CM 2113 Final exam

The ________________ is very effective for side-casting material, particularly for backfilling or making sidehill cuts.

Angle Blade

Semi-U blade

Combination of the S and U blade designs

crawler dozer

(tracklaying) - the work horses of the construction industry

Cushion blades

Mounted on large dozers that are used primarily for push-loading scrapers. limited utility in pushing material and should not be used for production dozing. Cannot be tilted, pitched or angled.

Pros and cons of different types of cranes

Rough terrain crane "pickers" -Pros= off road applications, set up quickly, very maneuverability. -Cons= limitation of capacity and cost of freight *All terrain crane -pros= travel on highway and rough terrains -cons= limitation of capacity, set up time, maneuverability and foot print. *Crawler -Pros= don't require outriggers, very high lifting capacity, any site even soft soils, travel with load -Cons= expensive, set up time, large foot print, lot of matting, larger number of fall off loads

Straight blades

Shh hi pet and medium distance passes, such as backfilling, grading, and spreading full material

______________ is a technique whereby the blade end spillage from the first pass or the sidewalls from previous cuts are used to hold the material in front of the dozer blade on subsequent passes.

Slot dozing

Which of the following is a job condition that could affect the operator's job efficiency?

Surface and weather conditions

Tower cranes

The flexibility of its freely suspended hook moving in three planes provides a tremendous advantage in terms of load pick-up and positioning. Advantage of having both the operator and jib above the construction site.

Hoisting

The hoist cable runs from the hoist drum located on the crane's counter jib, through the jib and then to the trolley and down to the hook

Lattice-boom truck mounted cranes

The lattice-boom structure is lightweight. This reduction in boom weight means additional lift capacity, as the machine predominately handles hoist load and less weight of boom

rough-terrain cranes

These units are equipped with unusually large wheels and closely spaced axles to improve maneuverability at the job site. They earn the right to their name by their high ground clearance, as well as the ability to move on steep slopes

All-terrain cranes

They have an undercarriage capable of long-distance highway travel. Yet the carrier has all-axle drive and all-wheel steering, crab steering, large tires, and high ground clearance.

Fill factor is the ratio of the actual loose volume of material in the bucket compared to the bucket's rated-heaped capacity. It varies based on the type of material being handled and the type of excavator.

True

Universal blades

Working stockpiles and drifting loose or no cohesive materials

crawler cranes for heavy-lifting

additional counterweight mounted on a wheeled platform to increase lifting capacity. Ring system, "ringer," a heavy counterweight system supported on a large circular turntable ring

Fill factor

adjusts heaped capacity in lcy based on the type of material being handled

push-pull tandem powered scrapers

all wheel drive scrapers equipped with coupling devices that enable 2 scrapers to assist eachother in loading

single powered scraper

one engine

auger scraper

self loading scrapers that use a rotating auger to lift material into the bowl. Available in single and tandem configurations. More costly to own and operate.

single powered axle pusher-loader wheel-tractor scrapers

suited for jobs where the haul-road rolling resistance is low and grades are minimal. They become uneconomical when haul grades are greater than 5% and return grades are greater than 12%

loading

tandem powered scrapers sometimes require help

Trolleying

the horizontal movement of the trolley along the jib; this allows adjustment of the operating radius.

dozers

they are designed to provide high drawbar pull and tractive effort.

2-axle scraper

towed by a tractor, effective in short hauls

Slewing

when the job rotates around the tower's vertical axis

Buckets of loaders are rated in both heaped and struck capacities. _________________ is based on the SAE standard of a 2:1 material repose angle.

Heaped capacity

self-loading scrapers

Heavier and more costly than conventional scrapers, can be economical in isolated work and for stripping materials

Which of the following factors need to be considered when selecting a proper scraper for your project?

-Scraper configuration -Volume of material -Job size

Which of the following work tasks can be performed by a dozer?

-Spreading -Striping -Backfilling

telescoping boom truck mounted cranes

-Travel on highways, can change boom length, have outriggers for stability. -Outriggers on large steel mats to reduce ground pressure and prevent damage to pavement -Crane positioned on hollow-core precast concrete panel slab

crawler dozer

-good for short distance -can handle tight soil -can push large blade loads -exerts low ground bearing pressure -works on almost any terrain -can work on soft ground and mud slick surfaces

A contractor wants to investigate the production and cost differences of using a 4S blade on a crawler-type dozer (D4H-4S). The material is dry clay and is to be moved a distance of 150 ft from the beginning of the cut. The dozing is uphill on a 20% grade. The operator will have average skill. The site conditions will be dark for visibility. The material weighs 108 pcf in the bank state. Job efficiency is assumed to be equivalent to a 50-min hour. What is the grade correction factor? Please choose a range from the following where your reading will be within.

