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High Risk Work Licence - Tower Crane (CT) study materials
High Risk Work Licence - Tower Crane (CT) study resources

High Risk Work Licence - Tower Crane (CT) practice questions

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Question 1Legislative and regulatory requirements, duty of care and licensing obligations

Under the model WHS Regulations, what must a person conducting a business or undertaking (PCBU) hold before operating a tower crane as a licensed high risk work activity?

  1. A written reference from a crane supplier
  2. A certificate of registration for the crane
  3. A current high risk work licence for tower crane operation Correct answer.
  4. A general construction induction card only

Explanation

Tower crane operation is a class of high risk work, so the PCBU must ensure the operator holds a current high risk work licence for that class. The general induction card is a separate basic safety requirement and does not authorise high risk work. Registration of plant and supplier references do not substitute for a licence.

Question 2Legislative and regulatory requirements, duty of care and licensing obligations

A tower crane operator's high risk work licence is approaching its expiry date. What is the operator's obligation?

  1. Ask the site supervisor to sign off interim authority
  2. Stop operating only after a regulator inspection occurs
  3. Renew or apply for a new licence before the expiry date to keep working lawfully Correct answer.
  4. Continue operating while the renewal paperwork is being processed

Explanation

A high risk work licence is time-limited, and the holder must renew it through the regulator before it lapses to remain authorised. Working on an expired licence is an offence regardless of whether paperwork is in progress. A supervisor cannot grant interim authority to perform licensed work.

Question 3Legislative and regulatory requirements, duty of care and licensing obligations

What is the primary duty of a person conducting a business or undertaking under WHS law?

  1. To transfer all safety responsibility to the crane operator
  2. To eliminate or minimise risks to health and safety so far as is reasonably practicable Correct answer.
  3. To maximise productivity while staying within the project budget
  4. To follow only the manufacturer's instructions regardless of site conditions

Explanation

The primary duty requires the PCBU to ensure health and safety so far as is reasonably practicable, which means weighing likelihood and severity of harm against the cost and difficulty of controls. Responsibility cannot be shifted entirely onto workers. Manufacturer guidance is one input but does not override the general duty.

Question 4Legislative and regulatory requirements, duty of care and licensing obligations

What does the term 'reasonably practicable' require a duty holder to consider?

  1. The likelihood and severity of harm weighed against the cost and difficulty of available controls Correct answer.
  2. Only whether an incident has previously occurred
  3. The preferences of the crane manufacturer's sales representative
  4. Only the cost of the control measures proposed

Explanation

Reasonably practicable involves balancing the likelihood and degree of harm against what is known about the hazard and the availability, suitability and cost of ways to remove or reduce the risk. Cost alone is never decisive. Past incidents are relevant evidence but are not the test.

Question 5Legislative and regulatory requirements, duty of care and licensing obligations

A worker is directed to operate a tower crane but holds a licence for a different high risk work class. What should the worker do?

  1. Refuse to operate and notify the supervisor that the task is outside the licence class Correct answer.
  2. Operate after signing an internal competency declaration
  3. Operate the crane slowly while supervised by a licensed colleague
  4. Operate only for short lifts under five minutes

Explanation

A licence authorises work only in the classes it covers, and a worker must not perform high risk work outside those classes. The correct response is to decline the task and escalate it so a licensed operator can be arranged. Supervision, task duration and internal declarations do not create legal authority.

Question 6Legislative and regulatory requirements, duty of care and licensing obligations

Who is responsible for ensuring that a tower crane is inspected and maintained in safe working order on a construction site?

  1. The nearest trade contractor working under the crane
  2. The person conducting the business or undertaking with management or control of the plant Correct answer.
  3. The crane operator alone, as the person using the equipment
  4. The crane manufacturer, regardless of the plant's age

Explanation

The PCBU with management or control of the plant must ensure it is inspected, maintained and repaired so it is without risks to health and safety. Operators contribute by conducting pre-start checks but do not carry the whole maintenance duty. Manufacturers have design obligations, not ongoing site maintenance duties.

