Simulation Research On Assembly Building Policy In Nanjing Based On System Dynamics

With the development of economy and the continuous improvement of the urbanization rate,China's construction industry has also developed rapidly.The traditional cast-in-place production method has not conformed to China's green sustainable and healthy development concept.As the government continues to promote the industrialization of buildings,the advantages of fabricated production methods are gradually becoming obvious.In 2016,the General Office of the State Council"Opinions on the Development of Prefabricated Buildings" made detailed instructions on the development of prefabricated buildings,and strived to make the proportion of fabricated buildings in new buildings reach 30%within 10 years.However,due to the limit of the economic development level of each region and the government's policy support,the development level of prefabricated buildings in different provinces and cities is different.As the first demonstration city of prefabricated buildings in Nanjing,the government has promoted the development of prefabricated buildings by formulating relevant support policies.Therefore,it has important practical significance for the analysis and study of the effect of the prefabricated building support policies in Nanjing.The paper sorts out theories and related research on building industrialization,public policy and system dynamics,and combs the current research on fabricated buildings and research methods for policy effect analysis.This paper uses the system dynamics method to study the effect of the prefabricated building policy in Nanjing.Firstly,it analyzes the development status of prefabricated buildings in Nanjing,sorts out relevant policies,and qualitatively analyzes the impact mechanism of various policies on prefabricated buildings.Secondly,it analyzes the influencing factors of prefabricated building development from five aspects:policy,economy,architecture,technology and environment to study the causal relationship between various factors;Thirdly,determine the feedback relationship between the system boundary of the prefabricated building policy simulation system model and the various elements of the system,establish a causal loop diagram and stock flow graph,and determine the structural equation and model parameters.The validity of the model is tested.Finally,the future development trend of the prefabricated building in Nanjing is predicted through the prefabricated building policy simulation model.Through the model simulation,the development of the prefabricated building in Nanjing is compared under the policy of different prefabricated building-related policy changes.The changes are analyzed in detail,and the conclusions are drawn based on the results of the simulation,and the policy recommendations for the development of prefabricated buildings in Nanjing are proposed.Based on the above research results,the conclusions are:fiscal policy,financial policy,taxation policy,land policy,planning policy,technical policy and construction support policy in Nanjing have crucial role in upgrading the growth of fabricated buildings;the impacts and influences of prefabricated buildings based on different policy pairs are different.Fiscal policies,financial policies,and technical policies have the best effect on improving the demand for fabricated buildings.For increasing the supply of fabricated buildings and improving the installed buildings,the technical policies is the best;the technical policy has the greatest effect on reducing carbon emissions.In this regard,the Nanjing Municipal Government should adjust the focus of the prefabricated building policy,from the aspect of increasing consumer incentive policies to expanding the prefabricated construction market;enhancing corporate incentive policies,increasing the supply of fabricated buildings;improving technical support policies,and building green and healthy buildings to promote the development of fabricated buildings.