Research On Life Cycle Carbon Emissions Calculation Of Long-span Suspension Bridges In Mountainous Areas

With the rapid development of China’s economy,the scale and quantity of public transport infrastructure construction has also been increasing with the time goes by.In particular,bridge projects as an important part of the road,the number and volume are increasing all the time.As a special engineering product,the scale of the bridge project is generally large,the consumption of labor,material consumption and machinery is huge as well.Moreover,the bridge project has a complex structure and a long life cycle,which will produce a large amount of greenhouse gas emissions in the whole life cycle of the bridge.The suspension of the development of China started very late,but since China’s first modern suspension bridge Shantouwan Bridge is completed,China has built a number of large-span suspension bridge over 1000 meters.There have been few studies on carbon emission accounting for suspension bridges at home and abroad for a long time,but the demand for materials and mechanical equipment for suspension bridges,especially gravity-type anchor base suspension bridges,during construction and construction is extremely high,and the impact of greenhouse gas emissions on the atmospheric environment can not be ignored.It can be seen that the study of establishing a carbon emission accounting model for the life cycle of a suspension bridge is of great significance for energy conservation and emission reduction in the field of large-span suspension bridges in mountainous areas.On the one hand,based on the simplified carbon emission accounting model in this paper,the design drawings can be used to realize the quantitative budget of carbon emissions in the life cycle of the suspension bridge.On the other hand,the research results of this study can be bridge selection and project decision-making and bidding to provide reference for environmental impact assessment.With the Chongqing Sunxi River Steel Truss Suspension Bridge as the project background,and based on the carbon emission factor and the suspension bridge carbon emission accounting model calculated above,the building materials preparation stage,section construction stage,operation and maintenance stage and suspension bridge demolition of the case project Systematic quantitative accounting of carbon emissions from the scrap phase.The calculation results show that:1.At each stage of the suspension bridge’s life cycle,the largest carbon emission is the building materials preparation stage.The proportion of carbon emissions in the whole life cycle is about 87%,including 89.3% of building materials production and 10.7% of building materials transportation.The second is the proportion of the operation and maintenance phase is about 8%;while the carbon emissions in the construction phase account for the smallest,accounting for only about 2% of the total carbon emissions.2.In the three parts of the suspension bridge anchor base base,cable tower and pier,and the upper structure of the main bridge,the carbon emissions of the whole life cycle carbon emissions of the sub-sections are the anchor bases,and the proportion of the whole bridge life cycle is reached,and it is about 47%.The carbon emissions generated during the life cycle of the tower and the abutment and the main structure of the main bridge are generally equally divided.3.The total amount of GHG emissions generated during the life cycle of the case suspension bridge is as high as 207,000 tons,which exceeds the total carbon emissions of concrete continuous beam bridges and steel-concrete continuous beam bridges studied by other scholars.The comparative analysis found that although the total carbon emission of the suspension bridge is large,the carbon emission law of each stage is basically consistent with the carbon emission law of other concrete and other bridge types studied by other scholars.4.Based on the research results,it can be found that the carbon emissions generated during the construction phase of the suspension bridge(building materials are preparation and construction stages)are very large,accounting for about 89%.Based on this,this paper conducts a preliminary study on the carbon emission control measures during the construction stage of the suspension bridge,and proposes a theoretical system for the whole process of carbon emission control of the suspension bridge based on the whole process control idea and PDCA cycle framework.To control the carbon emissions of the suspension bridge,it is important to grasp the carbon emission control of the production and transportation of building materials.The control of carbon emissions from building materials production can be improved by improving the process and selecting alternative products that produce less carbon emissions.The carbon emissions generated by controlling building materials transportation can be discussed with logistics optimization as an entry point.During the construction of the suspension bridge,it is possible to focus on controlling the carbon emissions of the anchor base.In order to achieve better control results,we should conduct carbon emission comparisons in stages from the perspective of carbon emission process control,and clarify the control effect of carbon emissions and the next carbon emission control targets.