Question 7Legislative and regulatory requirements, duty of care and licensing obligations

A tower crane erector is assembling a crane. Which statement best describes the licensing requirement for the erecting work?

  1. Erection is unregulated provided an engineer supervises
  2. Any licensed tower crane operator may perform the erection without further qualification
  3. Erection requires only a working at heights certificate
  4. The erecting work is itself high risk work that requires the relevant licence class Correct answer.

Explanation

Erecting a tower crane is a separate class of high risk work from operating it, so a person must hold the licence for that erection class. Holding an operator licence does not authorise assembly or dismantling. Other tickets and engineering supervision do not replace the required licence.

Question 8Legislative and regulatory requirements, duty of care and licensing obligations

What is the main purpose of a safe work method statement (SWMS) for high risk construction work involving a tower crane?

  1. To document how the high risk work will be carried out and the controls that will be applied Correct answer.
  2. To serve as the crane's maintenance logbook
  3. To record the crane's purchase price and depreciation schedule
  4. To replace the need for operator licensing on site

Explanation

A SWMS sets out the high risk construction work, the hazards, and the risk controls, and must be followed and reviewed as conditions change. It supports planning and supervision but does not displace licensing or maintenance obligations. Financial records and maintenance logs serve entirely different purposes.

Question 9Legislative and regulatory requirements, duty of care and licensing obligations

A crane operator notices a colleague operating a tower crane while apparently impaired by alcohol. What is the most appropriate action under WHS duties?

  1. Ignore it because reporting could damage workplace relationships
  2. Intervene to stop the work and report the concern through the site's safety process Correct answer.
  3. Take a photograph and post it to a site chat group
  4. Wait until the shift ends and mention it informally

Explanation

Workers must take reasonable care for their own and others' safety and follow reasonable instructions, which includes acting on an imminent risk. Stopping the task and reporting through established channels allows the PCBU to respond and remove the risk. Delaying or ignoring the hazard leaves a serious risk uncontrolled.

Question 10Legislative and regulatory requirements, duty of care and licensing obligations

What does the duty to consult with workers require of a PCBU when changes affect tower crane operations?

  1. Delegating the consultation to the crane operator's union only
  2. Informing workers of decisions only after they have been implemented
  3. Sharing relevant information and giving workers a reasonable opportunity to express views before decisions are made Correct answer.
  4. Consulting only the crane manufacturer's representative

Explanation

Consultation requires the PCBU to share information about the matter, give workers a reasonable opportunity to express views, and take those views into account before deciding. It is not merely post-decision notification. Consultation must reach the workers affected, not only external parties.

Question 11Legislative and regulatory requirements, duty of care and licensing obligations

A tower crane is registered plant in the jurisdiction. What does registration primarily confirm?

  1. That the operator is competent to use the crane
  2. That the site has adequate insurance cover
  3. That the plant design and item have been registered with the regulator as required Correct answer.
  4. That the crane will never require further inspection

Explanation

Plant registration is an administrative process confirming that the design and the individual item are recorded with the regulator as required by the regulations. It says nothing about operator competence or ongoing inspection frequency. Insurance is a commercial matter unrelated to plant registration.

Question 12Legislative and regulatory requirements, duty of care and licensing obligations

A principal contractor wants to shorten the crane's inspection interval because of heavy use. How should this decision be handled?

  1. Let the operator decide each day whether an inspection is needed
  2. Rely on the crane's onboard alarms instead of inspections
  3. Document the revised interval through a risk-based review and ensure competent persons carry out the inspections Correct answer.
  4. Keep the original interval because inspection frequency can never be changed

Explanation

Inspection intervals can be adjusted where a documented risk assessment shows the plant is subject to more demanding conditions, provided competent persons perform the inspections. The change must be justified and recorded rather than left to informal judgement. Onboard alarms supplement but do not replace inspection.

Question 13Legislative and regulatory requirements, duty of care and licensing obligations

An operator's high risk work licence is suspended by the regulator following a safety incident. What is the effect on the operator's authority to work?

