Tetrapods as a Scour Countermeasure

Few materials have been studied for their effectiveness in protecting bridge piers and abutments from local scour other than riprap. Recent research conducted at the FHWA research facility in McLean, Virginia, focused on the feasibility of using tetrapods as a scour countermeasure. The geometry of the tetrapod is believed to enhance its ability to resist movement and in turn increase its scour protection characteristics. The interlocking capability of the tetrapod is thought to account for higher stability when compared to riprap. The results of these experiments show that when compared to an equivalent size D 50 of riprap, tetrapods may exhibit a higher degree of stability.