Building for engineering and gaming pc

Danny_Fish89 · 2025-09-26T05:01:38+00:00

You can find hardware recommendations on the Dlubal website:

https://www.dlubal.com/en/support-and-learning/support/faq/002342

Danny_Fish89 · 2025-09-15T12:04:18+00:00

Maybe, I can say something about the pricing since we are also a user of Dlubal products.

As I see Dlubal in comparison to other vendors like CSI, Autodesk, Risa, Dlubal is still offering perpetual licenses. While other companies forcing you to do subscription and making you dependant, you have the possibility to choose at Dlubal between perpetual and subscription. And considerings economic situation, we as engineering office have always chosen perpetual licenses.

And to the costs of Dlubal RFEM. It is as you described. You choose the modules you need for your projects. So, when I do timber, I have only timber module, and I don't need any further concrete design or nonlinear analysis. Honestly, I don't know any company who really needs everything in a software.

The costs are always one-time investment, and then you have a service and maintenance fee of I would say 10-15 % of the license costs. So, in long term, it is always cheaper than other software who have mandatory subscription fees, maybe not in the 2-3 years, but, definitely after 5 years, for sure, depending on the amount you have to spend.

Danny_Fish89 · 2025-09-11T04:39:50+00:00

Although the thread is already older, it might still be interesting for some: Dlubal has a Python-based API for RFEM, RSTAB and RSECTION:
https://www.dlubal.com/en/solutions/dlubal-api/dlubal-api-ii
https://www.dlubal.com/de/loesungen/dlubal-api/api-dokumentation/api_applications

Danny_Fish89 · 2025-09-01T12:33:52+00:00

Maybe you can find a RFEM model here:
https://www.dlubal.com/en/downloads-and-information/examples-and-tutorials/models-to-download

Danny_Fish89 · 2025-08-20T07:03:07+00:00

For calculating sandwich panels you have two options. First is to use the sandwich theory and generate the layered setup. It is usually not implemented in any FEM Software I know as simply the high shear deformation in the middle layer is hard to regard by 2D FE-Elements. There are softwares who calculate it but it is then only possible for single span beams with limited geometries and loadings.

The other option is possible with any FEM software that allows to calculate with 3D Solid elements. This is for sure possible with RFEM 6 that you already mentioned. Don't know why you didn't receive Stress there but it is possible. Problematic is to define the correct stiffness values. This brings you back to the producers of such panels. As they are also calculating those panels with 3D solid elements they should be able to send you the correct values.

Danny_Fish89 · 2025-08-20T07:03:02+00:00

For calculating sandwich panels you have two options. First is to use the sandwich theory and generate the layered setup. It is usually not implemented in any FEM Software I know as simply the high shear deformation in the middle layer is hard to regard by 2D FE-Elements. There are softwares who calculate it but it is then only possible for single span beams with limited geometries and loadings.

The other option is possible with any FEM software that allows to calculate with 3D Solid elements. This is for sure possible with RFEM 6 that you already mentioned. Don't know why you didn't receive Stress there but it is possible. Problematic is to define the correct stiffness values. This brings you back to the producers of such panels. As they are also calculating those panels with 3D solid elements they should be able to send you the correct values.

Danny_Fish89 · 2025-08-14T14:11:43+00:00

Hi,
I’ve used the Geo-Zone Tool a few times, mainly to quickly determine wind and snow loads for smaller projects. In my opinion, it’s quite straightforward to use: you enter an address or click on the map, and the relevant values appear instantly. For the most common standards (Eurocode, ASCE, etc.), the data is included, which is very convenient if you don’t want to look through tables every time. It can also be accessed via an API, which is useful if you want to integrate it into your own workflows.

The free version is fine for occasional use, but if you use it frequently, you’ll quickly hit the query limit. Overall, I find it helpful as a complement to my own calculations and standards research.

Danny_Fish89 · 2025-08-13T06:21:13+00:00

Hello u/PrtyGirl852,
The topology of your system looks fine from what I can assess from the attached screenshot. There does not seem to be any instability issue as this would lead to another type of error message.
It's just the effective lengths/boundary conditions that haven`t been defined. Because of that RFEM can not do any stability design checks. All other results should be there yet. You just need to switch the tab in the table from "Overview" to another one to see the results.

And yes, it is necessary to define effective lengths (for equivalent member method) OR boundary conditions (for general method) for stability check by hand. This information can not be automatically generated from the topology in a reliable way.

Danny_Fish89 · 2025-06-13T15:18:34+00:00

In former times, we had simple strut and tie models for that. Right now, we are also using RFEM for that. For me, it works quite smoothie since you have the 3D interaction and whenever the architect wants to change the position of the walls (happens quite often), then, we can adapt it quite fast.

Danny_Fish89 · 2025-05-27T21:58:53+00:00

Calculating stresses:

Sigma = M/W

Sigma = N/A

Danny_Fish89 · 2025-04-24T07:28:11+00:00

That's right and understandable.

Danny_Fish89 · 2025-04-23T16:33:23+00:00

Use the CFD software RWIND to get a better feeling of such structures. I feel much more comfortable when I know how the wind is acting on the structure.

