Analysis Of The Relationship Between The Assembly Rate And The Cost Of Construction Projects

In recent years,China’s construction industry has made remarkable achievements.Among them,prefabricated building has gradually developed into one of the focuses in the field of construction,but there are still some problems and deficiencies.For example,the application and research development of prefabricated building is not balanced.Most of the research objects are residential projects,less public building projects,and most of the comparison of assembly rate and cost It focuses on prefabricated residential buildings and traditional cast-in-place concrete residential buildings,while the comparative analysis of different types of prefabricated buildings is slightly ignored.In this paper,we try to analyze the relationship between prefabricated building cost and prefabricated building cost.The construction area of these projects is large,and they all meet the A-level evaluation standard of prefabricated buildings,and the assembly rate is between 50.93% and 66.8%.The total construction area of all the research objects is more than 1.1 million square meters,and the total investment is more than 16 billion yuan.Firstly,based on the data of 123 prefabricated public buildings,the entropy method is used to calculate the influence weight between the number of five kinds of prefabricated components and the assembly rate.The results show that the influence weight of the number of pipeline separation components on the assembly rate is as high as 0.55,followed by the influence weight of the number of prefabricated vertical components on the assembly rate is as high as 0.33,which is far greater than the number of other prefabricated components.In addition,through the correlation coefficient method,the correlation analysis matrix between the assembly rate and the number of prefabricated components,the evaluation score of prefabricated components,the application proportion of prefabricated components,the prefabricated building area,the single party cost,the single building cost and other variables is constructed.The results show that the assembly rate has a positive impact on the single party cost and the single building cost.In order to control the cost of prefabricated buildings,the number of prefabricated vertical members,the number of prefabricated internal walls and the number of prefabricated pipeline separation should be controlled.Then,based on the data of 123 prefabricated public buildings,this paper uses lasso regression method to analyze and explore the multiple linear relationship between the assembly rate and the unit cost of prefabricated buildings,and uses genetic algorithm to explore the minimum unit cost and the optimal assembly rate,as well as the minimum unit cost range and the optimal assembly rate range based on the indicators recommended by the Ministry of housing and urban rural development.The results show that the minimum unit cost is 3269.09 yuan / m2,and the corresponding optimal assembly rate is 53.89%.When other variables remain unchanged,the unit cost of the building will change by 5.24% with every 1% change of the assembly rate;based on the index recommended by the Ministry of housing and urban rural development,the minimum unit cost ranges from 3269.09 yuan / m2 to 3440.32 yuan / m2,and the corresponding optimal assembly rate ranges from 53.89% to64.19%.Finally,123 prefabricated public buildings are divided into residential buildings and non residential buildings.The data of the two types of buildings are analyzed by difference analysis,Lasso regression analysis and genetic algorithm optimization analysis.Based on the indicators recommended by the Ministry of housing and urban rural development,the range of the lowest single square cost and the optimal assembly rate are explored.The results show that: 1.The impact of assembly rate on the cost of non residential buildings can be more reflected.2.Residential buildings: the lowest unit cost is 3268.99 yuan / m2,corresponding to the optimal assembly rate of 56.52%.When other variables remain unchanged,the unit cost of buildings will change by 3.5% with every 1% change of assembly rate;the lowest unit cost range is 3268.99 yuan / m2 ～ 3401.45 yuan / M2,corresponding to the optimal assembly rate range of 56.52% ～ 68.59%.3.Non residential buildings: the lowest single square cost is3270.85 yuan / m2,and the corresponding optimal assembly rate is 54.42%.When other variables remain unchanged,the single square cost of buildings will change by 5.30% with every 1% change of assembly rate;the lowest single square cost ranges from 3270.85 yuan /m2 to 3667.06 yuan / m2,and the corresponding optimal assembly rate ranges from 54.42%to 67.89%.The Enlightenment of this study is that the assembly rate and cost of prefabricated construction projects are closely related to the number of prefabricated components.The assembly rate is mainly affected by the number of pipeline separation,followed by the number of prefabricated vertical components.In addition to the assembly area,the cost of single building is most affected by the number of prefabricated enclosure walls,the number of prefabricated internal walls and the number of prefabricated pipeline separation.In addition,the assembly rate of prefabricated construction projects is positively correlated with the cost of prefabricated construction projects,but in terms of the degree of correlation,the impact of residential buildings is lower than that of non residential buildings.Therefore,it can be concluded that when controlling the building assembly rate,priority should be given to the number of pipeline separation and the collocation and design of vertical prefabricated components.In addition,in the design of prefabricated public building projects,in order to obtain the maximum economic benefits,the assembly rate can be appropriately controlled between 53% and 64%.