Products, high strength, and aging, corrosion and high temperature fire, do not creep, no return, ... the construction site of the base beam by bolts fixed in the latter part of cable trench walls, support ... 500mm, 470mm length of the support beam and fixed beam thickness of 30mm, fixed-screw bolt straight bit 16 mm.3. ... , communications engineering, chemical cable trenches, subway tunnels and other fields