ABSTRACT
This paper starts with a brief chronicle of truss development. It traces the basic principles and theory behind truss development and application. Two case studies are discussed. In Case I, roof trusses were successfully used to drive 2000 ft. (600 m) headings, while in Case II the effectiveness of truss has been evaluated by in mine measurements and by physical and analytical study. The physical model is limited to a 10 in. (25 cm) thickness of immediate roof and a horizontal and 45 degree angle to horizontal inclined chord anchorage, while the analytical study consists of 15 finite element models in which the thickness of the immediate roof and the angle of the inclined chord varies from 10 in. to 24 in. (25–60 cm) and horizontal to 60 degrees from horizontal, respectively. Overall the study indicates that the truss provides a significant reinforcement to the immediate strata surrounding an opening.