  1. The operator may continue working if the employer gives written permission
  2. The operator must not perform tower crane work until the suspension is lifted Correct answer.
  3. The operator may work only on sites outside the regulator's jurisdiction
  4. The operator may continue if a colleague co-signs the lift plan

Explanation

A suspended licence removes the holder's authority to perform the licensed work for the duration of the suspension. An employer cannot override a regulator's decision by granting permission. Working during suspension exposes both the operator and the PCBU to enforcement action.

Question 14Legislative and regulatory requirements, duty of care and licensing obligations

Which situation best illustrates the principle that WHS duties cannot be transferred to another party?

  1. A PCBU delegates site induction to the crane operator
  2. A PCBU engages a crane contractor but still must ensure, so far as is reasonably practicable, that the crane operations are safe Correct answer.
  3. A PCBU asks the crane contractor to hold all licences on its behalf
  4. A PCBU includes a safety clause in the crane hire contract and then relies on it entirely

Explanation

WHS duties are non-delegable, so a PCBU that engages contractors retains its own duty to ensure safety so far as is reasonably practicable. Contractual clauses can allocate commercial responsibility but cannot extinguish the statutory duty. Relying solely on a contractor or worker to discharge the duty is not sufficient.

Question 15Legislative and regulatory requirements, duty of care and licensing obligations

What must a person do to obtain a high risk work licence for tower crane operations?

  1. Complete the required training and assessment with a registered training provider and apply to the regulator Correct answer.
  2. Pay the crane hire company a registration fee and start work
  3. Complete a site-specific induction and begin supervised operation
  4. Have five years of general construction experience

Explanation

Obtaining a high risk work licence requires training and assessment against the relevant competency standard through a registered training organisation, followed by an application to the regulator. Site induction and general experience do not confer a licence. Payments to a hire company have no licensing effect.

Question 16Legislative and regulatory requirements, duty of care and licensing obligations

A tower crane operator is asked to operate a crane fitted with a different control configuration from the one used during training. What is the appropriate response?

  1. Refuse permanently because control differences are unmanageable
  2. Seek familiarisation and instruction on the specific crane before operating it Correct answer.
  3. Ask a colleague to operate the crane while the operator watches
  4. Operate immediately because the licence covers all tower cranes

Explanation

A licence authorises the class of plant but does not replace the need for familiarisation with the particular crane and its controls. The PCBU must provide information, training and instruction so the operator can work safely. Immediate operation without familiarisation or permanent refusal are both inappropriate responses.

Question 17Hazard identification, risk assessment and control for tower crane operations

Before a tower crane is erected on a site, which document should identify the crane's maximum rated capacity at each radius and the wind speed at which operations must stop?

  1. The crane's load chart and manufacturer's operating manual Correct answer.
  2. The concrete delivery dockets for the footings
  3. The site induction attendance register
  4. The subcontractor's public liability certificate

Explanation

The load chart and manufacturer's manual are the authoritative sources of rated capacity at each radius and of the maximum permissible wind speed for operation. These documents must be available to the crane operator and riggers and are used to plan every lift. Other site paperwork does not define the crane's engineering limits.

Question 18Hazard identification, risk assessment and control for tower crane operations

A tower crane is to be sited next to a proposed high-rise. Which factor most directly determines the crane's required hook height and jib length?

  1. The final building height and the reach needed to cover the load pickup and set-down points Correct answer.
  2. The distance from the site office to the nearest public road
  3. The colour scheme required by the client's branding guidelines
  4. The number of workers expected on site at peak times

Explanation

Hook height must clear the finished structure and any obstructions, while jib length must reach every required pickup and placement point within rated capacity. These geometric requirements drive the crane selection and siting study. Branding, workforce numbers and road distance do not govern crane geometry.

Question 19Hazard identification, risk assessment and control for tower crane operations

What is the primary purpose of a crane lift study prepared before crane erection?

