A Comparative Study On Main Construction Cost Of Residential Projects In Prefabricated And Traditional Construction Modes

With the theme of green development continues to be followed,implementing prefabricated construction has become an important way for the construction industry to cope with the reduction of the demographic dividend and the transformation of the construction industry.Although the implementation of prefabricated construction in China has been early,the cost problem has always hindered its large-scale application.in order to have a better understanding of the construction cost performance under prefabricated and traditional construction model,paper selects the perspective of government and analyzes the cost structure of residential construction cost under two construction modes.According to the construction process and construction method,the composition of labor cost,material fee,machinery fee and other expenses in construction cost are classified and analyzed.Then,collect the cost data and completion settlement documents of 8 cast-in-place houses and 27prefabricated houses in the Beijing area and 3 sets of prefabricated houses in Shenyang,and use interviews to collect basic information and classify dispute fees.In the labor cost comparison,the allowable range of cost changes is defined;in the material cost comparison,the cost error caused by the time value is eliminated by comparing the consumption of the main materials.The study found that the construction cost per unit area constitutes a stable proportion of the cost of each part of the cast-in-place project,the proportion of material costs per unit area is the highest,the labor cost is second,and the project cost is the third,the mechanical fee,management fee and fee per unit area.The proportion of tax is small;the labor cost per unit area of the prefabricated area is slightly increased,and the proportion of material expenses is greatly increased.As the assembly rate increases,the overall increase is obvious;the tax value per unit area is significantly improved.The construction cost per unit area of project B and C is generally 10%-50%,and the construction cost per unit area of project D is generally 50%-100%higher,and the cost increase is obvious.Calculated by means of average value,the number of labor costs per unit area of the assembly-type housing area of the prefabricated house area is 10%,20%of the total number of items is 70%,50%.In terms of material cost per unit area,the material cost per unit area of prefabricated houses is generally above 900 yuan/m~2,and the maximum value is 1697.5 yuan~2,which is generally 30%higher than that of cast-in-place houses;in terms of main material consumption,the construction site of prefabricated residential units is significantly reduced,but the total consumption is higher than that of the cast-in-place residential project,and the figure reached 0.6m~3/m~2.In terms of steel consumption,steel consumption per unit area of cast-in-place projects is generally 15%-25%higher than that of prefabricated houses.On the whole,the mechanical cost per unit area of cast-in-place housing is higher than the mechanical cost per unit area of the assembled project,which is about 10%higher.The span of management area value of prefabricated houses is large,and the number of projects larger than 60 yuan/m~2 accounts for 88.5%,which is much higher than the average of management fees for cast-in-place houses.The unit area fee for prefabricated residential units is concentrated between 40-50 yuan/m~2,which is relatively uniform.The average unit cost per unit area of the cast-in-place project is 24.1 yuan/m~2.The tax on the unit area of prefabricated houses varies greatly.The value is distributed at 51.29 yuan/m~2-187.27 yuan/m~2,which is much higher than the cast-in-place residential tax range of 32-36 yuan/m~2.Last but not at least,the analysis found that the reasons for the difference in construction cost between fabricated and traditional construction houses are concentrated in four aspects:construction management maturity,material use grade,organization production mode and building structure.Finally,the construction cost reduction measures for prefabricated houses are proposed for the above reasons.Improve the cost management recommendations for prefabricated homes.