.,.
44 TRANSPORTATION
Output of vehicles for transportation of materials depends on :(a) Carrying capacity of vehicles by weight or volume, whichever is critical. (b) Distance to be travelled. . (c) Time taken in loading. and in unloading. (cl) Idle time in waiting for turn at loading ‘and unloading point, where, applicable. (e) Time lost in payment, documentation and checking .at loading and unloading points and at octroi and check posts, if any. Average speed. of vehicle depending on the condition of road, vehicle and traffic. (f) The carrying space in a ten tonne truck measures approximately 14’ - 7” x 7’ - 3” x 1’ - 10” (height of tailboard), which for all practical purposes of calculations is taken as 185 cft or 5.3 cu m. Average speed of trucks may be taken as 25 kmph. The speed will work out lesser for short trips and may go up to about 35 to 40 kmph for long distances to be travelled on open roads. Time required for loading and unloading of various building materials using manual labour is given in the table below. LOADING / UNLOADING TIME
Time to be allowed (per unit) in minutes :
Loading’ ‘.
‘Materials handled ,. _ :
10 tonne 3000 Nos ,14’cd m 5.3 cu m
Cement in bags Flooring tiles, of20 x 20 cm size Timber in cut sizes Miscellaneous stores
Time’ required per round.trip of =t + truck in minutes .. : : . W h e r e :..
120D ------s
Unloading’
Unit .i .’
Ideal strength ‘. Time in of labour gang to minutes _. : be employed
per tonne 1.000 Nos per.cu m per cii in
5
9
3 .‘6 6 6 3 6’ 6 6
8
Ideal Strength of labour gang to be employed
Time in minutes
2
3
.
30. 12 6. 4 ‘30 10 ‘. 10’
3 .6 6 4 B 6 6 6
’
Number of trips to be done by a truck L per day
t
= Time taken in minutes for loading + time taken in minutes for unloading + average time lost in minutes per trip for payment, documentation, checking, octroi, toll posts etc., as applicable. D = One way distance in km: H = ‘Number of hours of work per day. S =’ Speed of truck in km per hour.
Efficient loading using chutes or machine operated shovels. for loading, ‘and unloading by tipper trucks/dumpers for ‘materials like earth,. sand, shingle, aggregate, boulders, stones etc., requires about 4 minutes per vehicle for loading and 3 minutes per vehicle for unloading, inclusive of manouvring the vehicle in position; _:’ Regional transpoit authorities allow 6 labourers to travel along with the truck for loading and unloading purposes. Where a ,very large quantity of materials is to be moved employing several trucks, separate stationery gangs at the loading and . ‘unloading points can be employed, leading to economy: : :’ ‘. When checking back on the number of kilometres done suitable allowance should be made for the movement of vehicle .. from its place of parking to duty and back, (say 6 km/day on an average). :. .: .. a two-bullock cart may be taken as 1.25 cu m or 1 tonne travelling at a speed of about 3 to.4 .
