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The damage of expansion joints is a common problem of bridges, which adversely affects not only driving comfort and safety but also the durability of the structure. Jointless bridges can fundamentally solve this fragile problem. However, how to accurately assess its environmental and economic benefits has not been studied, specifically as climate change intensifies. To address these issues, this study first examines the effects of climate change on design expansion allowance of bridge expansion joints based on climate projections. Subsequently, the life-cycle environmental and economic benefits of two jointless bridges located in Beijing–Hong Kong–Macau Expressway are quantified under climate change scenarios. Moreover, uncertainty and random forest algorithm-based importance analyses are carried out to help decision-makers identify major environmental and economic factors and develop eco-friendly plans to facilitate jointless bridge construction. Results indicate the following: (1) the design expansion allowance of bridge expansion joints tends to increase with the time-dependent temperature and humidity; (2) the avoidance of traffic detours caused by the maintenance and replacement of expansion joints is a major source of life-cycle environmental and economic benefits; (3) traffic detour distance is the most important factor influencing the life-cycle environmental and economic benefits. [ABSTRACT FROM AUTHOR]

Energy consumption and pollutant emissions from buildings have caused serious impacts on the environment. Currently, research on building environmental costs is quite insufficient. Based on life cycle inventory of building materials, fossil fuel and electricity power, a calculating model for environmental costs during different stages is presented. A single-objective optimization model is generated by converting environmental impact into environmental cost, with the same unit with direct cost. Two residential buildings, one located in Beijing and another in Xiamen, China, are taken as the case studies and analyzed to test the proposed model. Moreover, data uncertainty and sensitivity analysis of key parameters, including the discount rate and the unit virtual abatement costs of pollutants, are also conducted. The analysis results show that the environmental cost accounts for about 16% of direct cost. The environmental degradation cost accounts for about 70% of the total environmental cost. According to the probabilistic uncertainty analysis results, the coefficient of variation of material production stage is the largest. The sensitivity analysis results indicate that the unit virtual abatement cost of CO2 has the largest influence on the final environmental cost. [ABSTRACT FROM AUTHOR]

China's building industry urgently needs to accelerate the deployment of zero-carbon building technologies and zero-carbon project practices to facilitate the net-zero target. This study aims to explore the application potential and benefits of applying low-carbon technologies in existing buildings from a life-cycle perspective to drive zero-carbon building retrofits in China. To illustrate the impacts of the application of low-carbon technologies on zero-carbon building retrofitting, the mitigation values and abatement costs were evaluated for 16 typical low-carbon technologies of buildings, and the comprehensive incremental benefits model considering the environmental, economic and social impacts was developed. The incremental cost-effectiveness ratio index with the time value was proposed to explain the feasibility of building zero-carbon retrofit for different levels of technology application. In this study, a public building (kindergarten) in Beijing was taken as a study case, and the initial life-cycle energy consumption and carbon emissions based energy simulation were considered as the benchmark to compare the effect of zero-carbon transformation of the case building with different degrees of technology application. It is found that the economic benefit of implementing zero-carbon retrofitting of the case building through these low-carbon technologies increases from 42% to 66%, while the environmental benefit decreases from 57% to 32%. The analysis of incremental cost-effectiveness ratio indicates that achieving zero-carbon renovation over the lifetime of the kindergarten is economically feasible, and the comprehensive incremental benefits of the application of low-carbon technologies will exceed the incremental cost. The quantitative research for building low-carbon technologies in this study might provide an effective assistance on technology selection at the project level for better zero-carbon renovation strategies. • Mitigation value and abatement cost of 16 typical building LCTs were quantified • Application of LCTs notably affects cost and benefits in design and operation stages • Traditional heating electrification and photovoltaic contribute the most carbon reduction • Incremental cost-effectiveness ratio of building improves with deeper application of LCTs [ABSTRACT FROM AUTHOR]