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CSCS Tower Crane study materials
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CSCS Tower Crane practice questions

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Question 1Tower Crane Types, Components, and Configuration

In tower crane terminology, what does the term 'jib' refer to?

  1. The horizontal working arm that carries the trolley and load Correct answer.
  2. The concrete foundation that anchors the crane
  3. The counterweight block at the rear of the crane
  4. The vertical mast section that supports the slewing unit

Explanation

The jib is the horizontal boom along which the trolley travels to position loads at varying radii. It is distinct from the vertical mast and the counterweight assembly.

Question 2Tower Crane Types, Components, and Configuration

Which tower crane configuration has its jib and counter-jib rigidly connected to the mast and relies on a slewing ring to rotate the whole upper assembly?

  1. Self-erecting crane
  2. Trolley-jib bottom-slewing crane
  3. Top-slewing crane Correct answer.
  4. Luffing jib crane

Explanation

In a top-slewing crane the slewing mechanism sits at the top of the mast and rotates the entire jib-and-counter-jib assembly as a unit. Bottom-slewing designs rotate from the base instead.

Question 3Tower Crane Types, Components, and Configuration

What is the primary function of the counterweight on a tower crane?

  1. To resist the overturning moment created by the load on the jib Correct answer.
  2. To anchor the mast to the foundation bolts
  3. To dampen oscillation of the hoist rope during travel
  4. To increase the crane's maximum lifting capacity at the jib tip

Explanation

The counterweight produces a rearward moment that offsets the forward overturning moment from the load and jib. This keeps the crane stable about its base.

Question 4Tower Crane Types, Components, and Configuration

A trolley-jib tower crane positions a load at different radii by:

  1. Rotating the counter-jib toward the load
  2. Changing the angle of the jib relative to horizontal
  3. Extending hydraulic mast sections
  4. Moving the trolley along the jib Correct answer.

Explanation

On a trolley-jib (hammerhead) crane, the trolley runs along the horizontal jib to change the load radius. The jib angle stays fixed.

Question 5Tower Crane Types, Components, and Configuration

Which component connects the jib and counter-jib to the top of the mast and transmits loads into the slewing ring?

  1. The hook block
  2. The turntable or slewing platform Correct answer.
  3. The cathead
  4. The trolley

Explanation

The turntable (slewing platform) is the structural interface between the upper works and the mast, transferring loads through the slewing ring. The cathead is the pendant-support tower above it.

Question 6Tower Crane Types, Components, and Configuration

What is the purpose of the pendant bars (ties) on a hammerhead tower crane?

  1. To provide a walkway for maintenance access
  2. To support the jib and counter-jib in tension from the cathead Correct answer.
  3. To carry the hoist rope from the drum to the trolley
  4. To guide the trolley along the jib rails

Explanation

Pendant bars are tension members running from the cathead to points along the jib and counter-jib, supporting them. They carry tension rather than the hoist load directly.

Question 7Tower Crane Types, Components, and Configuration

A luffing-jib tower crane changes working radius primarily by:

  1. Raising or lowering the jib angle Correct answer.
  2. Slewing the upper works faster
  3. Adding counterweight blocks
  4. Moving a trolley along a horizontal jib

Explanation

Luffing cranes pivot the jib up or down to change radius, similar to a lattice-boom mobile crane. There is no trolley travel along the jib.

Question 8Tower Crane Types, Components, and Configuration

Which of the following best describes a self-erecting tower crane?

  1. A crane mounted permanently on a rail track
  2. A crane that folds and unfolds its own mast and jib for transport and erection Correct answer.
  3. A crane assembled by a separate mobile crane at each site
  4. A crane that climbs the building as floors are added

Explanation

Self-erecting cranes are designed to fold for road transport and unfold themselves on site without an assist crane. This distinguishes them from cranes requiring an erection crew and mobile crane.

Question 9Tower Crane Types, Components, and Configuration

On a tower crane, the hoist drum and hoist motor are typically located:

  1. On the counter-jib side of the slewing unit Correct answer.
  2. Inside the mast base section
  3. On the trolley at the jib
  4. At the hook block

Explanation

The hoist machinery is mounted on the counter-jib side of the upper works to act as counterbalance and keep the rope runs short. The trolley carries only sheaves, not the drum.

Question 10Tower Crane Types, Components, and Configuration

A crane's load chart shows a capacity of 2.4 t at 40 m radius and 4.0 t at 25 m radius. Which principle explains the decrease in capacity as radius increases?

