Steel Bridge between buildings

[Sujitha Menon]

I am designing a bridge between 2 buildings. the
The building is 7 stories and a 30m link bridge is required at level 3,4 5 and 6.between the buildings
The building has expansion joint on one side of bridge which will be accommodated via a slotted connection on one side
1)Can I consider the bridge not as a part of lateral Load Resisting System? and design bridge separately and apply point loads?
2)While Designing the Steel bridge in Etabs-ASCE 7-16 can I use the same R ,Omega and Cd values input for concrete as the Major model is a concrete structure and steel is designed only in a small area
3)How about amending the R omega and Cd values in steel design Parameters?
4)As per ASCE table 12 what is the value that I should consider for Steel Trusses?

 

[dik]

It's pretty straight forward. You have to account for new loading on the existing buildings, including lateral. You need to accommodate thermal expansion, fixed at one end and sliding at the other. Consider using teflon bearings. You also need a good expansion joint. You can buy a cheap one, or one that works. You have to look at penetration of the building envelope and maintain a weathertight seal between the bridge and the buildings.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[Sujitha Menon]

Thank u
please note that these are not existing buildings
but new buildings with link bridge in between
just about R omega and Cd value of steel bridge

 

[dik]

I've done several of these... and never treated them like 'bridges', always as structures and designed them accordingly.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[KootK]

I dealt with similar issues on the building below and found it to be rich with complexity regarding constructability, thermal movements, and lateral design. I'd be happy to attempt to help with this but I would need to know quite a bit more about the details of your situation. Can you post:

1) A basic building elevation perpendicular to the bridge(s).

2) Your understanding of the boundary conditions of the bridges at each end?

For conventional connector bridge detailing, it can be quite difficult to avoid the lateral / torsional coupling issue shown below. In my case, we wound up abandoning the bridge movement joints entirely for this reason and, instead, rigidly connecting the two buildings across the bridges. But, then, our bridges were about half as wide in plan as the buildings themselves which facilitated this. With a bridge skinny relative to it's floor plan width, a different solution would likely be required. A single, central pivot point on the fixed end might be neat.