Description and Analysis of Crib Wall Failures

Crib walls are a form of gravity retaining walls that are constructed of prefabricated interlocking concrete units. The space between the interlocking units or crib is filled with soil to provide weight and stability before the adjacent backfill is placed. In recent years, crib walls have been used in greater numbers and heights to solve varied retaining problems. This has resulted in an increasing number of failures. This paper discusses common problems with the design and construction of crib walls by summarizing five crib wall failures ranging in height from 20 to 40 feet that occurred recently in Southern California. The laboratory test procedures and test results performed during the forensic analyses of these failures is presented. Single and multiple assemblies of drycast crib elements were tested to destruction under laboratory conditions. Proper and improper construction procedures are also discussed and a crib wall design specification section is presented for inclusion in model building codes.