Drainage Solutions

Grate Loading – Dynamic

Dynamic Loading

Typical loading standards for trench drains only address the static load or vertical load put on a grate.  However, the linear nature of trench drains subject them to forces and loads that point inlets and catch basins are just not subjected to. It is these dynamic loads that typically destroy the integrity of a trench drain. 

When considering a Trench Drains for any application, it should also be treated as an assembly (grates, frames, trench conduit). The weakest member in any system is your maximum design load. 

Examples of Dynamic Loads

  • Turning Forces
  • Braking Forces
  • Cyclic Loading (high speed repetitive traffic)
  • Snow Plows



Load Class
Load Class
Load Class


No Dynamic Load Low Speed Dynamic High Speed Cyclic and/or High Speed Dynamic

Anchor Frame

Not Required Independent Anchor Frame Independent Anchor Frame

Preferred Grate Material


Ductile Iron ASTM A-536 65-45-12 or 80-55-06

Ductile Iron ASTM A-536 65-45-12 or 80-55-06

Grate Anchor Mechanism

Bolted or Toggle Bolted, Toggle, or Boltless Boltless or Bolted (if picture framed)

Modulus Sandwich

Allowed Not Allowed Not Allowed

Typical Applications

Walkways, Pedestrian Local Roadways, Maintenance Garages Ports, Airports, Highways