  1. To identify lift masses, radii, rigging and hazards so each lift can be planned within capacity Correct answer.
  2. To document the crane's service history with the previous owner
  3. To calculate the payroll allowances for rigging crews
  4. To record the operator's daily start-up checks after the shift begins

Explanation

A lift study analyses each planned lift for mass, radius, rigging arrangement and environmental hazards so the task can be engineered to stay within rated capacity. It is a planning document produced before work starts. Daily checks, payroll and service history are separate matters.

Question 20Hazard identification, risk assessment and control for tower crane operations

During a lift, a rigger notices the load begin to swing toward a public footpath beyond the hoarding. What is the most appropriate immediate control?

  1. Ask a bystander to hold the load steady with a guide rope from outside the hoarding
  2. Stop the lift and lower the load under control before reassessing the exclusion zone Correct answer.
  3. Continue the lift quickly so the load clears the footpath sooner
  4. Signal the operator to increase slewing speed to steady the load

Explanation

When a load moves outside the planned controlled area, the lift must be stopped and the load lowered under control before anything else happens. The exclusion zone and lift plan are then reviewed to prevent recurrence. Speeding up or involving the public increases the risk of a serious incident.

Question 21Hazard identification, risk assessment and control for tower crane operations

Which condition makes a tower crane lift a 'complex' or high-risk lift requiring a documented, engineered lift plan?

  1. The operator has more than ten years of experience
  2. The load is near the crane's rated capacity at that radius or is a tandem or unusual-shape lift Correct answer.
  3. The load is a pallet of bricks lifted to the second floor
  4. The lift occurs on a weekday morning with light wind

Explanation

Lifts near rated capacity, tandem lifts and loads with unusual geometry or wind area demand engineering assessment and a specific documented plan. Routine lifts of standard materials within capacity are covered by standard procedures. Operator experience and time of day do not by themselves make a lift complex.

Question 22Hazard identification, risk assessment and control for tower crane operations

What is the main reason for maintaining a documented exclusion zone beneath and around a tower crane's slewing arc?

  1. To reserve parking space for the crane crew's vehicles
  2. To reduce the amount of paperwork required for the lift
  3. To keep people out from under suspended loads and away from the crane's operating radius Correct answer.
  4. To prevent the crane's counterweight from being painted

Explanation

An exclusion zone physically separates people from the drop zone and the slewing arc, which are the areas of greatest consequence if a load or rigging fails. It is a primary engineering and administrative control for crane operations. Parking, aesthetics and paperwork reduction are not safety justifications.

Question 23Hazard identification, risk assessment and control for tower crane operations

A tower crane's maximum in-service wind speed is exceeded during a lift. What is the correct action?

  1. Increase the hoist speed so the lift is completed before the wind rises further
  2. Cease lifting, lower the load if safe to do so, and place the crane in the specified out-of-service condition Correct answer.
  3. Continue lifting but reduce the load mass by half
  4. Ask the dogger to stand on the load to steady it against the wind

Explanation

Operations must stop once the manufacturer's in-service wind limit is reached, and the crane must be placed in the specified out-of-service condition, such as free-slewing with the jib aligned to the prevailing wind. Reducing load or hurrying does not remove the wind hazard. Personnel must never ride or stand on a load.

Question 24Hazard identification, risk assessment and control for tower crane operations

Which of the following best describes the purpose of a crane's anemometer and its associated alarm?

  1. To detect nearby aircraft in controlled airspace
  2. To measure the load's mass during the hoist
  3. To record the crane's slewing angle for the daily log
  4. To measure wind speed at height and warn the operator when limits are approached or exceeded Correct answer.

Explanation

An anemometer measures wind speed at the crane's height, where wind can be significantly stronger than at ground level, and triggers a warning as limits are approached. This allows the operator to stop safely before control is lost. Mass, slew angle and aircraft detection are handled by other systems.

Question 25Hazard identification, risk assessment and control for tower crane operations

A mobile crane is to operate inside the slewing radius of an operating tower crane. What is the key control before work begins?

