Structural design of a concrete wall (EN)
1 New project
Start a New project in IDEA StatiCa Detail.
Select the topology of the discontinuity region – Wall with window and door openings.
Start the definition of Geometry. Six items have been already created by the template: wall W1, two openings O1 and O2, and three line supports LS1-3.
Shift the opening O2 rightwards by reducing its X-position from point 2.
In this example, you will work with a prefabricated wall supported by two linear supports. You can easily delete the third support LS3 by clicking on it in the list or by clicking on the middle support in the Main window and then click on the delete icon. Both ways are always possible.
The geometry of the wall looks like this, now:
3 Load effects
Now, move to define the Load on the wall. You can see, that two load cases and three combinations were already created. Change the content of the load cases a little bit.
The load case LC1 (permanent) contains two line loads in Load impulses: uniform vertical load LL1 on the top edge 3 and linear horizontal load LL2 on the left edge 4. Keep these values as default.
In Load impulses of LC2 (variable load case), delete the load case LC4.
In LL3, reduce the value of the uniform line load to -15 kN/m.
Three nonlinear combinations were already defined: C1 stands for ULS checks. C2 is a quasi-permanent and C3 a characteristic load combination, both defined for SLS code checks (see the tab Load cases & Combinations). The partial coefficients for the combination rules can be adjusted as well.
As you do not need to evaluate the individual load cases, they are unchecked which implies that they will not be analyzed. The calculations will be performed only for the checked items (combinations C1, C2 and C3).
Once the load has been defined, you can proceed to define the reinforcement.
Let the Design tools display the regions with tension/compression.
First, run the Linear Analysis (assumptions explained in the Theoretical background).
To see the most compressed fields better, you can set the filter for Compression on -1.0 MPa in the top ribbon.
Alternatively, you can use a more advanced Topology Optimization tool to see how the most effective reinforcement layout should look like if you want to use a selected effective volume of the member.
For the effective volume of 40%, the structure looks like this (again, red lines represent compression and blue lines represent tension):
Let´s switch to Input/Edit of reinforcement layout. The results from design tools will remain in the background with lighter colors to see if your reinforcement complies with tensioned fields. If you do not want to display them, just easily click on the Design tool icon and it will be switched off.
You will exploit the 6 predefined items created by the template.
As you see from the results of the topology optimization, the governing rebar will be the inclined one. Its length is insufficient due to the tensile area developed from the door opening to the bottom edge of the window opening.
To elongate this inclined bar, click on it in the scene and it will be chosen from the list of reinforcement items, or click on IB1 operation in the list. Modify the angle of the rebar and edit the top length. The small orange arrow in the scene points to the top direction of the selected bar.
You will also extend GB2 to the top edge of the wall.
You can display the Real 3D view on the top ribbon if you switch off the Design tools buttons. This is the 3D representation of the reinforcement.
5 Calculation and Check
Proceed to calculate the project. Continue to Check in the navigator and press the Calculate button at the top ribbon. The analysis model is automatically generated, calculations are performed and you can check the results.
In the data window at the bottom, all detailed results can be found. Now the strength check of the concrete in ULS combination (C1) is presented.
You can notice the portion of applied permanent and variable load (P100%, V100%.) In the top ribbon, the limit value for the diagram can be changed. Change the value so that only the concrete in compression over -1 MPa is marked red.
By changing the top tabs, you can display all the code checks. In the Summary, the main results for ULS/SLS are presented. Click on the line in ULS/Strength of reinforcement to display the utilization of the rebars (with the most critical spot marked in the figure).
Open the SLS results by selecting, e.g., the line SLS/Stress limitation line in the table.
To go through the detailed checks of each component, start with click on the Strength tab. This will open concrete ULS checks such as utilization in stress, stresses in principal direction, strains, and also a map of reduction factor kc. As noted above in the table, the C1 combination was used to check ULS.
If you want to see such results for reinforcement, you need to click on the row with the Reinforcement title. This will change the ribbon options and also will unroll the table for results. You can display results for strains and stresses in each bar and their utilization.
In the Anchorage tab, you can show the results for the bond model and anchorage of bars. This includes anchorage forces, total forces diagrams along the rebars, bond, and slip. You can see the Total force that is carried through the selected group bars.
The results of SLS checks can be found in the Stress, Crack, and Deflection tab. For the Stress limitation state, the C2 combination was governing to check the concrete, while C3 to check the reinforcement.
Calculated crack widths can be displayed in the Crack tab (combination C2). The calculated values are compared to the limit value wlim.
You can also look at the Deformed shape of the wall (top ribbon within the Deflection tab).
At last, go to the Report Preview/Print. IDEA StatiCa offers a fully customizable report to print out or save in an editable format.
You have designed, optimized, and code-checked the wall with the openings.