LIFT DESIGN

[Dan.M.M]

I want to design a lift shaft that has a machine room on top. Can someone aid me in providing a visual description of how the motor weight will be distributed to the shear walls? Also, does it behave the same as load distribution on the beam whereby I divide it into a trapezium

 

[sdz]

Do you have a layout?

Ooo eee ooo ah ah ting tang walla walla bing bang
Ooo eee ooo ah ah ting tang walla walla bing bang

 

[JLNJ]

I would expect that the head house would have beams directly under the lifting/counterweight mechanism (the beams are often oriented on the diagonal). I've seen it where the head house slab is cast between the beam flanges so that the top of the flange is exposed. It all depends on the geometry of the head house machinery.

As to how the seismic weight gets to the shear walls, I would think the machine room slab would be more than adequate as a diaphragm.

 

[Dan.M.M]

this is the layout

 

[Dan.M.M]

@JLNJ, the building is a 4 story thus I won't be designing for seismic loads, and the area I'm in is determined as low to shallow seismic hazard. Okay, then the beams would transfer the loads to the edge of the shear wall. I have a question on that won't it cause some sort of eccentricity?

 

[jayrod12]

Eccentricity in what sense? You would need to account for the load where it is applied with either your known eccentricity from the connection detailing, or the minimum eccentricity as required by your code.

What material are your 300 wide walls?

 

[Dan.M.M]

reinforced concrete walls

 

[Dan.M.M]

Eccentricity in the sense that when you load the shear wall at the edge instead of the center when you place the beams diagonally.

 

[JLNJ]

Normally, I extend the beams for enough onto the wall(s) so that the eccentricity is minimized. Unless your load is gigantic, you can probably detail it so that it is centered up.

 

[jayrod12]

The load from the lift beam usually applies only a gravity load to the wall. So you would treat it as a point load on the top of the wall. I don't see the eccentricity from the beam being diagonal playing into your wall design from a lateral sense.