Question1 A 120 cy per hr maximum output pump is used to place the concrete for
ID: 1713034 • Letter: Q
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Question1 A 120 cy per hr maximum output pump is used to place the concrete for a 200 cy slab. The concrete is supplied by 8 cy transit-mix trucks arriving to the site on 12 min intervals. The concrete batch plant is located 5 miles from the site. Average truck speed is 30 mph. Each transit-mix truck takes, on average, 10 min to discharge. The placement crew size is 7 workers. Average worker output is 5 cy of concrete per hr. (a) How long will the operation take? (b) How can the operation be reorganized more effectively? Question 2 High Lift Construction Co. has determined that the heaviest load to be lifted on a project they anticipate bidding weighs 14,000 lb. From the proposed tower crane location on the building site, the required reach for this lift will be 150 ft. The crane will be equipped with an L5 jib and a two-part hoist line (see the Table 17.3 load chart). This critical lift is of a piece of limestone facing and will require a 2,000-lb spreader bar attached to a 300-lb set of slings. If assembled in the proposed configuration, can the crane safely make the pick?Explanation / Answer
question no (1):(a)
Total amount of concrete needed = 200 cy.
Maximum capacity of each truck = 8 cy.
In the concrete batch plant , capacity of avereage worker = 5 cy of concerte per hour = (5/60) of concrete per minute.
Total no. of workers = 7 ; Total capacity of workers = (7*(5/60)) = (7/12) of concrete per minute.
Assume that first truck going is fully reached its capacity, and it is said that next each trucks are reaching in next 12th minute.
So each truck have time for 12 minute to fill the concrete.
Total amount of concrete can fill in truck with 12 minute = (12*(7/12)) = 7 cy of concrete.
So..the 1st truck have 8 cy of concrete in it, and the rest of trucks have 7 cy of concrete in it.
Thus total trucks required to achieve the required amount = (200/7) = 28.57 nos.
So..1st truck 8 cy of concrete + 27 trucks of 7 cy of concrete+ 1 truck of 3 cy of concrete = 200 cy of concrete.
Thus total time required to achieve the required amount = 10 min + 324 min + 7 min = 5.6833 hr.
(b).
If the trucks can fullfill its capacity by considering all trucks are transporting 8 cy of cement each, by adding 1 more worker in the concrete batch. Then with less time we can complete this operation.
Consider all trucks are transporting 8 cy of concrete.
Total no. of trucks needed = 25 trucks.
Total time required = 10 min (1st truck) + 288 min (24 trucks) = 4.967 hr.
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question no (2)
Insufficiant data.
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question no (3)
Chemical dust suppressants are a dust management tool that forms a thin flexible coating in wet environments. It controlls the dust due to wind,vehicle and traffic light equipments. It helps in rail cars to reduce of eliminate the dust particle emission by transportation and storage. it also used in mine haul roads which provides the acceleration of water penetration in the nearby areas.
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question no (4)
It is given that the whole period of project = 5 yrs.
Usage of tunnel each year = 60 times. so for whole 5 yrs it will be used for 300 times.
It is stated that periodical maintenance cost for 120 uses will be 4% of purchase cost.
Total materail cost for total uses = purchase cost + periodical maintenance cost + annual interest + modified cost.
Purchase cost = $30/sf
periodical maintenance cost = (4% of 30) * (300/120) = $3/sf.
annual interest = (5% of 30)* 5 = $7.5/sf.
modified cost = $6/sf.
Total cost for 300 uses = 30+3+7.5+6 = $46.5/sf.
Average material cost for each use = (46.5/300) = $0.155/sf.
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