Abstract:
Production rates and costs of three forest road
construction machines (Ford County 1164 tractor,
D4D and D6D Caterpillar bulldozers) were analysed
and compared. Results showed that differences in
production rates were attributed mainly by the type
and the size of the machine, driver's working experience
and the nature of the terrain side slope.
Compared to other subgrade productivity
studies, machine production rates found in this study
were considered to be reasonably high. The mean
production rates for the D6D, D4D and the County
tractor were 129.0 m3/h, 41.0 mVh and 28.1 mVh
respectively. High productive time, easily workable
soils and few obstacles encountered during
earthworks operation were the major factors which
contributed to high machine production rates.
Cost analysis showed that the higher the machine
production rate the lower the subgrading cost
and vice versa. The mean production costs for the
D6D, D4D and the County were estimated to be US$
0.49/m3, US$0.79/m3 and US$0.76 /m3 respectively.
The estimated machine production costs were more
or less the same as those estimated elsewhere.
Although low machine production cost is usually
the criterion used in choosing the machine to be
used for road construction works, this paper recommends
that other factors be considered.
