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CM 2113 Final Exams Prep Guide 2025- 2026 Set
- the work horses of the construction industry crawler (tracklaying) doz- ers
- an advantage of a wheel-type dozer as compared with higher speed a crawler dozer is
- they are designed to provide high drawbar pull and tractive effort
- the crawler dozer exerts adding to its versatility
- dozer tractors equipped with a blade are standard equipment for
crawler dozer
low ground-bearing pres- sure
excavating
- dozers equipped with special clearing blades are used land clearing for
- dozers equipped with push blades or blocks are used for
assisting scrapers to load
- a dozer can have a rear mounted ripper for loosing and breaking up rock
- 2 examples of dozer blades: tilted angled
- ideal production values (lcy/hr) are based on the fol- lowing conditions:
- ideal production values (lcy/hr) are based on the fol- lowing conditions:
100% eflciency Power-shift machines
Coeflcient of traction:
0.5 crawler machines 0.4 wheel machines
CM 2113 Final Exams Prep Guide 2025- 2026 Set
- ideal production can be based on hydraulic controlled blades
- when a machine pushes material within a narrow "slot" created by previous passes minimizing side spillage and maximizing the amount of material moved per pass
- more focused, efficient method for moving material by creating a contained path
slot dozing
slot dozing
- involves pushing material alongside another machine side-by-side dozing often used for larger volumes but with less efficiency due to potential material loss to the sides
- broader approach with potentially more material loss side-by-side dozing
- dozer: haul, than short less 300ft
- scraper: haul, to medium up 3,000 ft
- push loaded and single engine conventional scrapers
- conventional (push-loaded) single engine scrapers be- haul come uneconomical when: grades > 5% and grades > return 12%
- good for short hauls and in favorable material elevating scrapers
- dumping and spreading is one continuous operation spreading the load
- three main factors in scraper selection: job size, volume of mater- ial to move and maneuver room scraper configuration job conditions, grades, rolling resistance and ma- terial type
- must consider hourly cost for the entire push- er-scraper fleet.
- in this method a pusher tractor will push a loading scraper in the line and when complete, will go back and line up in another lane to push the next loading scraper
ALL
back-track loading
- in this method, a pusher tractor will push one loading chain loading scraper and then immediately enter the other lane and push a second loading scraper
- in this method, the pusher tractor will go one direc- tion to assist the first loading scraper and then return the opposite direction to assist in the second loading scraper
shuttle loading
- a major factor in selecting haul units distance
- types of trucks/hauling equipment: highway(on-road) ott-road
- methods of dumping:
rear bottom side conveyor
- frame: rigid or articulated
- engine: gasoline diesel propane
- drive configuration: 2 - wheel 4 - wheel 6 - wheel
- transmission: direct or diesel-electric
- capacity: gravimetric (tons) or volu- metric (cubic yards)
- trailer deposits a wind row of material. bottom dump
- two frames joined by pin and can operate over soft ground; retainer plate to increase load capacity
articulated truck
- trucks the job. mobilize
- is key to keep the fleet running so there are.
maintenance service trucks
- designed for a wide range of applications tires
- sight lines of things up close are limited ott-road truck drivers
- truck production:
- a shovel travel during the digging and loading cycle.
