Combined Footing Design Problem 2

[Faisal0088]

Hi,
Few days back I have designed a 7 storied RCC building combined foundation. In my design I did consider soil BC 4Ksf. C1 and C2 each P= 278 Kip. The size was 19.5'x7.5'.

My problem is, during construction the client did not follow my design. They reduced the size of the footing. Its now 17'x5' !!! . I have re analyzed the soil pressure it seems 6Ksf above!!!. I have told them to demolish that. Still they are asking me to let them to connect MS Bar and Extend the edge as per my early design.
Whats the solution for such case. Will it be appropriate to connect MS Bar and cast RCC along the edge? Will it work as like a homogeneous foundation?

Please some one help me! Looking forward to hear from my Engr fellows around the world.

Thanks

 

[hokie66]

Stick to your guns! Have them pull it out. There is no way you can economically repair this footing. It might be a different story if this were an existing building, but it is simple to pull out a footing when nothing has been built on it.

 

[Ron]

Agree with hokie66. No point in compromising the design. Besides, if you do the doweling correctly, it will likely be as expensive as taking out the foundation.

What they are proposing can be done, but the results can be risky for shear transfer and it depends on how your foundation is being loaded. If heavily loaded near the outside, you'll have problems.

Be prepared that "they" will bring another engineer in who will say it is not a problem to do as they propose....as hokie66 noted...stick to your guns. It is your design.

 

[rowingengineer]

agree with hokie if suspended slabs are not poured. if the slabs are already poured, I would start with a geotechnical assessment of bearing capacity for the footings in question.

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[msquared48]

Ask the contractor if he can read plans. If he answers yes, then have him remove it. If he answers no, fire him.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com