A motor carrier is securing a bundle of structural steel pipes on an open flatbed trailer.… — Commercial Driver's License (CDL) General Knowledge Exam

A motor carrier is securing a bundle of structural steel pipes on an open flatbed trailer. The cargo measures $27\text{ feet}$ in length, weighs $38{}000\text{ pounds}$ , and is not blocked against a front-end headboard. The driver secures the load using indirect synthetic webbing straps that pass over the cargo to anchor points on both sides of the trailer, each rated with a Working Load Limit (WLL) of $4{}000\text{ pounds}$ . What is the minimum number of these tie-down straps required to satisfy federal cargo securement standards?

A
$3\text{ straps}$
B
$4\text{ straps}$
$5\text{ straps}$ Cevap
D
$2\text{ straps}$

Cevap

5\text{ straps}

are required to satisfy both the aggregate Working Load Limit and length rules.

Federal regulations dictate that aggregate Working Load Limit (WLL) must equal at least 50% of the total cargo weight. For a

38{}000\text{-pound}

load, the required aggregate WLL is

19{}000\text{ pounds}

. Dividing

19{}000\text{ pounds}

by the

4{}000\text{-pound}

rating of each indirect strap yields 4.75, which rounds up to 5 straps (

20{}000\text{ pounds}

total WLL). Because 5 straps also exceeds the length-based securement requirement for a

27\text{-foot}

load, 5 straps is the correct minimum.

Adım Adım Çözüm

Calculate the required aggregate Working Load Limit (WLL) based on cargo weight

\text{Required WLL} = 0.50 \times 38{}000\text{ lbs} = 19{}000\text{ lbs}

Federal safety standards require that the aggregate WLL of all securement devices must equal at least 50% (one-half) of the total weight of the cargo.

Determine the number of straps needed to satisfy the weight requirement

\frac{19{}000\text{ lbs}}{4{}000\text{ lbs/strap}} = 4.75 \rightarrow 5\text{ straps}

Because indirect tie-downs passing over the top of the cargo contribute 100% of their WLL, 5 straps provide

5 \times 4{}000\text{ lbs} = 20{}000\text{ lbs}

of aggregate WLL, which satisfies the

19{}000\text{-pound}

requirement.

Verify compliance with length-based minimum tie-down rules

Length requirement is satisfied (a

27\text{-foot}

unblocked load requires a minimum of 3 to 4 tie-downs; 5 straps exceeds this minimum).

Commercial motor vehicle drivers must meet whichever regulatory requirement (length-based or weight-based) demands the greater number of tie-downs.

Anahtar Kavram

Cargo securement aggregate Working Load Limit (WLL) and tie-down count rules

Tahmini Süre:1m 30s

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