Abstract
All construction work is executed by manpower and machine power. Manpower is measured by man-hours (mh), embracing various productivity rates. Machine power is measured by hoursepower-hours (hp-hr) of an engine or a motor mounted on a machine. One hp is assumed to be approximately equal to the power of eight men. If the operating efficiency of an engine or a motor is assumed to be 50% or 25%, one hp will correspond to the power of four or two men. Horsepower-hour can be converted to mh; thus the unit rate of hp-hr and the mh per unit work volume is established. The unit costs of a hp-hr and a mh will be estimated by the all-in cost. The combined productivity and total cost of men and machines are defined by equations comprising the productivity of each nationality and each group of machines, the working hour ratio and the hourly unit cost ratio of men and machines.
