reinforcement design in square in-situ manhole

[tsli001]

Hi guys :

I think I may posted the same type of question for manhole design before. However, I have not yet got my answer. So, I had decided to ask the question in a different way. Currenty, I am working in southeast asian with american drainage design experience. Believe or not, all the drainage manhole is in-situ square manhole.So, it will require me to design the manhole wall reforcement.

Now, I have never did a RC design in ages, not to mention to design manhole reforcement. So, is there anyone can help me out walk me through it? A sample will be great.

thanks

 

[gbam]

tsli001 - Sorry, but I always pass the structural design for these type of structures to a structural engineer. Don't you have access to a structural Eng in your office?

 

[kieran1]

Simple way would be to design the manhole walls as a concrete slab spanning between perpendicular walls. Design slab for lateral earth loads and stiffen the corners with bars on each face.


Kieran

 

[csd72]

Treat it as a slab supported on three sides and with a triangular surcharge load.

I think there are tables in roarks but there are tables in many of the good concrete design handbooks.

Alternatively you could design it by yield line analysis and probably get similar results.

Just remember to be careful detailing the corners to avoid any bowstring effect.

 

[tsli001]

Appearly over here we also need to calculate the walk by ourself. So, I need to do it. Is there any excel sheet out for RC designb. Other thing is can someone explain a bit on the 'bowsting effect' for the corner. Me and my co-worker really having trouble to follow it.

Thank you