RC Junction Pipe Box

[LicensedToPEe]

am working on a design of a 7'x7'6' reinforced concrete junction box that has a 18 ft precast manhole sitting on the top of it, has a 48" dia. opening on one wall, and 30" dia. opening on 2 other walls (with one wall solid). I have a good idea on the loading (dead and lateral earth pressure) however I need guidence on reinforcement calculation. I know some rebars are inclened at 45 deg. around the pipe holes. I tried using STAAD to model it as a 3-D box with circular openings, however, the reinforcement comes out in perpendicular direction only. Besides using STAAD, are there any other methods I could use? Any help is appreciated.

 

[tincan]

The bars positioned at 45^ about the MH opening are distribution bars. The bars spanning the box are the load carring members.
Best, Tincan

 

[LicensedToPEe]

Tincan,

is there a known guideline as to how the distribution bars are sized and spaced? If I assume that the reinforcement bars that would be placed in the area of the hole (had the box been constructed using solid walls) are to be the ones spaced out at a 45 deg. angle around the opening, would that be a wrong assumption?

 

[tincan]

We normally space the distribution steel at 6-12" centers depending upon the room avaible. 2-3 bars is sufficient for the smaller openings. We usually use the same bar diameter as the moment reinforcement.
Best, Tincan.

 

[youssef91]

I'm trying to find any material stresses information for brick walls for a house built in 1920.
The owner wants to change an existing flat roof to an open roof deck,plan checker asked for a complete design for the brick wall supporting this existing deck as the life load has been changed.
Also, is there any information for drill and epoxy for this type of old brick walls?
Any help is appreciated

 

[youssef91]

I am sorry, I posted to a wrong location.