Sustainability and Structural Integrity in Seismic Design: The Role of Reinforcement Ratios in Life Cycle Impact and Building Safety

The construction sector faces increasing pressure to decarbonize, as embodied emissions from structural materials often dominate the environmental footprint of reinforced concrete (RC) buildings. Although reinforcement ratios are key drivers of structural capacity, their environmental implications under seismic design remain insufficiently quantified. This study investigates the relationship between longitudinal reinforcement ratios and both seismic performance and life-cycle environmental impacts in RC frame buildings. Three code-compliant reinforcement configurations (1%, 3%, and 5%) were analyzed for three- and nine-story structures designed under Eurocode 8. Mechanical performance was evaluated using nonlinear pushover analysis, while embodied impacts were quantified through Life Cycle Impact Assessment (LCIA) using the ReCiPe 2016 midpoint and endpoint methods. Results show that increasing steel content reduces concrete volume and increases lateral capacity, but may significantly decrease ductility and increase environmental burdens. Optimal performance is achieved with moderate reinforcement ratios, which reduce embodied impacts while preserving seismic safety. Furthermore, reducing the amount of concrete while increasing the amount of steel reduces the weight of structures by between 19% (3 stories) and 22% (9 stories), improving their seismic resistance due to the reduction in seismic forces in areas of moderate seismicity. These findings demonstrate that reinforcement selection introduces a measurable trade-off between structural integrity and sustainability, providing designers with quantitative guidance for low- and medium-rise RC buildings in seismic regions.