Irregular building L-Shaped

[gotlboys]

I am designing an L-shaped four-storey apartment with dimension 25x56m. Column grid is 5m on both directions. I am aware that it would be irregular bldg and some engineers may like to go for dynamic analysis which I am not really familiar with.
What would your suggestions be to account for the irregularity and avoid dynamic analysis? I have a reference which recommends shear wall and separation of building. If these two recommendations work for such irregularity, then how would I analyze seismic load distribution (static analysis) on the frame. A simple direction may lead me to a great solution.

 

[JAE]

To avoid the complexities, break the building into two separate structures with an expansion joint at the juncture between the two wings....you would have two rectangular, regular buildings.


Check out Eng-Tips Forum's Policies here:
faq731-376

 

[Guastavino]

Check out Terry Malones book on analysis of irregular structures. It goes through the use of transfer diaphragms, offset chords, etc. it's a great reference to point you in the right direction for these types of buildings.

Also, as JAE said, expansion joints can work. I'm not a big fan of them when I can avoid them though. They are expensive and require a lot of detailing. But they certainly do the job.

Good luck

 

[gotlboys]

Thanks a lot for your sharing and information JAE and njlutzwe.
As recommended to look for the book of Terry Malones, I have searched for it to get one but it seems the page doesn't provide any option to buy a fdp format of the book. I am living in Timor-Leste, one of South East Asian countries. I finished my study in the Philippines and have returned a year ago. There is no such book available here.
If you have any pdf format of it, I would love to purchase a pdf format one.

 

[KootK]

You can purchase a Kindle edition from Amazon which can be viewed on your computer, phone, iPad, or Kindle. That's what I have.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[gotlboys]

After two days of searching for it, I finally got it. The books explains very well the analysis of irregular structures but it seems like this book is for wooden structures. The building I am designing is of reinforced concrete structure. Do you think the analysis and methods presented in book of Terry Malones are appropriate to use as tool in analyzing the situation in question?

 

[KootK]

For the most part, no. Although some of the concepts are the same. Have you decided to separate the building wings as JAE recommended? Which aspects of the design are you needing advice on?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[gotlboys]

I haven't decided to separate the building as recommended because it is expensive as you said and so do some colleagues here. I asked my teacher who is in the Philippines, he advised to adopt shear wall on x- and y- axes along the outer perimeter to take account of the seismic forces instead of separating them into two which may not be inconsistent with the architectural demand. That's the usual problem.
So, I would like hear from you on which solution to adopt and a brief experience sharing or reference to help me go about the analysis and design.
Thanks so much for that big help from a distant.

 

[ahmedhegazi]

gotlboys,

what is the seismic zone /classification for your building , which design code you use...

 

[oldrunner]

L-shaped buildings have big torsion problems that have to be dealt with. In the past, we have tried to avoid them. Two separate buildings with good detailing between them may be a safer option. Certainly would want to carefully check the possible movement between the two for any banging or offset action. You might be able to obtain some guidance from the Structural Engineers Blue Book which you can access here:

http://www.seaoc.org/bluebook/index.html

 

[haynewp]

Differential temperature movement between the adjoining wings would also be taken care of with the expansion joint. Older L and T shaped buildings and ones I have designed used this, the older ones were back before all the special seismic stuff.