Behaviour of Modular Precast Buildings

[GalileoG]

I am designing a 15 storey modular precast building (for pricing) and was wondering how the lateral behaviour of the building differs from that of a cast-in-place structure. Each module is three sided.

Several questions came to mind:

Will or should all of my walls in my module be designed as shear walls? Can I pick and choose which walls is to be a shear wall and design its reinforcing accordingly or am I forced to treat all walls as shear walls? The floor and roof of each module will act as a diaphragm, then I suppose they should be treated as a series of simply supported beams. If so, wouldn’t I have to treat all my walls as shear walls? You would say that it depends on the connections between each module but it looks like that they will be grouting the edge of the bottom slab of the module to the roof slab of the module below it. It does not appear that they are going to grout each module to its adjacent module. Surely this can not be typical practice, is it? That does not seem right at all. How about the seismic behaviour of modular precast buildings. I would think that they would not behave too well under seismic loads?

Again, this is for pricing only, I will not be going into detailed design here but I would nevertheless appreciate any comments however much indepth it is into modular buildings.


Clansman

"If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[WpgKarl]

Can you sketch what your bldg looks like in plan & section?

 

[Teguci]

If its stiff it will take lateral seismic loads. If you are looking to isolate some of the walls from taking the lateral loads you will get yourself into a detailing nightmare since you can't disconnect the walls from the diaphragm.

Speaking from the perspective of modular precast garages, the goal of the seismic bracing system is to make the structure as stiff as possible - flexible frames are not encouraged.

Therefore, the use of either a welded plate connection or NMB splice is suggested between all of the connections between walls.

Except for eccentric bracing, I can't think of a reason to disconnect the walls.