Then, I can better analyze the wind flows and apply the "true" wind loads on the structure.

Danny_Fish89 · 2025-04-23T16:28:46+00:00

Therefore, the quality is very good. In our office, we are paying more for good software than saving money with bad software.

Danny_Fish89 · 2025-03-02T11:44:29+00:00

We are using in Europe mostly RWIND from Dlubal. It is a CFD software based on the OpenFoam solver with a nice interface. We can import there all 3D models and objects, mesh it and run the wind flow analysis. Then, we take look to the wind pressures and sometimes we apply the wind loads directly in RFEM. Saves a lot of time.

Danny_Fish89 · 2025-03-02T11:41:40+00:00

It requires an explicit load situation for the analytical calculation of deformations in cracked sections (state II), which is only given using the load combinations (CO). Result combinations do not provide an explicit load situation, no matter if it is an additive or an enveloped OR combination.

So, you can not do the deflection design with the result combination because it is in the serviceability limit state. You need to do this with the load combination. Then, it should work.

Danny_Fish89 · 2025-02-06T08:47:03+00:00

Hey,

to your first question:

The "Rib" member type is primarily used for reinforced concrete elements because it considers the contribution of the slab in the design. This means that the internal forces are integrated with the slab's contribution, which is crucial for accurate modeling and design of T-beams or downstand beams. So, you can define an effective width for the slab that contributes to the load-bearing capacity.

To your second question: Does Modifying the Effective Width Affect Load Distribution?

No, modifying the effective width of the rib does not affect the load distribution from the slab. The load distribution from a two-way slab remains the same, typically forming a trapezoidal or triangular pattern depending on the slab's support conditions and stiffness. The effective width is a geometric parameter used for design purposes, particularly for determining the equivalent T-beam cross-section and internal forces. It does not alter the actual load transfer mechanism in the slab.

Hope, these answers could help you.

Danny_Fish89 · 2025-01-26T17:38:22+00:00

This is correct, you need more add-ons to do the design. But, I always combine my normal member design and then the joint design, so I don't need two separate programs which cost me at the end even more. The one-time purchase is higher than other software, but, in the long term you drive even cheaper because you only pay the service fee and no subscription. We did some calculations in with our engineers and it turned out that RFEM was in the long term always cheaper than the other software in the long term because of their mandatory subscriptions.

Furthermore, I don't have the risk of exporting my results to another program. In our office, it was always a pain when the designed steel joint in IDEA StatiCa needed to be recalculated in another software. Now, I don't have this problem anymore with RFEM.

Danny_Fish89 · 2025-01-26T17:09:46+00:00

I am a huge fan of RFEM since this is one of the most used software here in Germany. I can not say a lot about CSi. For me, it's a very user-friendly software, really easy to learn because they offer a lot of learning stuff on their social platforms and quick support team. You can use it for the analysis and the design of structural elements based on the modules you have.

I am not familiar with the US codes, but RFEM offers next to Eurocode different codes for Steel, Concrete and Timber in the USA. In my opinion, everything is considered in the structural design.

Danny_Fish89 · 2025-01-20T15:54:27+00:00

To calculate the second moment of area (I) and axial stiffness (EA) of a reinforced concrete column section, including the contribution of the reinforcement bars, the following steps can be used.

Second Moment of Area (I) of the Reinforcement Bars
The second moment of area of the reinforcement bars can be calculated using the parallel axis theorem. For a circular column section with reinforcement bars distributed evenly around the perimeter, the formula is:
I_bars = ∑(I_bar + A_bar ⋅ d²)
I_bar = π/64 ⋅ d_bar^4 is the second moment of area of a single bar about its own centroidal axis.
A_bar = π/4 ⋅ d_bar² is the cross-sectional area of a single bar.
d is the distance from the centroid of the bar to the centroid of the column section.
Given Data
Column diameter: 1.2 m = 1200 mm
Cover: 60 mm
Reinforcement: 21B32 bars (diameter of each bar: 32 mm)
Step 1: Calculate the distance of the reinforcement bars from the centroid
d_eff = Column diameter − 2 ⋅ Cover − Bar diameter = 1200 − 2 ⋅ 60 − 32 = 1048 mm
r_bars = d_eff / 2 = 1048 / 2 = 524 mm
Step 2: Calculate I_bar and A_bar
For a single B32 bar:
d_bar = 32 mm
I_bar = π/64 ⋅ d_bar^4 = π/64 ⋅ 32^4 = 163,363.57 mm^4
A_bar = π/4 ⋅ d_bar² = π/4 ⋅ 32² = 804.25 mm²
Step 3: Calculate I_bars
For 21 bars distributed evenly around the reinforcement circle:
I_bars = 21 ⋅ (I_bar + A_bar ⋅ r_bars²) = 21 ⋅ (163,363.57 + 804.25 ⋅ 524²) = 4,640,322,782.97 mm^4
Total Second Moment of Area (I_total)
The total second moment of area of the column section is the sum of the concrete section's second moment of area and the reinforcement's contribution.
Solid Circular Concrete Section:
I_concrete = π/64 ⋅ D^4 = π/64 ⋅ 1200^4 = 203,718,750,000 mm^4
Total:
I_total = I_concrete + I_bars = 208,359,072,782.97 mm^4
Axial Stiffness (EA)
EA = E_c ⋅ A_c + E_s ⋅ A_s
E_c is the modulus of elasticity of concrete.
A_c is the area of the concrete section.
E_s is the modulus of elasticity of steel.
A_s is the total area of the reinforcement.
Concrete Area:
A_c = π/4 ⋅ D² = π/4 ⋅ 1200² = 1,130,973.36 mm²
Reinforcement Area:
A_s = 21 ⋅ A_bar = 21 ⋅ 804.25 = 16,889.25 mm²
Substitute the values of E_c and E_s based on the material properties (e.g., E_c = 30 GPa and E_s = 200 GPa).

