Vertical Load Capacities of Roof Truss Cross Members

Details

• Personal Author:
  Gearhart, David F. ; Mohamed KM
• Description:
  Trusses used for roof support in coal mines are constructed of two grouted bolts installed at opposing forty-five degree angles into the roof and a cross member that ties the angled bolts together. The load on the cross member is vertical, which is transverse to the longitudinal axis, and therefore the cross member is loaded in the weakest direction. Laboratory tests were conducted to determine the vertical load capacity and deflection of three different types of cross members. Single-point load tests, with the load applied in the center of the specimen and double-point load tests, with a span of 2.4. m, were conducted. For the single-point load configuration, the yield of the 25. mm solid bar cross member was nominally 98. kN of vertical load, achieved at 42. cm of deflection. For cable cross members, yield was not achieved even after 45. cm of deflection. Peak vertical loads were about 89. kN for 17. mm cables and 67. kN for the 15. mm cables. For the double-point load configurations, the 25. mm solid bar cross members yielded at 150. kN of vertical load and 25. cm of deflection. At 25. cm of deflection individual cable strands started breaking at 133 and 111. kN of vertical load for the 17 and 15. mm cable cross members respectively. [Description provided by NIOSH]
• Subjects:
  Mining Occupational Health Particulate Matter Safety
• Keywords:
  Analytical-models Author Keywords: Roof Truss Cables Coal-mining Coal Mining Construction Construction Materials Environmental-control-equipment Environmental-engineering Environmental-technology Equipment-reliability Geology Ground Control Laboratory-testing Load Capacity Mining-industry Overloading Performance-capability Roof Support Roof Supports Roof Support Systems Simulation-methods Statistical-analysis Stress Structural-analysis Tensile-strength Testing-equipment Underground-mining

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• Series:
  Mining Publications
• ISSN:
  2095-2686
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PMRD - Pittsburgh Mining Research Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  26
• Issue:
  3
• NIOSHTIC Number:
  nn:20047830
• Citation:
  Int J Min Sci Technol 2016 May; 26(3):517-520
• Contact Point Address:
  David F. Gearhart, Office of Mine Safety & Health Research, National Institute for Occupational Safety & Health, Pittsburgh, PA 15236
• Email:
  dgearhart@cdc.gov
• Federal Fiscal Year:
  2016
• NORA Priority Area:
  Mining
• Peer Reviewed:
  True
• Source Full Name:
  International Journal of Mining Science and Technology
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:49b7b5543d4d1d8fe3e1b5fe0cd29f969614de7dd4b4000a43d653763a38dc22a056672e98aeb8947d697ce77f8599ca397da7c28aded8b1723d8923e24eea10
• Download URL:
  https://stacks.cdc.gov/view/cdc/228241/cdc_228241_DS1.pdf
• File Type:
  [PDF - 1.54 MB ]