Study On Evaluation Of Precast Concrete Structure’s Assembly Scheme From The Angle Of Eco-efficiency

With the continuous deterioration of the global ecological environment and the continuous expansion of the construction demand,it has become a necessary way to develop precast buildings to improve the level of construction industrialization and promote the green development of buildings.Compared with cast-in-place buildings,the precast buildings are more highlighted in the time efficiency,energy efficiency and environmental efficiency.However,the precast buildings with different assembly levels is different in eco-efficiency because of the differences in the design of assembly schemes.From the perspective of the whole industry chain,this paper puts forward the eco-efficiency evaluation of the precast buildings under different assembly schemes,and further promotes the research on the sustainable development of the precast buildings.First of all,the relevant contents and theories are analyzed in eco-efficiency evaluation of the assembly schemes and the assembly scheme has been preliminarily formulated in this paper.Through the connotation and application of eco-efficiency theory,the eco-efficiency assessment is introduced into precast buildings and converted into products’ value research created by the unit impact of the environment.In view of two aspects of value and environmental impact,the idea of value engineering is used to divide the value part into building function and construction cost,and the carbon footprint theory is used to measure the environmental impact with the carbon footprint level.Finally,the eco-efficiency evaluation of the assembly scheme will be translated into three dimensions,which are architectural function,construction cost and carbon footprint.In order to highlight the eco-efficiency of building direct production process,the materialization stage is selected as the scope of the index analysis.In addition,based on the latest provisions of the evaluation criteria of precast buildings and the system types which are commonly used in China’s precast building demonstration projects,the components have been selected which are commonly used under the prefabricated shear wall structural system,and the common assembly schemes are formulated for the structural system.Then,based on these three dimensions,this paper separately constructs the architectural function measurement model,cost measurement model and carbon footprint measurement model.In order to better analyze and evaluate the indicators of the three dimensions,in the architectural function measurement model,the AHP is used to determine the weight of architectural function evaluation index system,and the expert scoring method is used to score the function index of each assembly scheme.The function scores and coefficients can be determined.In the construction cost measurement model,the cost indicator range is defined,and the LCC method is used to analyze the direct cost in materialization stage to obtain the value of cost and coefficient under different schemes.In the carbon footprint measurement model,the analysis scope of carbon footprint is defined,and the Process-Based LCA method is used to elaborate the carbon source path in the materialization phase to obtain the carbon footprint levels and coefficients under different schemes.The eco-efficiency evaluation model is constructed using functional coefficients,cost coefficients and carbon footprint coefficients.The eco-efficiency is comprehensively analyzed and compared by the index ratio method of the assembly schemes.Finally,combining with the example of precast building project,four assembly schemes which meet the requirements are selected for analysis,and the functional coefficients,cost coefficients,and carbon footprint coefficients of each assembly scheme are calculated.The results of eco-efficiency evaluation are obtained finally,contuibuting to analyze the results,put forward reasonable suggestions and improvement measures.