Brick Manhole Design

[BridgeEI]

I am looking for some references regarding the design of manholes that are constructed of brick and mortar. I have a reviewer who is asking for documentation that an opening which has been plugged with brick and mortar is capable of handling the lateral force from the earth pressure.

I’ve tried some simple calculations and I can’t get it to check, but this is common practice when you build a storm sewer.

There are city/DOT standards which construct brick manholes over 12feet deep and they don’t have any issue. I’m trying to find a simple means to prove to the reviewer that this isn’t an issue.

 

[r13]

Is it circular or rectangular? Length and width if latter.

 

[BridgeEI]

Rectangular. It would be simpler if it was circular since hoop stress is what you would be looking at.

 

[WARose]

I don't get why anyone would want proof in that situation. If you can reference a city/DOT standard....what else is there to prove?

In any case, be careful because a lot of older manholes were done with 4" brick (i.e. like house brick). But in the typical standard you see for manholes these days.....yes you can have unreinforced "brick".....but we are talking 8" min.

To make it work, you'd probably have to do the type of analysis you see in ACPA's Concrete Pipe Design Manual.

 

[r13]

Here is a paper for your use (need to download after linking). It's talking about circular manhole, but the reference (2) may be the source to look into. Link

 

[BridgeEI]

Thank you for the paper. I’ll take a look through it. I’m pretty much taking the stance that WARose stayed and just cram standards down their throats. It’s frustrating when you receive comments like this from reviewers who won’t use any common sense...

 

[r13]

BridgeEI,

Make sure the city meant it ok with "rectangular" brick manhole constructed 12' deep, because the paper gave me an impression the 12' was for circular manhole.

 

[robyengIT]

see also : ACPA Design Data 41

 

[r13]

If the reviewer is came from the municipality, obviously he knows something that you don't. Note that some locals have discontinued the use of brick manhole for cases call for replacement rather than rehabilitation.