Hydraulic Flow Control Structure

[eli_morgan]

A little out of my element as an electromechanical but my team has put me up to the task. Which has left me stumped.

I have a highly fluctuating amount of water coming into two streams that then go into a set of box culverts under my streets. However, the condition of the culverts is unknown at this point. When high flows and the 100 year storm arrive, we get drastically overwhelmed by the amount of flows seen from the brook. The brook is approximately 20-30 feet wide, 18 inches deep, diverging into two streams that are 12-15 feet wide and 20 inches deep. Currently, previous management placed 12 inch DI CL 52 cemented bollards in the brook to try to reduce flow (I admit I am a young engineer, but this was not the best design). I am proposing putting a pre-cast structure in the bank that will have a center portion that can be lifted from above to restrict or open flow (photos coming). However, I ran deflection and deformation calculations and I have no idea where to begin for material selection. Mild steel failed in shear, some of the other steels make this out of my budget $20,000. I am also not sure that I am using the right calculations for designing this.

The goal is to make this safe where the staff in the City can enter the confined spaces of the box culverts for asset management and cleaning.

I will add photos of the proposed structure without the center control in it. I ran the model in Solidworks's analysis tool and it can handle the stresses.

This is my first post on this forum, if this needs to be in another section of this forum, let me know.

Thoughts?

[eli_morgan]

Here is my initial design, with my chicken scratch for math.