Lift Shaft Design (Composite Structure)

[Yasir Saleem]

Hello Everyone,

 

I am wandering if somebody guide me through the design of lift shaft for composite Structure. By composite i mean two existing walls are RCC one will be back wall and one side wall. Other two will be steel walls and opening is in steel wall. I have asked for the structural details of the existing RCC walls to check there steel and if they are designed as shear walls or not. I have to add the steel walls to make a shaft. I want help if i have to check the steel walls what should be my approach as it is not high rise its just a two storey building and lift will be GF plus FF only. the loading i have to consider is hoist load on the top of the walls which more or less behave like point load and i have to chk this for dynamic loading for vibrations that can cause or not later about the lateral loading. I think the connections will be simple as there will be no such great moments so i assume them pin connections. Loading for the diaphragm beam should be the slab load if there any and lateral loading. Bracing for the wall for lateral load.

What about connections between RCC and steel should i keep them also pin or fixed with moments because what i am thinking that if the hoist is placed on RCC and steel wall then it will create the moments at the connection. So it has to be fixed. but then in that case the RCC wall should be able to resist the loading applied at that point.

 

Please go through these points and suggest me what should i do. And yes if some one have any kind of design data or calculation example for lift shafts that will be great help.

 

Regards.     . 

[Ayesha]

Hello Everyone,

 

I am wandering if somebody guide me through the design of lift shaft for composite Structure. By composite i mean two existing walls are RCC one will be back wall and one side wall. Other two will be steel walls and opening is in steel wall. I have asked for the structural details of the existing RCC walls to check there steel and if they are designed as shear walls or not. I have to add the steel walls to make a shaft. I want help if i have to check the steel walls what should be my approach as it is not high rise its just a two storey building and lift will be GF plus FF only. the loading i have to consider is hoist load on the top of the walls which more or less behave like point load and i have to chk this for dynamic loading for vibrations that can cause or not later about the lateral loading. I think the connections will be simple as there will be no such great moments so i assume them pin connections. Loading for the diaphragm beam should be the slab load if there any and lateral loading. Bracing for the wall for lateral load.

What about connections between RCC and steel should i keep them also pin or fixed with moments because what i am thinking that if the hoist is placed on RCC and steel wall then it will create the moments at the connection. So it has to be fixed. but then in that case the RCC wall should be able to resist the loading applied at that point.

 

Please go through these points and suggest me what should i do. And yes if some one have any kind of design data or calculation example for lift shafts that will be great help.

 

Regards.     . 

You should share your floor plans to give an idea of what you are trying to do. It will help others look for solution other than what are proposing.

[UmarMakhzumi]

Hello Everyone,

 

I am wandering if somebody guide me through the design of lift shaft for composite Structure. By composite i mean two existing walls are RCC one will be back wall and one side wall. Other two will be steel walls and opening is in steel wall. I have asked for the structural details of the existing RCC walls to check there steel and if they are designed as shear walls or not. I have to add the steel walls to make a shaft. I want help if i have to check the steel walls what should be my approach as it is not high rise its just a two storey building and lift will be GF plus FF only. the loading i have to consider is hoist load on the top of the walls which more or less behave like point load and i have to chk this for dynamic loading for vibrations that can cause or not later about the lateral loading. I think the connections will be simple as there will be no such great moments so i assume them pin connections. Loading for the diaphragm beam should be the slab load if there any and lateral loading. Bracing for the wall for lateral load.

What about connections between RCC and steel should i keep them also pin or fixed with moments because what i am thinking that if the hoist is placed on RCC and steel wall then it will create the moments at the connection. So it has to be fixed. but then in that case the RCC wall should be able to resist the loading applied at that point.

 

Please go through these points and suggest me what should i do. And yes if some one have any kind of design data or calculation example for lift shafts that will be great help.

 

Regards.     . 

 

Yasir, from the above quoted description, I assume that the present wall is a L- Shaped Wall.  A reasonable solution for a G + 1 or 2 floor building would be to provide a concrete column at the opposite corner to the L-Shaped wall and connect it with exisiting concrete walls through beams. For G + 1 or 2 floor building that would be sufficient. Similar option should follow for steel.  Assuming your present wall configuration is adequate for lateral loads, I see no point in providing steel walls. Depending of the weight of lift and what fdn layout you have, you should be fine with the single column option with beams connectng or bracing into the exisiting wall for concrete/ steel.

[Yasir Saleem]

Sorry for being late in reply, I am attaching the drawing which i got from the contractor till now. I hope they will give me something in good shape soon but at the moment to have an idea this is it. Sir umer my first suggestion was to provide the concrete column and beam but they say no to it. In this drawing you can see i have proposed some elements. I hope they will be more or less working. I will use bracing if i need from calculations. But i just want to confirm the checks which we apply to make sure that in any case of vibration of dynamic loading it is safe. So that is why i am looking for some example.

Scanned copy.pdf

[UmarMakhzumi]

Sorry for being late in reply, I am attaching the drawing which i got from the contractor till now. I hope they will give me something in good shape soon but at the moment to have an idea this is it. Sir umer my first suggestion was to provide the concrete column and beam but they say no to it. In this drawing you can see i have proposed some elements. I hope they will be more or less working. I will use bracing if i need from calculations. But i just want to confirm the checks which we apply to make sure that in any case of vibration of dynamic loading it is safe. So that is why i am looking for some example.

 

You can consider the impact factor and augment your forces for the case of the start and stopping of lift.  There would be no significant continuous dynamic forces. I dont have any calculation examples that cover this.  If anyone else has that please post.

 

Your supporting members are super stiff axially. I am having a hard time accepting that the operation of the lift would produce any significant dynamic effects in the subject case for reasons explained above. I have designed lift cores considering impact but not any dynamic effects. If you get any examples, do share here too.

 

Thanks.

[Yasir Saleem]

sir g thanks for guidance, Actually i am not sure for the dynamic loading but that was my question that if there is some force how we take it and what factor should be there but if there is no need for such loading i am ok with it, but that was my query i was just wandering... But ok i will do it accordingly as one of my course mate from Brasil also explained the same you are telling me so no big issues let me go with that.

[UmarMakhzumi]

sir g thanks for guidance, Actually i am not sure for the dynamic loading but that was my question that if there is some force how we take it and what factor should be there but if there is no need for such loading i am ok with it, but that was my query i was just wandering... But ok i will do it accordingly as one of my course mate from Brasil also explained the same you are telling me so no big issues let me go with that.

 

Okay, Super.

 

Thanks.