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Achieving Uniform-high-tensions in Mechanical-anchor Bolts.
Available for Reference At Bureau Libraries :122 pages
Toward 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; and in a conventional manner with and without hardened washers. The various bolt groups were analyzed in terms of tension uniformity and mean tension levels. Installing the bolts accurately with hardened washers under the bolthead, and with proper torque control, resulted in the most uniformly tensioned bolts--a coefficient variation of only 14%, an improvement three times over conventional installations. Also, these bolts maintained a high tension level--80% of the installation tension compared with 50% achieved conventionally.
CP; Final Contract Report;
NTIS Accession No.
Available for Reference At Bureau Libraries
Terra Tek, Inc.
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division