  1. A documented coordination plan with defined communication, separation of arcs and a nominated person controlling both operations Correct answer.
  2. An instruction to the tower crane operator to work faster to avoid overlap
  3. A verbal agreement between the two operators on the morning of the lift
  4. A promise that the mobile crane will work only at lunchtime

Explanation

Where cranes share airspace, a documented coordination plan must define the operating sequence, communication method, physical separation and who has authority to stop work. This prevents collision of jibs, loads or rigging. Verbal arrangements and timing tricks are unreliable controls.

Question 26Hazard identification, risk assessment and control for tower crane operations

What is the main hazard created by erecting a tower crane close to overhead power lines?

  1. Faster wear on the crane's hoist rope
  2. Increased noise levels from the crane's slewing motor
  3. Reduced visibility of the load due to shadow from the lines
  4. Contact or arcing between the crane or its load and live conductors, causing electrocution Correct answer.

Explanation

The dominant hazard is electrical contact or arcing between the crane structure, rope or load and energised conductors, which can be fatal. Controls include approach distances set by the electricity supply authority, exclusion zones and, where required, isolation. Noise, shadow and rope wear are not the primary risk.

Question 27Hazard identification, risk assessment and control for tower crane operations

A crane's load moment indicator alarms during a lift. What does this indicate and what should the operator do?

  1. The hoist rope is too short, so the operator should lower the hook
  2. The load moment is approaching or exceeding the rated limit, so the lift should be stopped and the radius or load reduced Correct answer.
  3. The slew brake needs adjustment, so the operator should keep slewing
  4. The hydraulic oil temperature is too high, so the crane should idle for an hour

Explanation

The load moment indicator compares actual load moment with the rated value for the current radius and alarms as the limit is approached or exceeded. The operator must stop and reduce the load or radius before continuing. It does not monitor oil temperature, brakes or rope length.

Question 28Hazard identification, risk assessment and control for tower crane operations

Why must the counterweight of a tower crane be treated as a hazard even when no load is being lifted?

  1. It must be removed before every lift
  2. Its slewing path sweeps a large area at height and can strike people or structures Correct answer.
  3. It only moves when the hoist is operated
  4. It generates electromagnetic radiation during slewing

Explanation

The counterweight swings on the opposite side of the slew and its path can strike people, plant or structures within the crane's radius. The area beneath and around the counterweight path must be included in the exclusion zone. It does not emit radiation, is not removed for lifts and slews with the jib.

Question 29Hazard identification, risk assessment and control for tower crane operations

Which control best addresses the risk of a load being dropped because of a rigging failure?

  1. Painting the slings in a high-visibility colour
  2. Competent riggers, inspected and rated slings, and verification of the rigging before each lift Correct answer.
  3. Placing a spotter at the site gate
  4. Asking the crane operator to hoist slowly

Explanation

Rigging failures are controlled by using competent riggers, correctly rated and inspected slings, and a verified rigging arrangement before each lift. These measures address the integrity of the load path directly. Colour, hoist speed and a gate spotter do not prevent sling failure.

Question 30Hazard identification, risk assessment and control for tower crane operations

A crane is being used to lift a large precast panel with a high surface area. Which environmental factor most increases the risk during this lift?

  1. Air temperature falling below twenty degrees
  2. Ambient noise from the concrete pump
  3. Ground-level dust reducing visibility at the site gate
  4. Wind acting on the panel's large area, increasing swing and reducing control Correct answer.

Explanation

Loads with large surface area catch the wind, which increases swing, rotation and the effective load on the crane. The lift must be planned for the forecast wind and stopped when limits are reached. Noise, dust and moderate temperature changes do not materially affect the panel's behaviour in the air.

Question 31Hazard identification, risk assessment and control for tower crane operations

What should be done if the ground conditions at a tower crane's base begin to show settlement or cracking?

