DAMBRK Questions

I recently received the Dambrk program and some students are working to analyse the example problems. There are some little problems with the cross sections having a bridge because we didn't understand well the meaning of some inputs. In particular I'd like to have some explanations about the meaning of bridge opening.

a) Does it describe the area of the channel where there is the flow? If it's exact:why in the example P01.DBK the bridge opening doesn't coincide with the channel ?

b) why the bridge opening and the channel can be above the roadway ?

In some places in southern USA, it is possible to have roadway overflows (much like weirs) to allow the discharge of overflow rather than topping the bridge deck and damaging it. That is what is meant by lower and upper elevations.

Thanks for your help.
Best wishes.
Marco Masetti

>a) Does it describe the area of the channel where there is the flow? If it's
exact:why in the example P01.DBK the bridge opening doesn't coincide with
the channel ?

The bridge opening is defined as elevation and top width. It is meant to describe the bridge opening area. In example P01.DBK, the actual bridge opening is different than that of the cross-section.

>b) why the bridge opening and the channel can be above the roadway ?

In some places in southern USA, it is possible to have roadway overflows (much like weirs) to allow the discharge of overflow rather than topping the bridge deck and damaging it. That is what is meant by lower and upper elevations.

Sincerly,

Chris E. Maeder
chrism@bossintl.com