... advantages such as light weight,high strength,great load-bearing capacity,being economical of materials,ventilation and light ... in various ships; floorings in various bridges such as railway bridge sidewalks,over-the-buildings and roads; drainage trench covers ... GB/T7001988Hot Galvanizing StandardCHINA GB/T139122002Symbol of Steel Grating1. Bearing bar pitches may be 12.5 152030406080and 90mm,of ...