... strength, (2)light structure, (3)good appearance (4)durable in use HDG steel grid/steel grating for ditch1.Comprehensive type and ... broadest range in dimension.1.1 Material Q235 , or other ... 25X4.7, 25X5…..40X6, 40X8, 40X10,….90X6….Pitch of Load bearding flat bars(mm)12.5,15, 20, ... , 34.8, 35.3, 40, 60, 80……Pitch of cross bars(mm)38.1, 50, 50.8, 70, ...