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Distribution Electric Network Manhole Lid Reinforcement

After an incident with a manhole explosion that projected lids into the air, we were asked to support the electric network system in Florida. Our job? Design a reinforced, more resilient manhole lid that would be affixed to the reinforced manhole.

We calculated what type of reinforcement would work for this project, assessing the vertical stresses from traffic loads and impact loads within the manhole. These calculations informed our solution¡ªa self-venting manhole lid using anchor bolts tied to the top slab of the manhole.

The benefit of this approach is that it can be utilized for different field conditions¡ªsuch as elevation changes¡ªand the retrofit kit will self-vent. Another key to the success of this design is ease of replication. The program includes replacing over 800 existing sites as well as adopt the cover design in future projects. This type of design is becoming very popular and has been adopted by utility companies across North America to better mitigate safety risks.