3.2.3 Trolley
The trolley should be as light as possible.
It is usually fabricated from mild steel
(MS) cylindrical or square hollow sections.
The size and shape of the trolley should
be designed as per the nature of the load
to be carried on it. Refer to the phtoto 4
for a typical trolley that was first used in
ropeways constructed by Practical Action.
3.2.4 Brakes
Brake consists of a 50 mm wide metallic strip
which is pinned to the channel of a sheave
frame at one end and to the wooden handle
at the other end. The strip should cover at
least one quarter of the circumference of the
sheave. It usually has a wooden lining but at
times, rubber linings are also used in addition
to the wooden lining.
3.2.5 Radius of the support saddle
In order to avoid the sharp bending of the
track rope at the support towers, the radius of
the support saddle should be minimum value
of 100 to the rope diameter.
design
Photo 4: Example of a typical ropeway trolley
Photo 5: Ropeway operator waiting to apply brake
3.3 Foundation Design
3.3.1 Introduction
Design and analysis of foundations must
guarantee that all loads (live and dead) acting
from the ropeway superstructure on the
foundations are safely transferred to the ground.
For the foundation design, following geotechnical
parameters should be known and accurately
established from the survey data.
Parameters:
Angle of internal friction – φ
Specific weight of soil/rock – Y
Maximum ground bearing pressure - σ
The foundation design is checked for the
following four failure modes:
3.3.2 Sliding failure
The earth or soil around the footing must be able
to mobilise enough passive resistance to prevent
the footing being slid off by the ropes. The factor
of safety adopted should be greater than 1.5.
Fsl = Retaining Forces > 1.5
Driving Forces
=
TCOS (β)
> 1.5
(W-TSIN (β)) TAN (φ)
where,
T= Rope tension
β= Rope inclination
φ= Angle of internal friction
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