  1. Fill the cracks with soil and resume work
  2. Continue operating but reduce the crane's slewing speed
  3. Suspend crane operations and have the foundation and supporting ground assessed by a competent engineer Correct answer.
  4. Add extra counterweight to stabilise the base

Explanation

Settlement or cracking under a crane base indicates possible loss of foundation support, which could lead to catastrophic collapse. Operations must stop immediately and a competent engineer must assess the foundation and ground. Speed reduction, extra counterweight or cosmetic filling do not restore stability.

Question 32Hazard identification, risk assessment and control for tower crane operations

Which of the following is the most reliable way to confirm a load's mass before lifting?

  1. Obtain it from the supplier's documentation or weigh it, and never rely on visual estimation Correct answer.
  2. Assume the crane's capacity indicator will compensate automatically
  3. Ask the newest member of the rigging crew to judge
  4. Estimate it by comparing it to a similar load lifted previously

Explanation

Accurate mass is fundamental to lift planning, so it must come from documentation, marking or direct weighing. Visual estimation is unreliable, particularly for dense materials or when contents are unknown. The capacity indicator warns of overload but does not make an unknown mass safe.

Question 33Hazard identification, risk assessment and control for tower crane operations

What is the purpose of a crane's slew restriction or zoning system on a congested site?

  1. To control the crane's hydraulic oil pressure
  2. To record the operator's hours of work
  3. To limit the maximum load the crane can lift
  4. To limit the area the jib can slew into, preventing collision with structures or other cranes Correct answer.

Explanation

Slew restriction systems electronically limit the arc the jib may enter, protecting structures, neighbouring property and other cranes from collision. They are a physical control that works independently of operator attention. Load limiting, time recording and hydraulic pressure are separate functions.

Question 34Hazard identification, risk assessment and control for tower crane operations

Two workers are guiding a load with tag lines when one line snags on a scaffold. What is the safest response?

  1. Let go of the tag line and walk away without signalling
  2. Pull harder on the tag line to free it while the load remains suspended
  3. Signal the operator to stop and lower the load, then free the line only when the load is landed Correct answer.
  4. Signal the operator to slew faster so the line pulls free

Explanation

A snagged tag line can pull the load, the scaffold or the worker, so the lift must be stopped and the load landed before the line is freed. This removes stored energy and the risk of sudden release. Pulling harder, abandoning the line or slewing faster all increase the danger.

Question 35Hazard identification, risk assessment and control for tower crane operations

Why is free-slewing the specified out-of-service condition for many tower cranes in high winds?

  1. It reduces the crane's power consumption overnight
  2. It locks the jib so wind cannot move it at all
  3. It allows the crane to keep lifting in stronger winds
  4. It allows the jib to align with the wind, reducing the wind load and torsional forces on the mast Correct answer.

Explanation

In free slew the jib weathervanes downwind, minimising the area presented to the wind and reducing the torsional and bending loads on the mast and slewing mechanism. This is why the manufacturer specifies it for high-wind conditions. It does not permit lifting in stronger winds or lock the jib.

Question 36Hazard identification, risk assessment and control for tower crane operations

A crane operator is asked to lift a load that is not on the day's lift plan. What should happen?

  1. The operator lifts it immediately because the crane is already set up
  2. The dogger approves it verbally and the lift proceeds
  3. The load is lifted at reduced height without any planning
  4. The lift is assessed and planned before it proceeds, including mass, radius, rigging and hazards Correct answer.

Explanation

Any lift not covered by the existing plan must be assessed and planned before it proceeds, because mass, radius, rigging and environmental conditions may differ from the planned work. A crane being set up does not make an unplanned lift safe. Verbal approval by a dogger is not an adequate substitute for planning.

Question 37Hazard identification, risk assessment and control for tower crane operations

Which combination best describes a hierarchy-of-control approach to crane hazards?

