S.N. Cable Tunnels Cable Galleries- As the cable are underground and not open to
environment. There is lack of natural ventilation
and illumination. Hence, fault traceability is very
difficult during operation.
As the cable are open to environment.
here is adequate natural
ventilation and illumination. Hence,
fault traceability is very comfortable
during operation.- Entry of water inside cable tunnels is the biggest
problem. This creates nuisance in cable tunnel
maintenance during plant operation.
Cables are overhead on gallery
structures hence problem of
water entry is not there. It can be
maintained neat and clean if dust is
not there.- Tunnels are invisible to visitor eye sight. Hence,
plant looks aesthetically good, neat and clean
without network of cables.
Cables galleries are visible to visitor
eye sight hence plant looks
aesthetically not good due to spread
network of cables.- Flexibility of expansion is very difficult due to
underground construction work.
Flexibility of expansion is easier due
to open construction work.6.4 Commercial Comparison:
Apart from technical viability of any proposal commercial aspect is most important
for decision making. Costing of variable should be done for project implementation
phase with anticipation index parameters.
Here is the sample of cost sheet per unit of item wherein costing of cement, steel,
concrete and labor rates are taken from general market. The costing of both
gallery as well tunnels are estimated for similar capacity/ size of cable route.
We have collected input data from recent project for actual consumption of steel
cement, concrete and labour engaged. The systems are designed by Holtec and
universally have been implemented in various cement plant as per their suitability.
A brief comparison of costing on per unit basis for two systems is given for
reference purpose as under:
S. N. Items Unit Rate
Under Ground Over Head
Qty. Cost (Rs) Qty. Cost (Rs)
A) Contractor Cost
1 Excavation Cum 390 6.76 2,635 2.08 812
2 PCC Cum 3,750 0.18 661 0.05 190
3 RCC Cum 5,598 2.08 11,644 0.40 2,238
4 Shuttering SQM 870 7.28 6,334 1.10 960
5 Reinforcement MT 10,326 0.23 2,363 0.03 359
6 Structural Steel MT 34,783 0.03 870 0.30 10,593
7 Waterproofing