- developed by the hydraulic cylinders of the bucket, stick, and boom
- the boom and stick of a hoe are arranged for arc motion
does not
bucket penetration
downward
- a hoe is sometimes referred to by other names.... backhoe back shovel
- hydraulic hoes can be or mounted. wheel track
- a can be an added tool for carefully lifting heavy loads into position for an excavator
- lifting capability is given for over the and over the conditions
- means boom is extended over the idler end of the tracks
crane
front side
over the front
- job efficiency is based on: management conditions job conditions
- management conditions: Skill, training, and motiva- tion of workers Planning, job layout, su- pervision, and coordina- tion of work
- job conditions:
topography and work di- mensions surface and weather conditions
- typically cable operated allowing for longer reach draglines
- can be either cable or hydraulic operated but are typ- clamshells ically hydraulic
- the primary machines used for the vertical movement mobile cranes of construction materials tower cranes
- common mobile crane types: crawler lattice-boom truck mount- ed cranes for heavy lift rough terrain all-terrain telescoping boom truck mounted
- mobile cranes have a: mast boom boom stops counterweight
- these are truck cranes that have a self-contained tele- telescoping boom truck scoping boom mounted
- are put on large steel mats to reduce ground pressure outriggers and prevent damage to pavement
- structure is lightweight; this reduction in boom weight lattice-boom cranes means additional lift capacity, as the machine pre-
- the vertical movement of the load hoisting
- the horizontal movement of the trolley along the jib; this allows adjustment of the operating radius
trolleying
- when the jib rotates around the tower's vertical axis slewing
- either free standing or braced to the building struc- ture
- lifts itself on the building structure as the work pro- gresses
fixed base
climbing
- on rails or wheels traveling
- the height to which a tower crane can safely rise from maximum free- standing its base without the need of external bracing for later- height al stiffing
- the height to which a tower crane can safely rise from maximum braced height its base with additional external bracing for lateral stiffing
- the clear distance between the maximum height po- sition of the hook and the uppermost work area
available head room
- the motions a mobile crane uses to move a load are: hoist swing boom up/boom down travel
- a key aspect of crane capacity is quadrant of operation
- track-mounted crane
has three quadrants that are established by a radius running from the center of rotation through both the idler and final drive on each side of the crane or by lines parallel to the tracks
- depends on the quadrant position of the boom with respect to the machine's undercarriage
- in the case of crawler cranes, the quadrants that should be considered are:
- has three quadrants that are established by a radius running from the superstructure center of rotation through the outrigger support on each side of the crane
load capacity
Over the side Over the drive end of tracks Over the idler end of tracks
wheel-mounted crane
- cranes may fail by: stability or structural ca- pacity
- booms can be or angular tubular
- for a crawler crane rated load is of tipping load 75 %
- for a carrier-mounted crane on outriggers rated load is of tipping load
- for a carrier-mounted crane on rubber rated load is of tipping load
- structural capacity
·a crane operator must obey Emergency STOP signals from
- always give signals according to the right or operator's left
- as the designated signal person, your only duty is: signaling the crane by fo- cusing on the tasks
- use a to transfer hand signals when you can't see the operator, or a radio
middleman
- make sure the load does not pass workers above
- keep the crane at least feet away from power lines, keep an eye out overhead for power lines
- index finger points up, hand & forearm make a small circular motion
raise the load/cable up
- one hand is held flat, palm down, over the other hand raise the load slowly/cable which has a pointed index finger making a circular motion under the palm area
- outstretched arm, thumb pointing up, hand opening & closing
- outstretched arm, with index finger (or four fingers) pointing in the desired direction, try to keep thumbs in
- one hand is held flat, palm up, with the other hand having a downward pointed index finger making a circular motion over the palm area
up slowly
raise the boom/hold the load
swing the boom
lower the load slowly/ca- ble down slowly
- outstretched arm, fingers clenched with thumb point- lower the boom ing down
- both arms outstretched, fingers clenched with both thumbs pointing outward
- both arms outstretched, fingers clenched with both thumbs pointing inward
trolley out/extend the boom (telescoping)
retract the boom(tele- scoping)
- forearm circling forward, away from the body walk the crane forward
- forearm circling towards the body walk the crane backwards
- arm extended, palm down, starting folded in front of your chest extending outward
routine stop
- arms crossed waving emergency stop
- of radio silence means STOP. 3 seconds
- the signal person must be and know competent all the right moves
- the signal person must wear a high visibility vest
- ·a hand signal chart should be on the crane unit so everyone knows the signal system
mounted