  1. Eliminate the lift or hazard where possible, then engineer controls, then administrative controls, then PPE Correct answer.
  2. Use warning signs as the primary control and rely on worker vigilance
  3. Rely on PPE first, then training, then signage
  4. Rely on experienced operators to notice hazards and act

Explanation

The hierarchy of control ranks measures from most to least reliable: eliminate the hazard, substitute or engineer it out, then apply administrative controls, with PPE as the last line. Applying this to crane work means designing out lifts and engineering exclusion zones before relying on procedures or PPE. Relying on vigilance or signage alone is the weakest approach.

Question 38Hazard identification, risk assessment and control for tower crane operations

What is the key risk when a tower crane is climbed (jacked) to increase its height?

  1. Loss of stability or structural failure during the climbing process, requiring engineered procedure and exclusion Correct answer.
  2. Increased fuel consumption of the crane's diesel engine
  3. Faster wear of the operator's seat
  4. Reduced radio range for the crane's communication system

Explanation

Climbing introduces temporary conditions in which the crane's stability and structural load paths differ from the completed configuration, so it must follow an engineered procedure with a defined exclusion zone. Fuel use, radio range and seat wear are not the significant risks.

Question 39Hazard identification, risk assessment and control for tower crane operations

What is the primary reason for requiring a pre-operational inspection of a tower crane at the start of each shift?

  1. To measure the crane's fuel level for refuelling
  2. To detect defects or abnormal conditions before the crane is used for lifting Correct answer.
  3. To record the operator's attendance for payroll
  4. To satisfy the crane manufacturer's warranty conditions

Explanation

The pre-operational inspection checks critical items such as ropes, brakes, limiters, alarms and structural condition so that defects are found before lifting begins. It is a safety control, not a warranty, payroll or refuelling task. Defects found must be reported and the crane taken out of service until rectified.

Question 40Hazard identification, risk assessment and control for tower crane operations

A load must be lifted over a live pedestrian walkway that cannot be closed. Which control set is most appropriate?

  1. Reroute the lift or provide a fully covered, engineered protection structure, and stop pedestrian movement during the lift Correct answer.
  2. Use a louder warning siren and continue lifting
  3. Ask pedestrians to look up and walk quickly beneath the load
  4. Lift the load higher so pedestrians feel safer

Explanation

Where people must pass beneath a lift, the preferred control is to reroute the lift or provide engineered overhead protection, combined with stopping pedestrian movement while the load is in transit. Advice to hurry, extra height or louder alarms do not prevent a dropped load from striking people.

Question 41Tower crane types, major components, structural principles and stability

In a tower crane, which component directly counterbalances the load moment produced by the jib and suspended load?

  1. The tower mast base section
  2. The slewing ring assembly
  3. The counter-jib with its counterweights Correct answer.
  4. The trolley and hook block

Explanation

The counter-jib projects opposite the jib and carries counterweights that create an opposing moment about the slewing centre, keeping the crane stable. Stability depends on the counterweight moment always exceeding the overturning moment from the load side within rated capacity.

Question 42Tower crane types, major components, structural principles and stability

A tower crane is described as a 'hammerhead' type. What arrangement does this refer to?

  1. A horizontal jib and counter-jib with a trolley and a catenary tie system Correct answer.
  2. A crane whose jib folds for transport inside the mast
  3. A crane mounted on a rail-mounted portal frame
  4. A pivoting luffing jib raised by rope falls

Explanation

Hammerhead cranes have a fixed horizontal jib and counter-jib, with a trolley travelling along the jib to position the load. The jib is supported by pendant ties from the tower head, which is why the head projects above the slewing plane.

Question 43Tower crane types, major components, structural principles and stability

Why is the tower mast of a large tower crane typically built as a lattice of square or triangular sections rather than a solid tube?

  1. It gives a high strength-to-weight ratio and reduces wind loading area Correct answer.
  2. It is cheaper to paint and inspect than a solid member
  3. It permits the crane to be slewed without a slewing ring
  4. It allows the mast to flex freely under load without any restraint

Explanation

Lattice construction places material where it resists compression and bending, achieving stiffness for relatively low self-weight, and the open profile lets wind pass through, reducing overturning forces. Self-weight matters because it reduces available capacity at radius.

