Research on the Seismic Performance of Concrete Compressed‐Flexural Members After Cumulative Damage From 100 Years of Design Usage

This study investigates the long‐term effects of cumulative damage on concrete members over a century, emphasizing its critical inclusion in design protocols. Employing both static and dynamic experimental approaches, the research first examines the fundamental mechanical properties of damaged concrete at the material level. Earthquake intensity data from Northeast China are then analyzed to establish the frequency of predominant intensities over a 100‐year timeframe. Subsequently, four frame columns are exposed to cumulative pseudodynamic seismic damage, followed by pseudostatic testing to assess their seismic resistance. The results demonstrate that repeated sub‐cracking‐stress damage increases concrete's uniaxial compressive strength while reducing its ultimate deformation capacity. For elements with a low axial load ratio, minor seismic damage minimally impacts ultimate deformation but enhances ultimate bearing capacity, with the steel reinforcement reaching yield at an earlier stage. In contrast, for elements with a high axial load ratio, minor seismic damage has negligible effects on both ultimate deformation and bearing capacity, though it still accelerates the onset of yield in the steel reinforcement.