re: 7 storeys mid- rise

[mronlinetutor]

I have completed a model of 7 stories mid-rise concrete moment frame.

Attached is my first report.

spacing of column
10'x10'

girder size
3'x4'

girder length
30'

room size
30'x30'

column size
3'x3'

concrete slab
10"

roof slab
12"

matt foundation
4'

shear wall
32"

Only the girder size and column size are checked.

Can you see anything wrong with it?

Thank you very much.

From

Stanley.


disclaimer: all calculations and comments must be checked by senior engineers before they are taken to be acceptable.

Please note there is an update on girder length and room size.

 

[dhengr]

Mronlinetutor:
Why not just make all of the main beams full story high beams, about 12” thick. Think of all the columns and shear walls you would save. The forming would be much cleaner too.

 

[mronlinetutor]

To dhengr,

Thanks. I would size down the interior beams. Instead of making the interior beams the same size of the girder, I will size it down.

disclaimer: all calculations and comments must be checked by senior engineers before they are taken to be acceptable.

 

[mronlinetutor]

To r13,

I did not put the stairwells to the elevator shafts is because of architural purpose. I want the tenants to be able to walk to the elevator doors as quickly as possible. Sometimes, the tenants have to walk around the elevator shafts to the elavotor doors situated on the opposite side when the elavators are full.

disclaimer: all calculations and comments must be checked by senior engineers before they are taken to be acceptable.

 

[mronlinetutor]

To MIStrucE IRE

The columns are actually on a 30' by 30' grid. The beams are sitting on a 10' spacing. The connection joining the beam to the girder has a column above aand below the connection. These connection are often spaced 10' apart.

Yes, the beams should only be reinforced with bottom bars at the center and reforced with top bars on both ends due to hogging moment at the support. The doubly reinforced bars are to satisfy the shear condition.

The shear wall can be 24" thick. But I am afraid of soft storey where a 3' wide beam or girder sitting on a 24" shear wall. So I made the shear wall 32".

The stirrups are not designed yet. The stirrups is only a number for Midas Gen to initiate the building model.

disclaimer: all calculations and comments must be checked by senior engineers before they are taken to be acceptable.