Multi-Level Carbon Emission Hotspot Identification and Low-Carbon Optimization of Teaching Buildings Based on BIM Technology

Taking a reinforced-concrete frame teaching building at a university as a case study, this study established a carbon emission accounting framework based on BIM-derived quantities, identified carbon emission hotspots at the stage, material, and component levels, and comprehensively evaluated the accounting results and emission reduction potential through sensitivity analysis, Monte Carlo uncertainty analysis, and low-carbon scenario assessment. The results showed that the total A1–A5 carbon emissions of the case-study building were 16,812.69 tCO2e, corresponding to a carbon emission intensity of 442.51 kgCO2e/m2, of which modules A1–A3 accounted for 94.40%. C35 concrete, reinforcing steel, and autoclaved aerated concrete blocks collectively contributed 88.1% of A1–A3 emissions, while reinforcing steel, infill walls, and floor slabs constituted the major component-level hotspots. Monte Carlo simulation showed that the baseline accounting result fell within the main probability distribution range, while the integrated optimization scenario reduced total A1–A5 carbon emissions by 7.72%. This study quantified carbon emissions from the building material production, transportation, and construction stages (A1–A5) of a teaching building and identified priority targets for emission reduction. The results provide a quantitative basis for low-carbon material selection, key component control, and construction-stage optimization of teaching buildings in China.