Replacing moment frame by outrigger/belt truss 1

[ahmedhegazi]

According to ASCE07-05 table 12.2-1 , Special reinforced shear wall is not allowed to be used for SDC (E)for buildings exceeding 160 ft in height.
This put requirements for adding moment frame to Special reinforced shear wall(Dual system) for resisting seismic force.

My question is ,can the moment frame replaced by any of the following

1- outriggers truss in both directions provided at 1 floor connecting premeter columns to RC core wall
2- Belt truss along the four sides of the building connected columns (lets say 2 bays each side) provided in one floor

 

[KootK]

If possible, I'd check with your local building code official before going to far with the concept.

I don't feel that either option satisfies the intent of the code provision. The outrigger trusses are worthless if the core walls fail so I don't feel that system adds much to the overall redundancy of the structure. The one story belt truss system only adds redundancy at one story and could be argued to effectively create a vertical stiffness irregularity within your building which may well make things worse seismically.

You might want to look into performance based design as an alternative. If it allows you to stick with a core wall only system, it may well prove the most economical solution.


The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[ahmedhegazi]

Well said KootK , i tend to agree with your point of view.

Another question ,Did you manage to do performance based design for shear wall building before? if yes what software package did you use?

and what element type did you use to model wall non linear behavior?

 

[KootK]

Sadly, I haven't yet had the opportunity to do a serious performance based design myself. All that I know of it I've gleaned from textbooks and case studies. The software Perform 3D from CSI seems to be the dominant offering in that arena. As for the element choices, I'm not sure that I can provide meaningful help. Having the ability to readily define complex material stress-strain curves and report curvatures and hysteresis loops will be important. I've thumbed through the user's manuals for Perform 3D. I suspect that you'll find much of what you need either there or in the documents that the manual references.

Hopefully you'll be around to help me sort things I out when I finally get a chance to try my hand at this!

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 that I want to either change it or adopt it.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[ahmedhegazi]

Kootk , apologize for late reply as i was on business trip , i am now starting looking at this Non linear procedure , dark road but have to go through it .
i am trying to use Etabs 2013 for that .

sure , you can post your question if you need any assistance at time you start with non linear procedure