Study On Evolution Of Construction Stock And Its Driving Factors In Beijing

Construction stock is the material accumulation in urban construction activities,which is accompanied by the consumption,accumulation and emission of a large number of resources and energy,and provides services for development of social and economy.The increase of demand for construction material stock caused by economic and demographic factors may lead to dual pressures of resources and environment,and then restrict the sustainable development of cities.In the past two decades,the urban area of Beijing has expanded rapidly,the population has grown steadily,the urbanization process has been remarkable,and the corresponding material stocks of building and infrastructure have undergone great changes,putting tremendous pressure on resources and the environment.Therefore,it is necessary to quantify the construction stock,analyze and understand its accumulation process and mechanism.This will help to assess the resource and environmental pressures of the evolution of Beijing’s construction stock,and it will be useful for solving resource and environmental problems and promoting sustainable urban development.Based on the material flow analysis framework and bottom-up method,this paper constructs a construction material stock calculation model,dynamically quantifies the stock of 10 materials in the 6 types of constructions in Beijing from 1992 to 2016.Secondly,builds a stock-driven model,calculates and analyzes the material flow and resource environment effects of the construction stock system in Beijing;Finally,the LMDI method under the IPAT model was used to analyze the driving factors and influence factors affecting the changes of Beijing’s construction stock.The research results are as follows:(1)Beijing’s construction stocks are on the rise in 1992-2016.By 2016,the total construction stocks expanded to 4.91 times in 1992 to reach 2001.91 Mt.It experienced a slow growth in 1992-2000,a rapid growth in 2000-2008,and a steady growth in 2008-2016.(2)The input of materials increased from 34,146,700 tons in 1992 to 10,852,700 tons in 2016,and the consumption of building resources in Beijing is on the rise.According to the construction points,the input of building materials is the most,followed by roads,pipelines and rails.According to the material,the input of sand and gravel is the most in the past years,and the input of steel has obvious improvement trend.The material output increased from 9,419,600 tons in 1992 to 3,805,900 tons in 2016,and construction waste in Beijing has a growing trend.According to the construction points,the sum of material output of road materials over the years is the most,followed by buildings,followed by pipelines and rails.According to the material points,the output of sand and gravel is the highest in the past years,and the output of steel and cement is also large.Considering the recycling effect,the resource effect and environmental effect of Beijing’s building stock evolution material metabolism are better than the resource environment effect under the uncirculated condition.(3)Looking at the whole period,from 1992 to 2016,Beijing’s population and economic growth have a positive impact on the increase of construction stocks,while technological upgrading has a restraining effect on construction stock growth.Improving the efficiency of stock utilization,reducing the intensity of material use,and improving construction technology can be regarded as the main strategy of reducing construction stocks.