismiccollapse-resistant capacity under rare earthquake and mega earthquake, and collapsesecurity stock are researched in the influence of different degree of steel bar corrosion.Firstly, the effect of corrosion on the structural seismic performance is consideredfrom the point of the corroded reinforced constitutive, its mechanism, influencingfactors and research methods are researched, the degradation rule of its mechanicalproperties is revealed, finally the corroded reinforced constitutive model is established;Secondly, the key issues involved in IDA are discussed, the ground motion recorded,ground motion intensity indicators Sa(T1,5%) and structural response indicators θmaxareestablished; Finally, the collapse performance points defined in the IDA curve are usedfor structure collapse judgment criteria, and CMR put forward by Applied TechnologyCouncil in the USA is used for the quantitative indicator of structural seismiccollapse-resistant capacity, and then the seismic collapse-resistance capacity of corrodedRC frame structures is researched.The results show that the collapse criteria can more accurately and reasonablyreflect the actual structure collapse situation; with the increase in the rate of steel corrosion, the probability of collapse under rare earthquake and mega earthquake alsoincreases, and the growth rate is becoming more and more big, but the CMR is less;when steel corrosion rate is in the range of0%to15%, the seismic collapse-resistancecapacity under rare earthquake can meet the requirements, but when steel corrosion rateis more than10%, the seismic collapse-resistance capacity under mega earthquake andsecurity stock can not meet the requirements. This research can provide the referencefor the seismic performance assessment of existing RC frame structures influenced bysteel corrosion.