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Civil Engineering/IBC 2009 1809.13 Confusion


Hello Sir,
I am designing a concrete frame in seismic zone 4 to which I have assigned seismic design category E. I ave insufficient data for site soil so I have assumed soil type Sd. Now I m to ask that IBC 2009 1809.13 says,footings must be interconnected. Whether this requirement only for Site Classification as E,F or it is for all site classifications? Moreover this requirement means tie beams must be at footing level or Tie beams provided at plinth level also satisfies this provision?
Thanks and regards,

Dear Waqas

The tie beams must be introduced in foundation level. They guaranty the footing of lateral resisiting frames be safe under slip action. They transfer the seismic horizonatal reaction to neighbour footings. Acually one can calculate the slip resisting force and design an appropriate footing with probably some piles to have a safe foundation . Actually with these provision you dont need such a sophisticated calculations. Then I assume that you need to fulfill this article of the code everywhere instead of so complicated calculations.


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Babak Esmailzadeh Hakimi


I can answer questions in Structural Engineering, Earthquake Engineering, Project Management and Project Control topics!


I am experienced in the area of earthquake engineering in electrical power industry, i.e. Lifeline Earthquake Engineering. My focus has been on structural seismic design of power installations. Recently I have got involved in project management in the category of constructional engineering.

Sinam Consulting Engineers Co.

Bs degree in Civil Engineering from Ferdowsi University ,1988, Mashhad Iran, Ms degree in Earthquake Engineering, Sharif University of Technology, 1993, Tehran, Iran

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