Forest road planting and control by mathematical programming and time study analysis
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Date
1985
Authors
Journal Title
Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
Planning and construction of forest roads have until very recently
been geared towards establishment and tending of plantation forests.
Now that most of the plantations are nearing maturity, it is essential
to plan and construct proper roads for harvesting purposes.
Hi is study was designed to develop a comprehensive methodology that
can be used by forest managers in the planning and control of forest
roads.
Specifically, the objectives of the study were:
- To evaluate the application of mathematical programming
methods to the design of safe and minimum-cost forest roads
- To test the feasibility of improving and controlling forest
road construction by mathematical programming
- To develop a comprehensive methodology for measuring and
estimating production rates and costs associated with forest
road construction.
To be able to plan, execute and control work operations for this
study, a representative 1.3 km access road was planned and constructed
at the Training Forest of the Sokoine University of Agriculture
between February 1981 and May 1984.
A number of mathematical models
and time study methods were tested and incorporated in this study in
order to develop a comprehensive methodology aimed at improving plan
ning, control and cost estimation procedures.
Based on the results
of this study, the following observatxons and conclusions are made;Planning and construction of forest roads have until very recently
been geared towards establishment and tending of plantation forests.
Now that most of the plantations are nearing maturity, it is essential
to plan and construct proper roads for harvesting purposes.
Hi is study was designed to develop a comprehensive methodology that
can be used by forest managers in the planning and control of forest
roads.
Specifically, the objectives of the study were:
- To evaluate the application of mathematical programming
methods to the design of safe and minimum-cost forest roads
- To test the feasibility of improving and controlling forest
road construction by mathematical programming
- To develop a comprehensive methodology for measuring and
estimating production rates and costs associated with forest
road construction.
To be able to plan, execute and control work operations for this
study, a representative 1.3 km access road was planned and constructed
at the Training Forest of the Sokoine University of Agriculture
between February 1981 and May 1984.
A number of mathematical models
and time study methods were tested and incorporated in this study in
order to develop a comprehensive methodology aimed at improving plan
ning, control and cost estimation procedures.
Based on the results
of this study, the following observatxons and conclusions are made;Planning and construction of forest roads have until very recently
been geared towards establishment and tending of plantation forests.
Now that most of the plantations are nearing maturity, it is essential
to plan and construct proper roads for harvesting purposes.
Hi is study was designed to develop a comprehensive methodology that
can be used by forest managers in the planning and control of forest
roads.
Specifically, the objectives of the study were:
- To evaluate the application of mathematical programming
methods to the design of safe and minimum-cost forest roads
- To test the feasibility of improving and controlling forest
road construction by mathematical programming
- To develop a comprehensive methodology for measuring and
estimating production rates and costs associated with forest
road construction.
To be able to plan, execute and control work operations for this
study, a representative 1.3 km access road was planned and constructed
at the Training Forest of the Sokoine University of Agriculture
between February 1981 and May 1984.
A number of mathematical models
and time study methods were tested and incorporated in this study in
order to develop a comprehensive methodology aimed at improving plan
ning, control and cost estimation procedures.
Based on the results
of this study, the following observatxons and conclusions are made;(a) With some modifications (in order to fit them to local
conditions), the standard engineering procedures used for
road design, layout and culvert size determination proved to
be fully satisfactory for use in Tanzania.
(b) Detailed time and work analyses conducted during the study
resulted in the establishment of production rates and costs
of forest road construction in Tanzania.
(c) Microcomputer-based linear programming and a transportation
tableau method were shown to be equivalent in determining
optimal allocation of earthwork during forest road planning.
Because it can be done by hand without recourse to a micro
computer, however the transportation tableau method is the
one likely to be favoured and adopted by most forest projects
in Tanzania.
(d) Before the actual road construction starts, the distance
between net cut and net fill areas can be used as a surrogate
for earthwork cost to determine the optimal road design.
The
study found that the design alternative selected on the basis
of minimum earth moving distance was also the one that mini
mized earthwork cost.
(e) A distance of 30 m between instrument stations along the
road appears to provide better accuracy for road layout and
design than using either intervals of 60 m or utilizing
"terrain breaks" to define instrument stations.
In this
study, both of these latter interval lengths provided data (a) With some modifications (in order to fit them to local
conditions), the standard engineering procedures used for
road design, layout and culvert size determination proved to
be fully satisfactory for use in Tanzania.
(b) Detailed time and work analyses conducted during the study
resulted in the establishment of production rates and costs
of forest road construction in Tanzania.
(c) Microcomputer-based linear programming and a transportation
tableau method were shown to be equivalent in determining
optimal allocation of earthwork during forest road planning.
Because it can be done by hand without recourse to a micro
computer, however the transportation tableau method is the
one likely to be favoured and adopted by most forest projects
in Tanzania.
(d) Before the actual road construction starts, the distance
between net cut and net fill areas can be used as a surrogate
for earthwork cost to determine the optimal road design.
The
study found that the design alternative selected on the basis
of minimum earth moving distance was also the one that mini
mized earthwork cost.
(e) A distance of 30 m between instrument stations along the
road appears to provide better accuracy for road layout and
design than using either intervals of 60 m or utilizing
"terrain breaks" to define instrument stations.
In this
study, both of these latter interval lengths provided data which tended to u. i erestimate actual road construction cost
by about 30 Z.
(f) The influence of road grade and alignment on log-truck haul
ing speed can satisfactorily be determined through the prin
ciples of engineering mechanics.
For instance, when deter
mining the hauling speed over a given road with a good number of
sharp curves, time to decelerate into and accelerate out of
the curve, the designed curve speed and the maximum safe
speed have to be considered.
(g) Of three road grade alternatives analysed in this study (6 Z,
8 Z and 10 Z), the 8 Z maximum grade recommended by the Forest
Division was found to be the grade that minimized the total
of earthwork and hauling costs.
(h) The use of the critical path method during culvert installa
tion resulted in the reduction of total installation time by
about 28 Z.
(i) Road construction is an expensive undertaking, but costs can
be reduced to about 1/3 to 1/2 of those estimated by road
contractors if proper
applied.
planning and control procedures are
The construction cost of this research road was
found to be shs 220 587/km, with earthwork and gravelling
operations taking 33 Z and 30 Z of the total construction
costs respectively, while road alignment/clearing and culvert
installation took 24 Z and 13 Z respectively.In addition to these conclusions, the methodological procedures
described in detail in this thesis provide a foundation on which
forest managers can base decisions related to the planning and cons
truction of forest roads.
Description
Keywords
forest, Road planting, Mathematical, Programming, Methodology, Time analysis