GRAVITY GOODS ROPEWAY
3.3.3 Toppling/over turning failure
The anchor block should be checked against
toppling. The resisting moment must be at least
1.5 times the overturning moment.
Ft = Retaining moment > 1.5
Over turning moment
= TCOS (β)x h +TSIN(β)x b1 > 1.5
Wx 0.5b
where,
h = the depth of toe from the point of
application of tension in the vertical post
b = breadth of the anchor block
b1 = the horizontal distance from the point of
application of rope tension to the toe of
the block
3.3.4 Ground shear failure/bearing capacity
The pressure transmitted to the ground from the
imposed loads must be less than the bearing
capacity of the soil,
σ = W+Eav + M.b
b.l - I .2
where, moment of inertia = l.b3
12
Moment at bottom centre,
M= TCOS (β)Xh + Eah x h – Eav xb
3
Eah = 0.5 λ γ h2 Eav = Eah x Tan (δ),
δ = 2/3Ф
σ should be less than the safe bearing capacity
of soil.
Similarly, the safety of anchorage post should be
checked against the shear stress and the plumb
concrete.
3.3.5 Shear force in the vertical posts
The size of the anchorage post and the
reinforcement provided should be designed in a
way that the permissible shear force is more than
the shear force on the vertical posts due to the
rope tension.
Shear force due to rope tension (τ)
= TCOS(β)/(πd2/4 )
Permissible shear force = πD4τc + τrπd2
4
where, τr and τc are the permissible shear stress
of concrete and rods respectively.
3.3.6 Stress in plumb concrete
The tensile and compressive stress developed
in the plumb concrete of the anchorage blocks
should also be checked against its permissible
stress.
Stress on the plumb concrete,
σ = TCOS (β)Xh + M.h
d.h
- I .2
N.B Refer to the relevant soil engineering/
foundation design book for details on foundation
design.
3.4 The Design Team and Qualification
The design team should consist of two professionals
having following qualifications and experiences:
Civil engineer – A civil engineer having
minimum of five years of experience in survey
design of trail bridges and/or two years of
experience in ropeway designing. He/she
should have sound knowledge of rope and
should be aware of prevailing standards,
norms and codes of practices for ropeway.
Mechanical engineer – A mechanical
engineer having sound knowledge of ropeway
accessories with two years of experience in
designing of ropeway accessories/parts.
26