Target low-carbon conditional probability for low-carbon structural design

Abstract

Probabilistic low-carbon structural design is an emerging method for mitigating structural embodied carbon, whereas the absence of a rational target for probabilistic regulation hindered its effectiveness. Here, we clarify the necessity of verifying the low-carbon conditional probability in low-carbon design of structures/structural members, and propose methods for determining acceptable and optimal low-carbon conditional probabilities (i.e., P_LT,a and P_LT,o), respectively based on the carbon mitigation obligation for construction sector and the carbon-related cost minimization for structures/structural members. Based on typical levels of parameter values for target determination, we reveal that P_LT,a is primarily influenced by the distributions of structural embodied carbon premised on safety I_s and its embodied carbon limit I_cr,c, and it typically decreases with the decrease in the difference between the coefficients of variance of I_s and I_cr,c. The reduction of marginal cost for embodied carbon reduction (k), the increase of relative carbon cost (u_c), and the increase of penalty for the excess of carbon emissions (γ_p) facilitate the attainment of the lowest carbon-related cost at lower embodied carbon levels, where a higher P_LT,o could be specified to promote stricter carbon mitigation efforts. The target low-carbon conditional probability P_LT is recommended to be taken as the larger of P_LT,a and P_LT,o, while the γ_p required to ensure that the lowest carbon-related cost is reached with P_LT increases as k increases or u_c decreases.