  1. The counterweight becomes less effective at greater radius
  2. The trolley motor loses power at the jib tip
  3. The hoist rope strength decreases with rope paid out
  4. The overturning moment and jib bending moment increase with radius Correct answer.

Explanation

Load moment equals load times radius, so a larger radius produces a larger overturning and bending moment for the same load. The chart therefore reduces allowable load as radius grows.

Question 11Tower Crane Types, Components, and Configuration

What is the function of the slewing ring bearing on a top-slewing tower crane?

  1. To raise and lower the jib for luffing
  2. To tension the pendant bars
  3. To allow the upper works to rotate relative to the mast while carrying vertical and moment loads Correct answer.
  4. To guide the hoist rope onto the drum

Explanation

The slewing ring is a large bearing that permits rotation between the mast and upper works while transmitting axial, radial, and moment loads. It is driven by the slewing motor and pinion.

Question 12Tower Crane Types, Components, and Configuration

A climbing tower crane differs from a fixed tower crane in that it:

  1. Has no counterweight
  2. Adds mast sections within a climbing frame as the building rises Correct answer.
  3. Rotates from the base rather than at the top
  4. Uses a luffing jib instead of a trolley jib

Explanation

Climbing cranes jack themselves upward and insert new mast sections inside a climbing frame tied to the structure. This allows the crane to rise with the building.

Question 13Tower Crane Types, Components, and Configuration

Which component is designed to limit the load moment so the crane cannot be overloaded beyond its chart?

  1. The load moment indicator (LMI) Correct answer.
  2. The trolley limit switch
  3. The anemometer
  4. The slewing brake

Explanation

The load moment indicator senses load and radius and compares the product to the chart, warning and then cutting functions before overload. It protects against both structural and stability overload.

Question 14Tower Crane Types, Components, and Configuration

A tower crane operator must lift a load that is within the chart at the required radius, but the jib will pass over an adjacent building. What configuration consideration is most relevant?

  1. Checking that the slewing arc is clear and setting slew limits if fitted Correct answer.
  2. Reducing hoist line parts to speed the lift
  3. Increasing counterweight to raise capacity
  4. Selecting a longer jib to increase reach

Explanation

When the slewing path is obstructed, the crane must be configured or limited so the jib cannot contact the obstruction. Slew limits or a clear slewing arc address this.

Question 15Tower Crane Types, Components, and Configuration

What is the purpose of the trolley limit switch on a trolley-jib crane?

  1. To limit the number of hoist line parts
  2. To stop trolley travel before it reaches the jib tip or the minimum radius Correct answer.
  3. To limit slewing speed in high wind
  4. To prevent the hook block from contacting the jib

Explanation

Trolley limit switches stop trolley travel at the extreme inboard and outboard positions. They protect the jib structure and prevent the trolley running off its track.

Question 16Tower Crane Types, Components, and Configuration

Which statement correctly distinguishes a hammerhead crane from a luffing crane?

  1. The hammerhead has no counterweight; the luffing crane does
  2. The hammerhead slews from the base; the luffing crane slews from the top
  3. The hammerhead cannot travel; the luffing crane always travels on rails
  4. The hammerhead has a horizontal jib with a trolley; the luffing crane pivots its jib Correct answer.

Explanation

The defining difference is the jib arrangement: a horizontal trolley jib versus a pivoting luffing jib. Both are typically top-slewing and both use counterweights.

Question 17Tower Crane Types, Components, and Configuration

What does the term 'reeving' refer to on a tower crane?

  1. The setting of pendant bar tension
  2. The calibration of the load moment indicator
  3. The pattern in which the hoist rope is threaded through sheaves to form the lifting lines Correct answer.
  4. The alignment of mast sections during erection

Explanation

Reeving is the rope path through sheaves and the hook block, which determines the number of parts of line. More parts of line increase capacity but reduce line speed.

Question 18Tower Crane Types, Components, and Configuration

A crane is rated for a maximum of 4 parts of line. An operator wants to lift a heavy load near the chart limit at a short radius. What reeving consideration applies?

  1. Use a single part of line to reduce rope wear
  2. Reeving has no effect on capacity, only speed
  3. Increase parts of line beyond the rated maximum to gain capacity
  4. Use the maximum permitted parts of line to match the required line pull Correct answer.

Explanation

The number of parts of line divides the load among rope lines, so the rated maximum reeving should be used when the load approaches the line-pull limit. Exceeding the rated maximum is not permitted.

