We had an out of hours incident on Wallace St where a vehicle with low ground clearance struck a bolt on the high part of the road plate and sustained some damage. The road plate was over a water cut in position and had been installed in accordance with the WWL road plate policy:
- Gritted roadplate
- Asphalt Ramps
- Bolted Down
- Carpet under the bearing
Roadplates are necessary in situations where the excavation cannot be backfilled. GPFL attended site and installed positive traffic management to control vehicle wheel paths and ensure that there was no further risk of low vehicles striking the plate. A monitoring regime was set up for the remainder of the weekend until the plate was removed on the Monday morning.
Communication took place with the owner and the vehicle was repaired. An investigation took place and the significant camber of the road was identified as one of the main contributing factors.
The camber meant that the side of the plate in the middle of the lane was high in comparison with the surface of the road. Asphalt ramps were in place but if a vehicle traversed the arrangement with one wheel just off the ramp and the other on the plate then the clearance on the high side of the plate would be reduced.
The key learning is that on roads with significant camber additional controls are required:
- Consider low vehicles and groundclearance for all parts of the plate.
- Consider leaving positive TM in place to control vehicle paths over the plate.
- If there is low ground clearance, then extend the asphalt ramps to raise both wheels as they pass over the plate.
Do follow the WWL policy
Do consider ground clearance of all vehicles
Do consider leaving TM in place
Do ensure that ramps are long enough to even out the carriageway.