Automated stairs with ilogic

[Jon.CoxYDTZY]

Hi, I've been trying to create a stringer stair assembly which is automated in terms of a platform height is entered and then the optimum sizes for stair tread and rise are calculated where certain conditions are met according to the specification.

My criteria is the Step Rise is to be between 170 - 220mm, tread depth between 250-400mm, stair angle between 38 - 42. there's also a tread overhang criteria which needs to be between 16 - 40mm and i want my overall tread depth to be a constant at 283mm as this works with the flooring type we use.

The attached model regenerates for given inputs and flags up warnings when outside the criteria but what i'd like is to use some programming to find the values which work. Does that require loops..? Started to look at excel solver but can't quite get my data set to work. Any assistance would be appreciated. 

[torbjorn_heglum2 · Accepted solution]

Hi, I do some design of stairs and walkways and this this is and interesting case.

I think you don't need too much solving with the criterias you describe:

- Rise is independent of the other criterias.

- With a fixed tread depth, the overhang is a function of the stair angle.

- With a tight variation of the stair angle, the overhang criteria might not be fulfilled.

I made a version of this stair, where all design intent and all details is controlled by a single master model. The parts and the assembly are pretty simple, with no added design information. In the assembly I added a simple ilogic snippet and a form to set up the stair parameters.

The rise is defined by dividing the height by the middle value of the rise criteria, then round this value to the nearest integer to find the number of steps required. Then the actual rise is calculated by dividing height by the number of steps. Here it is done by parameter formulas, but could of course as well be ilogic. If tread width was variable, I would probably do something similar but comparing with the overhang.

The no of stanchions will also increase if the horizontal distance passes 1500 mm. But will collide with steps in some cases, as they are just evenly spaced.

The master model is placed as a reference in the assembly, to control added instances of parts. The first instance of all parts are grounded, and the next instances by associative patterns or rigid joints to the master model.

The master model based stair is attached, IV2019

Torbjørn

[IgorMir · Accepted solution]

Hi Jon;

For what it worth - here is a set of files for a stairway. The whole project was created for some different purposes (not for fabricating of the stairways) but it might give you some ideas.

The file Stairway.ipt controls the whole assembly. In there modify d0, d1, d4 parameters and save it. Open up Master.iam and rebuild it a few times to see all the changes to the design. Files are in IV2020 format.

Cheers,

Igor.

[Jon.CoxYDTZY]

Thanks Torbjorn, I think I  had over-complicated the problem with my model, yours seems much simpler and works for what we need to do. I can add the fabrication drawings to this and make it all re-usable.

Happy new year! 

Best regards,

Jon 

[Jon.CoxYDTZY]

Hi Igor, thanks for the model, we are building this type of structure as well and I was thinking to build in the landing once predetermined height/no. of steps reached according to the standards with another master model and then bring in the next flight of stairs. 

Happy new year!

Best regards,

Jon