Question 19Tower Crane Types, Components, and Configuration

Which device is intended to prevent the hook block from being pulled up into the jib or trolley?

  1. The hoist limit switch (over-hoist device) Correct answer.
  2. The slew brake
  3. The load moment indicator
  4. The trolley limit switch

Explanation

The hoist limit switch stops hoisting before the hook block contacts the jib or trolley. Two-block damage and rope failure are prevented by this device.

Question 20Tower Crane Types, Components, and Configuration

On a tower crane, the term 'working radius' is measured as:

  1. The horizontal distance from the slewing centre to the centre of the hook load Correct answer.
  2. The length of the jib from the cathead to the tip
  3. The vertical distance from the foundation to the hook
  4. The distance from the counterweight to the mast

Explanation

Working radius is the horizontal distance from the crane's slewing axis to the load's centre of gravity. It is the value used with the load chart to determine capacity.

Question 21Tower Crane Types, Components, and Configuration

A crane has a 60 m jib and lifts a load of 1.8 t at 55 m radius. The chart permits 2.0 t at 55 m. The load is then slewed so the radius stays constant but wind increases. What is the primary concern?

  1. Wind increases the effective load and overturning moment, so the lift may become unsafe Correct answer.
  2. The counterweight becomes heavier in wind
  3. The load moment is unchanged, so capacity is unaffected by wind
  4. Slewing reduces the radius and increases capacity

Explanation

Wind acting on the load and jib increases the effective load and the overturning moment, which can push the crane beyond its rated stability. The chart capacity does not account for added wind load, so the lift may become unsafe.

Question 22Tower Crane Types, Components, and Configuration

Which combination of crane features would be most appropriate for a project where the crane must operate in a confined site with no room for a horizontal jib to over-sail neighbouring property?

  1. A trolley-jib hammerhead crane with a long jib
  2. A bottom-slewing crane with a fixed horizontal jib
  3. A rail-mounted crane with an extended counter-jib
  4. A luffing-jib crane that can raise its jib to reduce over-sail Correct answer.

Explanation

A luffing jib can be raised to a steep angle, reducing the horizontal over-sail beyond the site boundary. This makes it suited to confined sites with adjacent property.

Question 23Tower Crane Types, Components, and Configuration

An engineer is reviewing why a tower crane's published capacity at maximum radius is much lower than at minimum radius. Which pair of factors best explains this?

  1. Hoist motor torque and brake wear
  2. Counterweight mass and foundation bolt size
  3. Overturning moment about the base and bending moment in the jib Correct answer.
  4. Trolley wheel friction and rope stretch

Explanation

Capacity falls with radius because both the overturning moment about the base and the bending moment in the jib increase with radius for a given load. These structural and stability limits set the chart values.

Question 24Tower Crane Types, Components, and Configuration

A crane is being configured with its jib pointing toward a power line that cannot be de-energized. Which configuration control is most directly relevant?

  1. Fitting and setting a slew limit to keep the jib away from the line Correct answer.
  2. Increasing the number of parts of line
  3. Reducing the counterweight
  4. Extending the jib length

Explanation

A slew limit restricts the crane's rotation so the jib and load cannot enter the prohibited zone near the power line. This is a configuration control applied before work begins.

Question 25Tower Crane Types, Components, and Configuration

A planner compares a top-slewing hammerhead crane and a bottom-slewing crane for a site surrounded by tall buildings. Which statement about their typical behaviour is most accurate?

  1. The top-slewing crane rotates only its base, leaving the jib fixed
  2. The bottom-slewing crane rotates its whole tower, requiring a clear circular base area Correct answer.
  3. The top-slewing crane cannot be tied to a building
  4. The bottom-slewing crane has no counter-jib

Explanation

A bottom-slewing crane turns the entire tower about its base, so the base and its surroundings must allow full rotation. A top-slewing crane rotates only the upper works above the mast.

Question 26Tower Crane Types, Components, and Configuration

On a typical tower crane, what is the primary structural role of the mast (tower section)?

  1. It provides the counterweight moment to balance the jib
  2. It supports the trolley and hoist rope along the jib
  3. It carries the vertical loads and overturning moments down to the foundation Correct answer.
  4. It houses the slewing motor and gearbox

Explanation

The mast is the vertical lattice or tubular column that transfers the crane's vertical loads and the overturning moment from the jib and counter-jib into the base or foundation. The counterweight moment is produced by the counter-jib and counterweights, not the mast itself.

