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U.S. Department of Energy
Office of Scientific and Technical Information

Achieving uniform-high-tensions in mechanical-anchor bolts. Open file report, 15 January 1980-15 November 1981

Technical Report ·
OSTI ID:5065080
Towards the goal of achieving uniform high tensions in roofbolts to provide superior roof support for extended periods, mechanical anchor bolts were installed in a mine in eight different ways--under torque thrust control with and without hardened washers, belleville washers, and tension equalization; in a conventional manner with and without a hardened washer. The various bolt groups were analyzed in terms of tension uniformity and mean tension levels. Installing the bolts accurately with a hardened washer under the bolthead, and proper torque thrust control resulted in the most uniformly tensioned bolt--with a coefficient variation of only 14%, an improvement of three times over a conventional installation. Also, these bolts maintained a high tension level--80% of the installation tension compared with 50% achieved conventionally.
Research Organization:
Terra Tek, Inc., Salt Lake City, UT (USA)
OSTI ID:
5065080
Report Number(s):
PB-84-143718
Country of Publication:
United States
Language:
English