(1)high strength, (2)light structure, (3)good appearance (4) ... for ditch1.Comprehensive type and broadest range in dimension.1.1 Material Q235 , or other equivalent material1.2 Grating Conformity Standard: YB/T4001, ... .3, 40, 60, 80……Pitch of cross bars(mm)38.1, 50, 50.8, 70, 75, 80, 100, 101.6, ... 102……The sizes and dimension is not limited to above.1.4 Grating type: flat bar: plain type, plain I ...