... , railway, industrial engineering and so on.Type of bearing bar:W--welded steel grating L-- pressure-locked C-- socket- ... weldingBearing bar centers:15-30, 40, 60, 80, 90 mm etc ... . with 30, 40 mm recommended.Cross bar centers:any greater than 30mm is ok. with 50, 100mm ... :5. Installation type: galvanized U type steel I bar grid ditch cover