Bridge between new and existing building

[n3jc]

Hello guys.

Im designing a new construction (with a terrace on top) next to existing building.
Investor would like to connect new and existing building by concrete slab - bridge.

Im wondering... it may be smart to make a dilatation of some kind between new building and a bridge. If I connect it fully (existing building + bridge + new building) I suspect that lateral load will be transfered from one building to another + new building will have torsional swing form in case of earthquake which Id like to avoid... I also have no data about existing building so id like to avoid that as much as possible.

Im even wondering about making a steel bridge, but it was said it should be concrete... i think it would be better.

Any suggestions?

 

[KootK]

It sounds as though you're on the right track. Providing a movement joint at the existing building is a common approach for a number of reasons including lateral and thermal separation. Depending on the capacity available at the ecisting building, sometimes a column or two are also provided nearby to reduce the need for carrying gravity load at the existing building.

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.

 

[canwesteng]

Is there any appetite for bracing it off your structure, like a drawbridge? That way it kind of floats above the existing structure. That would be my preference anyway.

 

[Lomarandil]

Absolutely -- provide at least lateral separation between the two. You should be able to tie any forces back into your new structure more easily and economically than dealing with the existing building.

As for steel vs concrete -- lots of considerations at play. Owner's preference rules, of course. You may be able to sway that if constructability, contractor experience, weathering concerns etc can be translated into an overall cost savings.

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The name is a long story -- just call me Lo.