Product Catalog
Steel Rib Supports
Steel ribs are efficient and safe ground control elements in underground construction. Selection of section type and dimension is accomplished following structural and project requirements. Besides custom-bent steel ribs, straight beams, forepoling sheets, and steel lagging can also be fabricated. Jennmar Civil manufactures cold-formed beams for underground support applying sound techniques for shaping steel required in the tunneling industry.
Techniques learned about shaping steel for strength, performance, and value in the world’s tunnels and shafts can be applied to the benefit of each project.
• Width: flange width plus 1"
• Thickness: 4" and 5" sections — 3/8"
–– 6" sections — 1/2"
–– 8" sections — 5/8"
–– 10" sections — 3/4"
–– 12" sections — 1"
• Bolt size (A325) and quantity:
–– 4" sections: (2) 3/4" dia
–– 5" and 6" sections: (2) 1" dia
–– 8" and 10" sections: (4) 1" dia
–– 12" sections: (6) 1" dia
The above are for normal loading conditions. For extreme conditions, a full-moment strength joint may be required.
• 5" sections: 5/8" x 9" x 9"
• 6" sections: 5/8" x 9" x 9"
• 8" sections: 3/4" x 12" x 12"
• 10" sections: 1" x 14" x 14"
• 12" sections: 1-1/4" x 16" x 16"
• Length = rib spacing + 6"
• With 4" and 6" sections: 3/4" dia.
• With 8" and 10" sections: 3/4" dia.
• With 12" and above: structural spreaders are recommended
• Length = rib spacing — web thickness
• With 3/4" dia. tie rods: 2" dia.
Techniques learned about shaping steel for strength, performance, and value in the world’s tunnels and shafts can be applied to the benefit of each project.
Accessories Used with Ribs
Butt Joint
• Butt plate height: rib depth plus 1"• Width: flange width plus 1"
• Thickness: 4" and 5" sections — 3/8"
–– 6" sections — 1/2"
–– 8" sections — 5/8"
–– 10" sections — 3/4"
–– 12" sections — 1"
• Bolt size (A325) and quantity:
–– 4" sections: (2) 3/4" dia
–– 5" and 6" sections: (2) 1" dia
–– 8" and 10" sections: (4) 1" dia
–– 12" sections: (6) 1" dia
The above are for normal loading conditions. For extreme conditions, a full-moment strength joint may be required.
Foot Plate
• 4" sections: 1/2" x 7" x 7"• 5" sections: 5/8" x 9" x 9"
• 6" sections: 5/8" x 9" x 9"
• 8" sections: 3/4" x 12" x 12"
• 10" sections: 1" x 14" x 14"
• 12" sections: 1-1/4" x 16" x 16"
Tie Rods
• A529 rod stock with 4" N.C. thread each end• Length = rib spacing + 6"
• With 4" and 6" sections: 3/4" dia.
• With 8" and 10" sections: 3/4" dia.
• With 12" and above: structural spreaders are recommended
Pipe Spacers
• Schedule 40 pipe stock• Length = rib spacing — web thickness
• With 3/4" dia. tie rods: 2" dia.