Question 27Tower Crane Types, Components, and Configuration

Which foundation arrangement is commonly used where a tower crane must be tied to a completed building core for lateral stability?

  1. A ballasted cruciform base with no ties
  2. A floating pontoon base
  3. A wall-tied or anchor-frame arrangement with ties at specified levels Correct answer.
  4. A rail-mounted travelling base

Explanation

When a crane cannot achieve stability from its base alone, it is tied back to a structure such as a building core or slab at specified levels using wall ties or an anchor frame. These ties resist lateral forces and must be installed at the spacing and loads given by the manufacturer.

Question 28Tower Crane Types, Components, and Configuration

A planner must choose between a trolley-jib and a luffing-jib crane for a site where the crane will operate with its jib over a neighbouring occupied building and must keep the jib clear of an adjacent tower crane. Which feature of the luffing-jib crane most directly addresses this?

  1. It uses fewer parts of line so the hook can travel faster
  2. It can raise its jib to a steep angle, reducing swept radius and keeping the jib clear of obstacles Correct answer.
  3. It does not require a counter-jib or counterweights
  4. It has a longer jib than a trolley crane of the same capacity

Explanation

A luffing-jib crane changes radius by raising and lowering the jib rather than by a trolley, so the jib can be steepened to reduce its swept radius and avoid obstructions such as neighbouring buildings or other cranes. This is why luffing cranes are chosen for congested or over-sailing-sensitive sites.

Question 29Tower Crane Types, Components, and Configuration

A crane's jib is being assembled on the ground before lifting into place. Which configuration detail determines the maximum number of parts of line that can be used for a given hook load?

  1. The colour coding of the hoist rope
  2. The number of sheaves in the hook block and the rope's rated capacity Correct answer.
  3. The length of the counter-jib
  4. The slewing speed setting

Explanation

The number of parts of line is limited by the sheaves available in the hook block and by the rated capacity of the hoist rope and drum. The reeving arrangement must match the load chart's permitted parts of line for the lift.

Question 30Tower Crane Types, Components, and Configuration

An engineer is analysing why a top-slewing crane's jib and counter-jib are configured with the counter-jib shorter than the jib but carrying heavy counterweights. What is the main reason for this arrangement?

  1. To increase the maximum working radius beyond the jib length
  2. To balance the jib's overturning moment with a shorter lever arm and greater mass, keeping the slewing radius compact Correct answer.
  3. To reduce the total crane weight so the mast can be lighter
  4. To eliminate the need for a slewing ring

Explanation

Moment balance is achieved by placing large mass on a shorter counter-jib so its moment roughly offsets the jib's moment, while keeping the overall slewing envelope compact. This reduces the overturning moment the mast and foundation must resist compared with a long, lightly loaded counter-jib.

Question 31Site Preparation, Erection, Climbing, and Dismantling

Before erecting a tower crane, what is the primary purpose of verifying the ground bearing pressure against the crane's foundation design?

  1. To determine the color coding required for the crane's jib
  2. To ensure the foundation will not settle or fail under the crane's loads Correct answer.
  3. To confirm the crane can be assembled within the scheduled time
  4. To calculate the wind speed at which the crane may operate

Explanation

Ground bearing pressure must be compared against the soil's capacity and the foundation design so the crane's base does not settle or fail under dead, live, and moment loads. Settlement or bearing failure can overturn the crane, so this check is fundamental to safe erection.

Question 32Site Preparation, Erection, Climbing, and Dismantling

During crane erection, the manufacturer's erection manual specifies a minimum out-of-service wind speed. What does this limit protect against?

  1. Excessive jib deflection during lifting operations
  2. Loss of stability or structural overload while the crane is partially assembled Correct answer.
  3. Overheating of the hoist motor during climbing
  4. Premature wear of the slewing ring bearings

Explanation

A partially erected crane has reduced stability and structural redundancy, so erection must stop when wind speeds reach the manual's limit. Exceeding it risks overturning or overstressing components before the crane is fully assembled.

Question 33Site Preparation, Erection, Climbing, and Dismantling

What is the function of the climbing frame (climbing cage) during a tower crane climbing operation?

  1. It counterweights the jib during pick-and-carry lifts
  2. It houses the operator's cab during normal operation
  3. It guides and supports the slewing unit as it is raised around the mast Correct answer.
  4. It anchors the crane's tie bars to the building structure

Explanation

The climbing frame surrounds the mast and supports the upper works while a new mast section is inserted and the crane is jacked upward. It provides the guided, temporary support needed during the climb.

