Estimation of cost and the amount of production in construction of forest road by combining hydraulic excavator and bulldozer (Case study: Liashisera district, Guilan Province)

Using machines such as hydraulic excavator and bulldozer is very common in construction of forest roads, and their costs have a major share from the hourly cost of a road construction project. Therefore, the estimation of production and costs of each apparatus production unit is regarded as a powerful mean for appropriate management and optimum usage of the facilities. In Liashisera district situated in 27th watershed of Amlash, a combination of two machines of hydraulic excavator and bulldozer were used in the road construction due to economic and environmental considerations. Majority of excavation operations were initially carried out by hydraulic excavator, and the bulldozer was used in the final stage to correct the slope and prepare the road bed for pouring sand scattering. The components of daily construction work including useful and useless times, technical and personal delays were assessed by time study technique in various slope categories. The results showed the average of production amounts of two machines in the slope classes of 10-30, 30-50 and 50-70 percent to be 71.23, 61.49 and 87.18 m3/h and 13.31, 20.87 and 12.28 m/h, respectively. Production cost of two machines per useful working hour was shown to be 8267 IRR per m3 and 39325 IRR per m