Question 44Tower crane types, major components, structural principles and stability

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

  1. To raise and lower the jib during erection
  2. To permit the superstructure to rotate relative to the mast while carrying vertical, moment and horizontal loads Correct answer.
  3. To support the counterweights independently of the turntable
  4. To brake the hoist drum when the load is held

Explanation

The slewing ring is a large bearing that joins the rotating upper works to the fixed mast, transferring all combined loads while allowing rotation. Its bolts and races are critical inspection points because failure here is catastrophic.

Question 45Tower crane types, major components, structural principles and stability

What is the purpose of the pendant (suspension) ropes or tie bars on a hammerhead tower crane?

  1. To tow the trolley along the jib
  2. To anchor the crane base to the foundation
  3. To support the jib and counter-jib from the tower head in tension Correct answer.
  4. To hoist the load from the hook to the drum

Explanation

Pendants hang from the tower head to points along the jib and counter-jib, carrying them in tension so the jib acts as a supported beam rather than a cantilever. Their tension is set at erection and must not be altered without manufacturer instruction.

Question 46Tower crane types, major components, structural principles and stability

Which statement best describes the load moment of a tower crane?

  1. The vertical force acting on the mast foundation
  2. The product of the suspended load and its horizontal distance from the slewing centre Correct answer.
  3. The maximum wind speed the crane can withstand
  4. The total weight of the crane including counterweights

Explanation

Load moment is load multiplied by radius, so a small load at long radius can produce the same moment as a large load close in. Rated capacity charts are built around this relationship, which is why capacity falls as radius increases.

Question 47Tower crane types, major components, structural principles and stability

What does the term 'free-standing height' mean for a tower crane?

  1. The maximum height the crane can reach without being tied to a building or structure Correct answer.
  2. The height of the hook above the ground at minimum radius
  3. The height of the counter-jib above the slewing ring
  4. The clearance required between the jib and overhead power lines

Explanation

Free-standing height is the unsupported height at which the mast can safely stand, limited by the manufacturer's structural and stability calculations. Beyond it the crane must be tied to a structure or have its base enlarged.

Question 48Tower crane types, major components, structural principles and stability

A crane has a rated capacity of 8 t at 20 m radius and 4 t at 40 m radius. Using the load moment relationship, what load could be lifted at 30 m radius if the capacity curve were a simple constant-moment line?

  1. About 4.0 t
  2. About 5.3 t Correct answer.
  3. About 8.0 t
  4. About 6.0 t

Explanation

Constant moment from the 20 m figure is 8 t times 20 m, equal to 160 t·m, and dividing by 30 m gives about 5.3 t. Real charts include deductions for hook block, rigging and jib deflection, so the true figure would be slightly lower.

Question 49Tower crane types, major components, structural principles and stability

Why must the hook block, slings and other lifting gear be deducted from the gross capacity shown on a tower crane chart?

  1. Rigging weight is accounted for by the counterweights
  2. Rigging is only counted when lifting near the jib tip
  3. The chart already deducts rigging and only the payload remains
  4. The chart's rated capacity is a gross figure that includes all suspended equipment Correct answer.

Explanation

Rated capacity is the total load the crane may suspend, so the mass of hook block, slings and shackles reduces the payload that can be lifted. Exceeding this by ignoring rigging weight overloads the crane even when the payload alone looks compliant.

Question 50Tower crane types, major components, structural principles and stability

A luffing jib tower crane is being used on a congested site where the crane must not overfly neighbouring property. Why is a luffing jib often chosen?

  1. The luffing jib can be operated without a slewing ring
  2. The luffing jib eliminates the need for counterweights entirely
  3. The luffing jib has a higher rated capacity than any hammerhead crane
  4. The jib can be raised steeply to reduce its operating radius and keep the load within the site Correct answer.

Explanation

A luffing jib changes radius by altering jib angle rather than running a trolley, so it can be raised to near-vertical and avoid sweeping over adjacent land. This makes it suited to tight urban sites with overfly restrictions.