The objective of this program was to evaluate a number of roof support systems that have some physical similarity to the truss introduced by the Birmingham Bolt Company in 1966. The report is in two parts: part I is a state-of-the-art study of roof truss technology as of January 1979. Included are a history of the truss concept, a review of analysis techniques, a record of hardware available and equipment used in its installation, and examples of user experience. Part II is concerned with a study of the role of friction in the behavior of a roof truss.
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