RB Spreader Bars and Lifting Beams 2

Question 1

How does a lifting beam differ structurally from a spreader bar?

Accepted Answer

A lifting beam resists bending moments; a spreader bar resists compression

Answer

A lifting beam is made of aluminium; a spreader bar is always made of steel

Answer

A lifting beam is used only overhead; a spreader bar is used at ground level

Answer

A lifting beam has a fixed SWL; a spreader bar's SWL varies with configuration

Question 2

As the sling angle measured from vertical increases beyond 45 degrees when used with a spreader bar, what happens to the compressive force in the bar?

Accepted Answer

The compressive force increases significantly

Answer

The compressive force decreases as the slings become more spread out

Answer

The compressive force remains constant regardless of sling angle

Answer

The compressive force reverses and becomes tensile

Question 3

Under which circumstance must a spreader bar be immediately removed from service?

Accepted Answer

When visible cracks, deformation, or missing/illegible SWL markings are found

Answer

When it has been used more than 100 times in a 12-month period

Answer

When the rigging configuration changes between consecutive lifts

Answer

When the ambient temperature on site exceeds 30°C

Question 4

Which Australian standard specifically covers the design and use of lifting devices such as spreader bars and lifting beams?

Accepted Answer

AS 4991 (Lifting devices)

Answer

AS/NZS 3000 (Wiring Rules)

Answer

AS 1576 (Scaffolding)

Answer

AS 3569 (Steel wire ropes)

Question 5

If a spreader bar's test certificate cannot be located on site, what must the rigger do?

Accepted Answer

Not use the spreader bar until a valid certificate is produced

Answer

Proceed with the lift at 50% of the marked SWL as a precaution

Answer

Obtain verbal confirmation of the SWL from the site supervisor

Answer

Use the bar only for loads under 1 tonne regardless of the markings

Question 6

Where should the crane hook attach when a spreader bar is rigged for a standard lift?

Accepted Answer

To the central lifting lug or pick point on top of the spreader bar

Answer

To one end of the spreader bar to keep the hook centred over the load

Answer

Directly to the load's slings, bypassing the bar entirely

Answer

To the slings at mid-span between the bar and the load

Question 7

What is the function of end retention pins or end stops on a spreader bar?

Accepted Answer

To prevent slings from sliding off the end fittings during the lift

Answer

To adjust the rated SWL of the bar for different load weights

Answer

To indicate the maximum safe extension length of the bar

Answer

To connect the spreader bar directly to the crane's main hook block