Question 34Site Preparation, Erection, Climbing, and Dismantling

Which document must be consulted to determine the correct sequence and torque values for bolting mast sections together?

  1. The crane operator's logbook
  2. The local weather forecast
  3. The manufacturer's erection and instruction manual Correct answer.
  4. The site's daily lift plan

Explanation

Mast bolt torque values and tightening sequences are manufacturer-specific and are given in the erection manual. Following them ensures the splice develops its designed strength.

Question 35Site Preparation, Erection, Climbing, and Dismantling

What is the purpose of ballast on a tower crane's counterjib?

  1. To increase the maximum hoist line speed
  2. To reduce the crane's overall height requirement
  3. To balance the moment created by the jib and lifted load Correct answer.
  4. To provide electrical grounding for the crane

Explanation

Ballast counterbalances the overturning moment produced by the jib and the load so the crane remains stable. Incorrect ballast can cause instability in either direction, which is why the manual specifies exact amounts.

Question 36Site Preparation, Erection, Climbing, and Dismantling

When dismantling a tower crane, at what point should the tie bars to the building be removed?

  1. Before any jib sections are removed
  2. Only after the crane has been lowered below the tie attachment level, per the manual Correct answer.
  3. At the same time as the counterweights are released
  4. Immediately after the hook block is removed

Explanation

Ties provide stability to the mast and must remain until the dismantling sequence reaches the point specified by the manufacturer, typically when the crane is lowered below the tie level. Removing ties early can leave the mast unstable.

Question 37Site Preparation, Erection, Climbing, and Dismantling

What is the purpose of a pre-erection site survey for a tower crane?

  1. To calculate the crane's hourly operating cost
  2. To determine the color of the crane's paint finish
  3. To select the crane operator's shift pattern
  4. To confirm clearances, underground services, and access for the erection crane Correct answer.

Explanation

A site survey identifies obstructions, underground utilities, adjacent structures, and access routes so the crane can be positioned and erected safely. It prevents clashes and foundation damage during assembly.

Question 38Site Preparation, Erection, Climbing, and Dismantling

A crane is being erected adjacent to a public footpath. Which control best manages the risk of falling components during assembly?

  1. Removing the tie bars to reduce the crane's footprint
  2. Establishing an exclusion zone with barriers and a trained marshal Correct answer.
  3. Increasing the hoist speed to shorten the erection time
  4. Lowering the out-of-service wind limit to zero

Explanation

An exclusion zone keeps people out of the drop zone, and a marshal enforces it during the higher-risk assembly phase. This directly controls the consequence of falling objects.

Question 39Site Preparation, Erection, Climbing, and Dismantling

During a climbing operation, the hydraulic system loses pressure momentarily. What is the correct immediate action?

  1. Continue climbing and monitor the pressure gauge
  2. Increase engine speed to restore pressure faster
  3. Lower the entire crane to the ground and restart
  4. Stop the climb, secure the load with mechanical locks, and investigate before proceeding Correct answer.

Explanation

A loss of hydraulic pressure during climbing is a serious event; the climb must stop and the upper works secured with the mechanical locking devices before any diagnosis. Continuing risks uncontrolled descent of the climbing assembly.

Question 40Site Preparation, Erection, Climbing, and Dismantling

Why must the crane's jib be positioned in the manufacturer-specified out-of-service orientation when work stops?

  1. To minimize the moment arm and allow the crane to weathervane safely in wind Correct answer.
  2. To reduce fuel consumption overnight
  3. To allow the hoist rope to be removed
  4. To make the operator's cab more accessible

Explanation

The out-of-service position reduces wind loading and permits the crane to slew freely (weathervane) so it presents the least resistance to storm winds. This protects the crane from excessive wind-induced moments.

Question 41Site Preparation, Erection, Climbing, and Dismantling

A tower crane is to be tied to a concrete structure. What must be verified before the tie is loaded?

  1. That the jib has been fully assembled
  2. That the operator has completed a refresher course
  3. That the crane's paint is fully cured
  4. That the concrete has reached the strength assumed in the tie design Correct answer.

Explanation

Tie loads are transferred into the structure, so the concrete must have attained the design strength assumed by the tie engineer before loading. Loading immature concrete can cause pull-out or structural damage.

Question 42Site Preparation, Erection, Climbing, and Dismantling

When selecting the mobile crane for erecting a tower crane, which combination must be checked against the lift plan?

