# Concrete Design – set up and using the addon

**URL:** <https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004>\
**Category:** Product Support\
**Tags:** reinforcement, addon-concrete-design, modeling\
**Created:** [March 4, 2026, 10:44am UTC](https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004 "2026-03-04T10:44:02Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Marko0225](https://community.dlubal.com/letter_avatar_proxy/v4/letter/m/7993a0/32.png) [@Marko0225](https://community.dlubal.com/u/Marko0225)\
**Post date:** [March 4, 2026, 10:44am UTC](https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004/1 "2026-03-04T10:44:02Z")

</div>

Hi everyone. I’ve downloaded the RFEM student version and I’m trying to figure it out. At first glance everything is simple: I created a model, assigned materials and sections, defined supports, applied loads. Everything is great — clear, fast, and straightforward.

Then I started learning the reinforced concrete add-on, and here I’m running into a lot of issues. I can’t find a detailed description of the “Edit ultimate configuration” dialog and other “Concrete design” dialogs. I guess I’m entering something incorrectly there, because “Required reinforcement” always matches “Provided reinforcement”.

I reduce the rebar diameter in a beam, recalculate — and again “Required reinforcement” equals “Provided reinforcement” (and all design check utilization factors are OK). If I reduce the reinforcement even more (down to a minimum), “Not covered reinforcement” appears, but all design checks are still OK.

Please help me set up the design so that:

- “Provided reinforcement” shows the reinforcement I actually defined in the members,
- “Required reinforcement” shows the minimum reinforcement that satisfies all checks,
- “Not covered reinforcement” shows the difference between those two.

Also, when I look at internal force diagrams, everything looks fine (even with seismic loads). But the “Required reinforcement” diagram looks illogical: there is top reinforcement in midspan (and it is even larger than at the support), etc.

And one last question: is it possible to obtain the reinforcement envelope (Required reinforcement) selected according to all checks specified in Concrete design without defining reinforcement in the members?

---

<div class="post-metadata">

**Author:** ![sandy.matula](https://community.dlubal.com/user_avatar/community.dlubal.com/sandy.matula/32/107_2.png) [@sandy.matula](https://community.dlubal.com/u/sandy.matula)\
**Post date:** [March 4, 2026, 12:39pm UTC](https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004/3 "2026-03-04T12:39:39Z")

</div>

Hi Marko0225,

thanks for your message!

To analyse the problem more precisely, the **model file** would be very helpful:

➡ Click on _File_ → _Save as_ and choose the following settings to reduce the file size:

 ![image](https://community.dlubal.com/uploads/default/original/1X/c663e26274a82716c5dc1d6e03f34c9b01cafc83.png)

➡ Then upload the file here (e.g. \*.rf6, \*.rs9) – this way, the community can also contribute to the solution.

🦉 Prefer not to share the file publicly? No problem – send it to me via direct message: click on my _profile picture_ or _user name_ → _Message_.

Best regards  
Sandy Matula

---

<div class="post-metadata">

**Author:** ![Marko0225](https://community.dlubal.com/letter_avatar_proxy/v4/letter/m/7993a0/32.png) [@Marko0225](https://community.dlubal.com/u/Marko0225)\
**Post date:** [March 4, 2026, 2:29pm UTC](https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004/5 "2026-03-04T14:29:34Z")

</div>

Dear Sandy, thanks for the reply, here is the file and 1 more question regarding concrete design and  
[projekat.rf6](https://community.dlubal.com/uploads/short-url/hB1fLxKvI2axJ5qRuK3mc2ytjK1.rf6) (2.4 MB)

 ![image (54)](https://community.dlubal.com/uploads/default/original/2X/b/b8d16651b5b27e725957d76245eee503075997bb.jpeg)  
This is the Required reinforcement for the calculation considering seismic loads. The most interesting thing is that the maxima clearly coincide with the installed reinforcement. All checks are passed.  
But if you increase the reinforcement from 20 mm diameter to 28 mm diameter (and change nothing else)…

---

<div class="post-metadata">

**Author:** ![Marko0225](https://community.dlubal.com/letter_avatar_proxy/v4/letter/m/7993a0/32.png) [@Marko0225](https://community.dlubal.com/u/Marko0225)\
**Post date:** [March 4, 2026, 2:31pm UTC](https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004/6 "2026-03-04T14:31:38Z")

</div>

Regarding the problem above, here are additional images

 ![image (56)](https://community.dlubal.com/uploads/default/original/2X/a/af64f0649145cebedae9e95e9910c65e91001bbf.png)  
 ![image (55)](https://community.dlubal.com/uploads/default/original/2X/6/6d2295f08242f5ca7242584b9495cf30bcdadb87.png)

By changing only the diameter, we get a higher Required reinforcement. How can we determine the minimum reinforcement that satisfies all checks?

---

<div class="post-metadata">

**Author:** ![Marko0225](https://community.dlubal.com/letter_avatar_proxy/v4/letter/m/7993a0/32.png) [@Marko0225](https://community.dlubal.com/u/Marko0225)\
**Post date:** [March 4, 2026, 3:05pm UTC](https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004/7 "2026-03-04T15:05:23Z")

</div>

Here's one more attachment that shows higher required reinforcement after changing the diameters

 ![image (57)](https://community.dlubal.com/uploads/default/original/2X/a/ab58b418c4221220076c883e5bd8c32b048e7aec.jpeg)

---

<div class="post-metadata">

**Author:** ![juliane.stopper](https://community.dlubal.com/user_avatar/community.dlubal.com/juliane.stopper/32/128_2.png) [@juliane.stopper](https://community.dlubal.com/u/juliane.stopper)\
**Post date:** [April 15, 2026, 9:24am UTC](https://community.dlubal.com/t/concrete-design-set-up-and-using-the-addon/3004/9 "2026-04-15T09:24:49Z")

</div>

Hi Marko0225,

thanks for your post.

1. I checked your model. The observed behavior is caused by the settings in the ultimate configurations. You selected the option **“Use provided longitudinal reinforcement”** for the required shear reinforcement. If you switch to the default option **“Use required longitudinal reinforcement”** , the results should match your expectations.

2. Automatic reinforcement design is also available for members. The following Knowledge Base article describes the feature for surfaces; for members, it works analogously. [https://www.dlubal.com/en/support-and-learning/support/knowledge-base/001842](https://www.dlubal.com/en/support-and-learning/support/knowledge-base/001842)

Best regards,

Juliane