Expansion joint vs building drift at top 1

[canstruct]

Hi Guys,

Need clarification, when we have two buildings separated by expansion joint of 2"(normally). How does we can strict these buildings for 1" max. deflection. It is difficult with moment frames. For steel building with bracing it is ok but with moment frame, building deflection cannot be limited which maximum is for my case look like 1" only. Can we assume more deflection at top or we can just check for drift.
Appreciate for comment.

 

[msquared48]

Use a bigger expansion joint... 4 or 6" is not unheard of.

Mike McCann
McCann Engineering

 

[slickdeals]

And remember to check your deflection at design loads and amplify with Cd.

 

[whyun]

The building separation is explicitly calculated per governing code (latest is ASCE 7-05 Section 12.12.3 which refers to Section 12.8.6). Actual separation is then rounded up to the next inch or two.

In dealing with existing structures, assumption is that the existing separation has been correctly calculated per the prevaling code at the time the buildings were designed. You may still verify, time and money permitting.

I don't know how many stories your buildings are, nor the specific situation that warranted yor question but 2" separation for two moment frame buildings does not look correct.

 

[Rejido]

In our building, it's 150mm seismic gap.

 

[ali07]

Is your building is a steel building or concrete. How you dealt with that expansion joint.