  1. Boom length only
  2. Load weight, radius, boom configuration, and ground conditions Correct answer.
  3. Operator's seniority and crane color
  4. Hoist rope diameter alone

Explanation

The mobile crane's capacity depends on the interaction of load weight, working radius, boom configuration, and ground support. All must be checked against the lift plan to ensure the lift is within capacity.

Question 43Site Preparation, Erection, Climbing, and Dismantling

What is the primary reason for torque-checking mast bolts after the first few days of service following erection?

  1. To reduce the crane's lifting capacity
  2. To allow the crane to be repainted
  3. To change the bolts to a different grade
  4. To confirm the bolts have not relaxed or settled under initial load Correct answer.

Explanation

Newly assembled joints can settle and bolts can relax under initial service loads, so a re-torque check confirms the splice retains its designed clamping force. This is typically required by the manufacturer's manual.

Question 44Site Preparation, Erection, Climbing, and Dismantling

During dismantling, the counterweights are removed in a specified order. Why is the order critical?

  1. To allow the jib to be painted
  2. To reduce the noise generated on site
  3. To keep the crane balanced within the stability limits at each stage Correct answer.
  4. To speed up the dismantling process

Explanation

Removing counterweights changes the crane's balance, so the manual specifies an order that keeps the remaining structure within stability limits at every stage. Removing them out of order can cause the crane to tip.

Question 45Site Preparation, Erection, Climbing, and Dismantling

A climbing operation is planned on a windy day. The measured wind speed is at the manual's climbing limit. What is the appropriate decision?

  1. Stop climbing because the limit has been reached and gusts may exceed it Correct answer.
  2. Increase the climb rate to finish before gusts arrive
  3. Proceed because the limit has not been exceeded
  4. Proceed only if the load is light

Explanation

Climbing limits are maximums, and gusts can push instantaneous speeds above the measured average. Reaching the limit means the operation should stop because there is no margin for gusting.

Question 46Site Preparation, Erection, Climbing, and Dismantling

Why is a trial lift of a mast section recommended before the full erection lift?

  1. To test the tower crane's hoist brake
  2. To verify the color match of the mast sections
  3. To warm up the mobile crane's engine
  4. To confirm the rigging, balance, and crane capacity before committing to the full lift Correct answer.

Explanation

A trial lift verifies that the load is balanced, the rigging is correct, and the mobile crane has adequate capacity at the actual radius. It reveals problems while the load is still low and controlled.

Question 47Site Preparation, Erection, Climbing, and Dismantling

What is the role of a permit-to-work system during tower crane erection?

  1. To replace the need for a trained erection team
  2. To formally authorize the task with defined controls, isolations, and sign-offs Correct answer.
  3. To set the crane's lifting capacity
  4. To determine the crane's purchase price

Explanation

A permit-to-work records that hazards have been assessed and controls, isolations, and authorizations are in place before high-risk work starts. It provides a formal checkpoint and audit trail.

Question 48Site Preparation, Erection, Climbing, and Dismantling

A crane is to be erected near overhead power lines. Which control is most appropriate before erection begins?

  1. Rely on the mobile crane operator to keep clear
  2. Isolate or divert the lines, or establish a documented safe clearance with barriers Correct answer.
  3. Reduce the crane's load chart by half
  4. Erect the crane at night when lines are less visible

Explanation

The preferred control is to isolate or divert the lines; if that is not possible, a documented safe clearance with physical barriers and goalposts must be established. Relying on operator judgment alone is not an adequate control.

Question 49Site Preparation, Erection, Climbing, and Dismantling

During a climbing operation, what is the purpose of the guide rollers on the climbing frame?

  1. To maintain mast alignment and control lateral movement as the crane is jacked Correct answer.
  2. To drive the slewing motion of the crane
  3. To cool the hydraulic cylinders
  4. To tension the hoist rope

Explanation

Guide rollers keep the climbing assembly aligned with the mast and restrain lateral movement during jacking, which is essential for controlled climbing. Misadjusted rollers can cause binding or loss of alignment.

Question 50Site Preparation, Erection, Climbing, and Dismantling

A crane's foundation design assumes a specific concrete strength at the time of erection. The pour is two days old. What should be done?

  1. Erect the crane and monitor for settlement afterward
  2. Proceed with erection because the crane is light
  3. Add extra ballast to compensate for weak concrete
  4. Verify concrete strength by testing or curing records before loading the foundation Correct answer.

Explanation

The foundation must have attained the strength assumed in its design before crane loads are applied. Strength should be verified by test results or curing records rather than assumed from age alone.