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Driver's Handbook on Cargo Securement - Chapter 13: Large Boulders

[Picture of truck hauling four large boulders]

What Does This Section Cover? (Section 3.11.1)

The requirements in this section apply to any piece of natural, irregularly shaped rock that:

Weighs more than 5,000 kg (11,000 lb.) or has a volume greater than two cubic meters
Is transported on an open vehicle or in a vehicle whose sides are not designed and rated for the transportation of boulders.

[Diagram of a cube where each side is 1.25 meters (4 feet)]

Two cubic meters (yards) is about the size of a box with dimensions of 1.25 (4 ft) on every side

Boulders weighing less than 5,000 kg (11,000 lb.) may be secured in one of two ways:

Using the requirements for large boulders (this section)
In some situations, using the general cargo securement 
requirements (Section 2) if: 

Transported in a vehicle designed to carry boulders.
Boulders are stabilized and adequately secured by tiedowns.

Rock that is formed or cut to shape and has a stable base can be secured:

Either by the requirements for large boulders.
Or by the requirements for general cargo (Section 2).

Positioning Boulders (Section 3.11.2)

Requirements

Place each boulder on the vehicle with its flattest and/or largest side down.

[Diagram of truck with a large boulder cargo. The large bolder is setup so it's flattest side is is down]

Flattest and/or largest side down

Support each boulder on at least two pieces of hardwood blocking (at least 10 cm x 10 cm (4 x 4 in) that extend the full width of the boulder.

Place hardwood blocking pieces as symmetrically as possible under the boulder so they support at least 3/4 of the length of the boulder.

[Diagram of truck with large boulder cargo. The boulder has a hardwood blocking piece below it.]

Hardwood blocking pieces placed under the boulder

Positioning Boulders (Section 3.11.2) (continued)

Requirements

If the flattest side of the boulder is rounded or partially rounded, place the boulder in a crib made of hardwood fixed to deck of vehicle.

Boulder should rest on both deck and timber, with at least 3 well-separated points of contact that prevent rolling in any direction.

[Diagram of truck with large boulder cargo. The boulder is placed in a hardwood crip.]

Boulder placed in a hardwood crib

If a boulder is tapered, point the narrowest end towards the front of the vehicle.

[Diagram of truck with large boulder cargo. The narrow point of the boulder is facing the cab of the truck.]

Narrowest end placed toward the front of the vehicle

Tiedown Requirements (Section 3.11.3)

Requirements

Use only chain to secure large boulders.

[Picture of large boulder chained down to the truck bed]

Chain is used to secure large boulders

Tiedowns in direct contact with the boulder:

Should be located in valleys or notches across the top of the boulder
Must be arranged to prevent sliding across the rock surface.

[Diagram of large boulder chained down to the truck bed. The chain goes through notches in the boulder.]

Tiedown is located in notch

Special Circumstances: Securing a Cubic-Shaped Boulder (Section 3.11.3.1)

The securement of a cubic-shaped boulder must meet these requirements in addition to the other large boulder requirements in Section 13.

Secure each boulder individually with at least two chain tiedowns placed side-to-side across the vehicle.
Place tiedowns as closely as possible to the hardwood blocking used to support the boulder.

[Diagram of truck with cubic shaped boulder cargo. The cargo is loaded in the middle of the truck and tied down in two locations. Acceptable securement of a cubic shaped boulder]

[Note:] The aggregate WLL of the tiedowns must be at least 50% the weight of the boulder.

Special Circumstances: Securing a Non-Cubic Shaped Boulder with a Stable Base (Section 3.11.3.2)

The securement of a non-cubic shaped boulder with a stable base must meet these requirements in addition to the other large boulder requirements in Section 13.

Secure each boulder individually with at least two chain tiedowns forming an "X" pattern over the boulder.
Pass the tiedowns over the center of the boulder and attach them to each other at the intersection by a shackle or other connecting device.

[Diagram of truck with non-cubic shaped boulder cargo. The cargo is loaded in the middle of the truck and tied down in two locations. The two ties do cross at the top of the boulder. Acceptable securement of a non-cubic shaped boulder with a stable base]

[Note:] The aggregate WLL of the tiedowns must be at least 50% the weight of the boulder.

Special Circumstances: Securing a Non-Cubic Shaped Boulder with an Unstable Base (3.11.3.3)

The securement of a non-cubic shaped boulder with an unstable base must meet these requirements in addition to the other large boulder requirements in Section 13.

Surround the top of each boulder at a point between 1/2 and 2/3 of its height with one chain.

[Note:] The WLL of the chain must be at least 50% of the weight of the boulder.

Attach four chains to the surrounding chain and the vehicle to form a blocking mechanism that prevents any horizontal movement.

[Note:] Each chain must have a WLL of at least 25% the weight of the boulder.

[Note:] The angle of the chain must be less than 45 from the horizontal.

[Diagram of truck with two non-cubic shaped boulders with unstable bases cargo. Each boulder is loaded on two spacer bars to level it out. Then there are two tiedowns on each bolder that are at 60 degree angles. Finally there is a circular tie towards the top of each boulder that connects the two tiedowns on each boulder.]

Acceptable securement of a non-cubic Shaped boulder with an unstable base

Updated: Friday, March 14, 2014