Extending Traditional Limits in Shaft Steelwork Design

摘要

Current structural design of shaft steelwork uses procedures developed twenty years ago, and subsequently applied to numerous shafts now operating in various countries. However, specific project constraints and the drive for continuous improvement suggest further increases in bunton spacing. The design procedures make provision for designing shaft steelwork using greater bunton spacing than the 6,0 m distance commonly used now. The possibilities for extending the boundaries are theoretically assessed, and the practical implications are discussed. Time constraints for equipping a mine shaft in South Africa recently led to shaft steelwork design using 8,0 m bunton spacing, which has been successfully implemented. An earlier proposal to use 9,0 m bunton spacing was proven theoretically, but was rejected for various practical reasons. Bunton spacing of 8,0 m or 9,0 m is shown as the practical limit in many cases using current guide size norms. Larger guides will allow greater bunton spacing, but they have implications on total mass of steelwork, shaft layout and clearances.