Dynamic modeling of stock and flow in an urban residential building system: A case study of Beijing

Accumulation and renovation of ground buildings are the typical characteristics and inevitable results of the urbanization process. The resources and environmental pressure associated with energy and material flows between the urban building system and hinterland environment make building system a hot issue in the field of urban metabolism research. Systematic modeling of urban building flow-stock dynamics and related resources and environmental response are of great significance for macro-management such as urban spatial planning, urban resource management, and waste disposal. Using Beijing as the case city, we established a dynamic model for stock and flow of the urban residential building system with the STELLA modeling platform. The dynamic interval between the demand for steel and amount of demolition waste generated under different management scenarios was quantitatively simulated. The simulation results are as follows; ( 1 ) In the baseline scenario, the construction flow of residential buildings in Beijing increased rapidly, reaching a peak of 30.24 million m" in 2005; the demolition flow will peak in around 2057, with a demolition floor area of 20.73 million m". The highest value of the urban residential building stock will appear around 2075 , with an area of 751 million m∗. ( 2) If the per capita floor area reaches 45 m", the total steel demand will increase by 32.52 million tons in the next SI years (2019- 2100) ; if the lifespan of residential buildings is prolonged to the design lifetime, the total steel demand will decrease by 30.23 million tons in the same period. (3) In the baseline scenario, large-area scenario, and long lifespan scenario, the peak value of demolition waste is 0.029 billion tons, 0.039 billion tons, and 0.020 billion tons, respectively. These results shed light for policy makers to take prompt action and improve reuse and treatment levels of building demolition waste in the future.