0.4-0.6

A contractor wants to investigate the production and cost differences of using a 4S blade on a crawler-type dozer (D4H-4S). The material is dry clay and is to be moved a distance of 150 ft from the beginning of the cut. The dozing is uphill on a 20% grade. The operator will have average skill. The site conditions will be dark for visibility. The material weighs 108 pcf in the bank state. Job efficiency is assumed to be equivalent to a 50-min hour. What is the operator correction factor?

0.75

What is the job efficiency for this machine based on the given scenario?

0.8

A contractor wants to investigate the production and cost differences of using a 4S blade on a crawler-type dozer (D4H-4S). The material is dry clay and is to be moved a distance of 150 ft from the beginning of the cut. The dozing is uphill on a 20% grade. The operator will have average skill. The site conditions will be dark for visibility. The material weighs 108 pcf in the bank state. Job efficiency is assumed to be equivalent to a 50-min hour. What is the visibility correction factor?

0.80

A contractor wants to investigate the production and cost differences of using a 4S blade on a crawler-type dozer (D4H-4S). The material is dry clay and is to be moved a distance of 150 ft from the beginning of the cut. The dozing is uphill on a 20% grade. The operator will have average skill. The site conditions will be dark for visibility. The material weighs 108 pcf in the bank state. Job efficiency is assumed to be equivalent to a 50-min hour. What is the work efficiency correction factor?

0.83

A contractor wants to investigate the production and cost differences of using a 4S blade on a crawler-type dozer (D4H-4S). The material is dry clay and is to be moved a distance of 150 ft from the beginning of the cut. The dozing is uphill on a 20% grade. The operator will have average skill. The site conditions will be dark for visibility. The material weighs 108 pcf in the bank state. Job efficiency is assumed to be equivalent to a 50-min hour. What is the material-weight correction factor? Assume the percent swell is 12%.

0.88

A contractor is planning to use single pusher scrapers to move 90,000 cubic yards of soil, and the expected production of a single pusher scraper assuming adequate pusher support is 230cy/hr. It has been decided there will be total 8 scrapers operating on the site with a back-track loading method. The estimated cycle time for each scraper is 7.5 min. Following the previous question, what is the expected production rate of this scraper fleet if only one pusher is available?

1,150

What factors affect dozer real production rates?

1. Blade type 2. Type and condition of material 3. Cycle time

cranes selection

1. Operating radius 2. Lifting capacity 3. Lifting speed

How to classify trucks

1. Size and engine type (gas, diesel) 2. Number of gears 3. Drive type (2 wheel, 4 wheel) 4. Number of wheels and axles 5. Method of dumping 6. Material being hauled 7. Holding capacity

scraper fixed cycle time

1. Spot time 2. Load time 3. Maneuver and dump time

Scrapers production cycle

1. loading 2. haul travel 3. dumping and spreading 4. turn 5. return travel 6. turn getting next load

A contractor has decided to use a dragline to excavate a ditch to drain stormwater runoff from her construction site. The material to be excavated is a light moist clay weighing 2,000 pounds per bank cubic yard with a swell of 18% and shrinkage of 25%. Given the density of the material to be loaded, the contractor has determined that the largest heavy-duty dragline bucket that can be safely mounted on the crane has a rated capacity of 2.5 cubic yards. We assume that we know the average depth of the dig is 11.9 feet and the average angle of the swing is 75 degrees, and the contractor plans to operate the machine about 48 minutes per hour. Please answer this question based on the following given tables.What is the swing-depth factor for this machine based on the given scenario?

1.00

Using Fig. 17.13, select the minimum-length boom required to hoist a load of 80,000 lb from a truck at ground level and place it on a platform 76 ft above the ground. The minimum allowable vertical distance from the bottom of the load to the boom point of the crane is 42 ft. The maximum horizontal distance from the center of rotation of the crane to the hoist line of the crane when lifting the load is 40 ft.

120

A contractor is planning to use single pusher scrapers to move 90,000 cubic yards of soil, and the expected production of a single pusher scraper assuming adequate pusher support is 230cy/hr. It has been decided there will be total 8 scrapers operating on the site with a back-track loading method. The estimated cycle time for each scraper is 7.5 min. How many pushers are required to serve the fleet of 8 scrapers?

2

A contractor has a project involving the construction of a small manufacturing plant. The contractor has selected a borrow site and has decided to use 27-cubic yard dump trucks to haul the needed fill material. The contractor has decided to use a hydraulic excavator with a shovel attachment to load the trucks. The excavator has expected productivity as 422cy/hr at 100% efficiency, and the truck cycle time excluding loading is 0.48hr. The job site operation efficiency is assumed as 0.8. Please answer the next two questions. What is the expected fleet production if only 6 trucks are available to the fleet?

238

What is the actual production rate for this machine based on the given scenario?

