And if the metal parts bite into the wood, this helps to keep sliding from happening. These factors are especially true in field repairs, because most ground is not perfectly level and hard, like a concrete garage floor would be. Even on concrete, cribbing is often preferred.
When metal parts penetrate the wood, it prevents sliding. These conditions are particularly true during field repairs where ground is not uniformly flat and hard, similar to a concrete garage floor. Even on concrete, using cribbing is often preferred.