Examkin

Soru

Zorluk: Çok zorCargo Securement: Blocking and Bracing

A dry van trailer is loaded with an 8,000-pound, upright cylindrical compressor with a remarkably high center of gravity. To prevent cargo shifting, regulations require the securement system to withstand a minimum 0.8 g forward deceleration force and 0.5 g lateral acceleration forces. Which combination of blocking and bracing correctly applies FMCSA securement principles without compromising the structural integrity of the trailer?

  1. Fastening timber directly to the trailer deck immediately ahead of the load base to provide blocking against sliding, and installing diagonal timber struts anchored to the trailer's vertical wall posts extending to the upper section of the compressor to provide bracing against tipping.Cevap
  2. B
    Fastening heavy-duty timber blocking tightly against the base on all four sides to counteract both sliding and tipping, while keeping the upper portion of the load completely unrestrained.
  3. C
    Installing diagonal bracing struts from the upper section of the equipment directly into the interior plywood side panels to prevent lateral movement, while relying on deck friction to fulfill the forward securement requirements.
  4. D
    Placing unattached dimensional lumber around the base of the compressor and relying on a single transverse tie-down strap routed over the top to press the lumber firmly into the deck.

Cevap

The correct approach involves fastening floor-level timber to the deck to block forward sliding, combined with diagonal struts anchored to the structural vertical wall posts to brace against tipping.
The correct answer accurately separates the roles of blocking and bracing while accounting for the trailer's structural limits. Fastening timber to the deck addresses the 0.8 g forward deceleration force at the base, effectively preventing sliding. Because the load has a high center of gravity, it is highly susceptible to tipping from lateral (0.5 g) and forward forces. The diagonal struts attached to the trailer's structural vertical wall posts provide the necessary leverage against the upper section of the equipment to counteract tipping, without risking a failure of the weaker interior plywood liners.

Adım Adım Çözüm

1
Analyze the load characteristics and the mandated performance criteria.
The load is 8,000 lbs with a high center of gravity, requiring protection against 0.8 g forward (sliding/tipping) and 0.5 g lateral (tipping) forces.
Identifying the specific forces and the physical vulnerability of the load dictates whether blocking, bracing, or both are necessary.
2
Determine the proper application of blocking.
Blocking must be securely fastened to the deck at the base of the compressor to prevent the 0.8 g forward sliding motion.
Blocking works by transferring the longitudinal sliding force directly into the structure of the floor.
3
Determine the proper application of bracing for a high center of gravity.
Bracing must extend from the upper section of the compressor to the trailer's vertical wall posts.
Upper bracing prevents tipping. It must anchor to the trailer's structural members (the posts) because standard dry van plywood liners will fail under a 4,000 lb (0.5 g) lateral force.

Anahtar Kavram

Mechanics and structural limits of combined blocking and bracing systems
Bu soruyu puanla

Konular

Cargo Securement: Blocking and Bracing

Bu konudan daha fazla soru