Iterative calculation - trying to find "cN and cP" by iteration (It ranges from 0 to tH).

[Huy_Nguyen]

I had a similar problem but was quite confused to deal with it. It would be great if you can help me solve it.
Please take a look attached file from steps 5 to 9. I'm trying to find "cN and cP" by iteration (It ranges from 0 to tH).

Please help me give a solution for it. Thank you so much.

[SPRstructur]

Dear Huy

I am not clear your problem. but I think you should do it as symbolic solution or the equation consist of (cN, cP and tH ) as variables and then apply equilibrium. to do this no need to iteration, in Mathcad prime have build-in function or other methods to solve that.

Thank you

[SPRstructur · Accepted solution]

hello Huy

here is a solution of your problem Retrofit concrete-Slab 

Enjoy

SPR-kh

[Fred_Kohlhepp]

SPRstructor;

Your sheet with a few minor changes see light green:

Will now run in Express, still saved in version 8 but would run in Prime 4.0 Express.

[LucMeekes]

Here is Fred's file converted to Prime 7 so the OP can read it.

Success!
Luc

[Huy_Nguyen]

Thank you for enthusiastic help

[Huy_Nguyen]

I am very grateful for your enthusiastic help

[Huy_Nguyen]

It works. Thank you so much. Have a nice day.

[Huy_Nguyen]

I followed your solutions to develop and optimize my calculation. Unfortunately, it was not going well by using "solve block" and "function" as well. Do I missed something?

I really appreciate if you can help me solve it. Thank you so much.

[SPRstructur]

Huy

check your Origin set =1 and 

check your mid-span again I see you missed somethings from pic above 

[SPRstructur]

Other method without change Origin (but in further , you should make sure your Origin (1 or 0)) and I had corrected your input (Yellow)

Enjoy

SPR-kh

[Huy_Nguyen]

Thank you so much for your help. Please forgive because of my shallow understanding. Unfortunately, my Mathcad prime version is 7.0 so I cannot open your attached file. I tried to fix it follow your recommend and I can achieve with cN but there is a mistake with cP and input parameter (in yellow)

Can you tell me why or send to me a lower version file. Thank you so much.

[SPRstructur]

I have deleted my 7.00 reduce my computer load. But I think everyone here will help you

if you are in hurry I can print screen for you and attach pdf

this point pleas ignore 

In fact, I am in your field as well. I have a question.

why does your calculation of neutral depth at mid-span relate to strain at support ?
I think should be relate to strain at mid span.

SPR-kh

[Huy_Nguyen]

Thank you so much. Now, I can fix it by myself. I'm glad to hear we have the same area of interest. I'm fully agree with you neutral depth at mid-span should related to strain at mid-span. I think you are mentioning step 3 of my calculation (related to "epsilon_bi") or please let me know what get you misunderstanding my ideal. Actually, it relates to my retrofitted structure and "epsilon_bi" is only used to estimate neutral axis depth at support based on ACI440.2R report. And, we don't need to consider it for mid-span case.

My pleasure to introduce some information relate to my retrofitted structure.

Now, I am trying to optimize overlay thickness of retrofitted slab based on a new methodology to induce ductile failure. Recently, I realized Mathcad can help me make it faster. I am new to using Mathcad and fortunate to have the support from you as well as the ptc user community. I'm so grateful for that.

By the way. I think the height of flexural RC members should be limited due to its self-weight and efficiency. But I'm having trouble finding articles and standards that cover this issue. It would be great if you could give me advice or information on this.

Thank you.

[SPRstructur]

yes "epsilon_bi" at mid-span should calculate at mid-span if we add CFRP under slab at mid span. if you calculate at support ,yes.

we can use Mathcad to optimize our solution. it is my pressure I will help you as​ I can. I know that feel, especially waiting solution from community. I needed much time learn day by day  and ask a lots questions here until I can be clear with it and do it by self.

my topic wasn't related to your topic but I used to read retrofit slab topic. I am not clear in mechanism and property of CFRP but I think after we know that stuff we can apply equilibrium like RC member.

can you tell me what your conclusion? optimize slab thickness? location of CFRP? Load Limitation on existing structure?

[Huy_Nguyen]

Yes, of course. Actually, we are not in first step. Optimal CFRP can be achieved through some our publications. Now, my topic is optimal overlay thickness (slab thickness also) of continuous slab

[SPRstructur]

if I don't confuse , Sika product or other they have suit for calculating. you can check in that product.

Look at this: https://gcc.sika.com/en/documents-resources/sika-carbodur-frp-design-software.html

[LucMeekes]

Unfortunately this trick doesn't work as such in Prime 7:

While Prime 8 allows:

Prime 7 goes:

You can circumvent this part by setting the product range explicitly, but:

Success!
Luc

[SPRstructur]

oh nice @LucMeekes  I don't know Mathcad prime 7.000 can't do as 8.000. best update of 8.000

[Huy_Nguyen]

Your comment is really meaningful to me. It makes me quite confuse. Thanks a lot.