244

A contractor has decided to use a dragline to excavate a ditch to drain stormwater runoff from her construction site. The material to be excavated is a light moist clay weighing 2,000 pounds per bank cubic yard with a swell of 18% and shrinkage of 25%. Given the density of the material to be loaded, the contractor has determined that the largest heavy-duty dragline bucket that can be safely mounted on the crane has a rated capacity of 2.5 cubic yards. We assume that we know the average depth of the dig is 11.9 feet and the average angle of the swing is 75 degrees, and the contractor plans to operate the machine about 48 minutes per hour. Please answer this question based on the following given tables.

305

A contractor has a project involving the construction of a small manufacturing plant. The contractor has selected a borrow site and has decided to use 27-cubic yard dump trucks to haul the needed fill material. The contractor has decided to use a hydraulic excavator with a shovel attachment to load the trucks. The excavator has expected productivity as 422cy/hr at 100% efficiency, and the truck cycle time excluding loading is 0.48hr. The job site operation efficiency is assumed as 0.8. Please answer the next two questions. What is the expected fleet production if 11 trucks are available to the fleet?

422

tower cranes

5% working margin be maintained on every twoer crane lift

A 25-ton truck-mounted hydraulic crane is being used on a construction site. The maximum horizontal distance from the center of rotation of the crane to the hoist line of the crane when lifting a load of 9,000 lb will be 40 ft. Use Table 17.2 crane data to select the minimum length boom required to safely hoist the load.

64

A contractor has decided to use a dragline to excavate a ditch to drain stormwater runoff from her construction site. The material to be excavated is a light moist clay weighing 2,000 pounds per bank cubic yard with a swell of 18% and shrinkage of 25%. Given the density of the material to be loaded, the contractor has determined that the largest heavy-duty dragline bucket that can be safely mounted on the crane has a rated capacity of 2.5 cubic yards. We assume that we know the average depth of the dig is 11.9 feet and the average angle of the swing is 75 degrees, and the contractor plans to operate the machine about 48 minutes per hour. What is the optimum depth of cut for this machine based on the given scenario?

8.5

A contractor has a project involving the construction of a small manufacturing plant. The contractor has selected a borrow site and has decided to use 27-cubic yard dump trucks to haul the needed fill material. The contractor has decided to use a hydraulic excavator with a shovel attachment to load the trucks. The excavator has expected productivity as 422cy/hr at 100% efficiency, and the truck cycle time excluding loading is 0.48hr. The job site operation efficiency is assumed as 0.8. How many dump trucks will be needed to work with the excavator?

9

Side-to-side

Blade-to-blade dozing. Two machines maneuver so that their blades are next to each other during the pushing phase of the production cycle.

Scrapers

Excavating, loading, hauling and dumping material over medium to long haul distances

the capacity of a scraper

Expressed in bank cubic yards, approximated by multiplying the loose volume in the bowl by an appropriate swell factor

An advantage of a crawler dozer as compared with a wheel-type dozer is higher speed.

False

Which of the following is not a disadvantage of a crawler crane?

Limited capacity

Excavators job efficiency

Management conditions: - Skill, training, and motivation of workers - Planning, job layout, supervision, and coordination of work Job conditions: - Topography and work dimensions - Surface and weather conditions

cranes

Mobile cranes and tower cranes are the primary machine used for the vertical movement of construction materials

backtrack loading

Most common. It permits all scrapers to load in the same area. However, the slowest bc of the addition pusher travel distance

Articulated trucks consist of two individual frames joined by pin, and can be easily operated over soft ground.

True

Dozer is good for applications of less than 300ft short haul, and scraper is good for applications of up to 3,000ft medium haul.

True

Dozer

can have a rear mounted ripper for loosing and breaking up rock

top slewing cranes

cranes can increase their height

trucks

distance is a major factor in selecting haul units

tandem powered scraper

dual engines, greater tractive effort, 25% initially more expensive then conventional scrapers. For that reason, they commonly considered a specialized machine, open up a job, work on extremely adverse grades and on soft ground conditions

Dozers

equipped with a blade are standard equipment for excavating

Dozers

equipped with push blades or blocms are used for assisting scrapers to load

Dozers

equipped with special clearing blades are used for land clearing

crawler dozer

exerts low ground-bearing pressure adding to its versaility

push-loaded wheel scraper

has potential for high travel speeds on favorable roads

crawler cranes

mounted on a pair of parallel crawler tracks, which provide the crane with good travel capability around the job site

Liftem High Construction Co. has determined that the heaviest lift on a project they are estimating weighs 26,000 lb. The project's tower crane will make this lift (see Table 17.3). From the proposed tower crane location on the building site the required reach for this lift will be 90 ft. The crane will be equipped with an L6 jib and a four-part hoist line. This critical lift is of a piece of HVAC equipment and will require a 1,400-lb spreader bar attached to a 300-lb set of slings. If assembled in the proposed configuration, can the crane safely make the pick?

no

elevating scrapers

not designed to be push loaders, use a ladder to lift material into the bowl. However the ladder is dead weight during the haul cycle. Used for utility work, good in small quantity situations. No pusher is required. They cannot handle rocky materia