Concrete beam beneath existing masonry wall

[MIStructE_IRE]

An architect is looking to remove the back wall of a house (6.8m span). Normally I do this in steel and limit dead + live deflections to L/360 to prevent excessive cracking in the masonry wall.

In this case the architect is looking to use an in situ concrete beam and the brick wall is 400mm thick!! Normally when designing a concrete beam I would use the L/d deem to satisfy rules for deflection. This however comes nowhere near dead+live deflection < L/360 when checked on FE software - so the RC beam I’d need becomes ridiculously deep!

If designing this for a new build for example I’d never dream of working out concrete beam deflections in mm… so am I going OTT attempting to get it to fit in here?

 

[GC_Hopi]

Steel beam encased in concrete might get you the best of both worlds.

 

[MIStructE_IRE]

I think you might be on to something there!

Good idea

 

[XR250]

I would use a lot more than L/360 for existing masonry unless you just want it to crack.