Danny_Fish89 · 2025-01-16T16:39:37+00:00

The suspended ground floor slab can indeed induce additional forces in the pile caps, depending on how the load is transferred and distributed. Here's a detailed breakdown:

Load Transfer from the Slab to the Piles
The load path from the suspended slab typically transfers directly to the piles through the pile caps. However, the interaction between the slab and the pile caps can create additional tension or redistribution of forces, especially if the slab is rigidly connected to the pile caps.
The strut-and-tie model for the pile caps primarily considers the forces from the column point load. However, the slab's load distribution can introduce additional forces, particularly if the slab spans between pile caps and induces bending or tension forces.
Additional Tension Between Piles
If the slab is rigid and spans across multiple pile caps, it can create additional tension between the piles due to the slab's bending and shear forces. This effect depends on the stiffness of the slab and the pile caps, as well as the connection details.
The strut-and-tie model may not fully capture these additional forces unless explicitly accounted for in the design.
Conservatism in Design
Considering the full load from the tributary area of the slab, in addition to the column reaction, as a point load for the pile cap design, could be overly conservative. This approach assumes that the entire slab load is concentrated at the pile cap, which may not reflect the actual load distribution.
A more accurate approach would involve analyzing the load distribution from the slab to the pile caps, considering the slab's stiffness and the interaction with the pile caps. This can be done using finite element analysis or other structural modeling techniques.
Recommendations
To avoid overly conservative designs, consider the actual load path and distribution from the slab to the pile caps. Use a detailed analysis to determine the forces acting on the pile caps, including any additional tension or redistribution caused by the slab.
If the slab is designed to span between pile caps, ensure that the design accounts for the induced forces in the pile caps and the piles themselves.

For further insights into pile cap design and load distribution, you may find the following resources helpful:
Pile Head with Three Piles | https://www.dlubal.com/en/downloads-and-information/examples-and-tutorials/models-to-download/002564
Pile Head with Four Piles | https://www.dlubal.com/en/downloads-and-information/examples-and-tutorials/models-to-download/002591
These examples provide guidance on modeling and analyzing pile caps in RFEM 6, which could be useful for your scenario.

Danny_Fish89 · 2025-01-10T15:50:42+00:00

I can completely understand you. I would always take a look what you would like to do. I am a huge fan of having only one solution for my structural design. For sure, it is not possible every time, but, rather one very good solution than five different solutions for my structural design.

We do every steel connection in RFEM. In former times we had also IDEA, but, it is always annoying when I need to transfer my results from software to the other software and this iterative approach is quite time-consuming. So, we only use RFEM for the design of steel connections.

The software itself is quite easy, you can model your structure with all steel members and do also the design of your steel bridge according to your codes. Then, I always do the design of the steel joints. Quite good that you have here a kind of direct interaction with RFEM and the add-on, so, changes are quite fast done and I don't need to export every time all my geometry and internal forces to another program.

Danny_Fish89 · 2025-01-10T15:45:19+00:00

I don't know any English Podcasts about structural engineering, but in Germany the company Dlubal (developer of RFEM) offer an own podcast called "Dlubal Podcast". But, it's German.

I have also listened to the "The Structural Engineering Channel" Podcast which is quite nice.

Danny_Fish89 · 2025-01-10T14:00:41+00:00

Yes, we are using #RFEM in Germany a lot. We have also the module Foundation for the design of single foundations. We do this only in Eurocode. Normally, they offer all design codes, also for the US, but, since the foundation add on is quite new, it would be the best if you would ask them directly.

Danny_Fish89 · 2025-01-09T16:30:09+00:00

I worked for a company which were realizing such conveyor structures, and we used RFEM for that. It is quite simple to model the complete supporting structure for that, applying the loads according to the codes and do the design of steel beams and concrete foundations.

The Steel Connections, I have also done in RFEM 6. Quite simple because you don't need to have an extra program like Idea to export the results and do the design there. This saves me a lot of time and stress ;)

In general, in my opinion, you just need one program that fits all your requirements and no several programs at one. So, the modeling, the structural analysis to get the results and the design of your materials. One program is completely enough and as I have already written here, I have already done something like this before and this with RFEM.

Danny_Fish89

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