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 designed to resist bending (flexural) forces from loads suspended below it, while a spreader bar is designed to resist compressive forces from inward-pulling slings.

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

As sling angles increase beyond 45° from vertical, the horizontal component of sling forces grows rapidly, driving up the compressive load on the spreader bar.

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

Visible cracks, deformation, or missing/illegible SWL markings indicate compromised structural integrity, requiring immediate removal from service.

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 4991 (Lifting devices) is the Australian standard specifically covering the design, manufacture, testing, and safe use of lifting devices including spreader bars and lifting beams.

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

Without a valid test certificate, the spreader bar's design and rated SWL cannot be verified, so it must not be used until proper documentation is produced.

Rigging Licence Practice Test

Rigging Licence Practice Test

RB Spreader Bars and Lifting Beams 2