... Standard: YB/T4001, ANSI/NAAMM-MBG531, BS4592, AS1657, JS31011.3 Grating Dimension Load Bearing Flat Bar sizeThickness≥3mm, depth ≥19mm19X3 ... 1.4 Grating type: Bearing bar: Plain type, Plain I type, Serratd type, Serrated I type; Cross bar: Square twisted cross bar, Round cross bar2. ... , so no need pre-embedded supporting part. 2.3 Security type of Drainage/Ditch Cover Both ends connected with steel ...