IDEA StatiCa tutorial – Wall

In this tutorial, we will go step by step in modeling and code check of concrete wall with two openings.

1 New project

We start a New project in IDEA StatiCa Detail.

In the Discontinuity Region Wizard, we set the concrete and reinforcement grade and we define the Concrete cover thickness. We select the Wall template.

 

We select the topology of the discontinuity region – Wall with window and door openings.

 

2 Geometry

We start the definition of the Geometry. Six items have been already created by the template: wall W1, two openings O1 and O2, and three line supports LS1-3.

We shift the opening O2 rightwards by reducing its X-position from point 2.

 

In this example, we will work with a prefabricated wall supported by two linear supports. We can easily delete the third support LS3 by clicking on it in a list or by clicking on a middle support in Main window and then click on delete icon. Both ways are always possible.

 

The geometry of the wall looks like this, now:

 

3 Load effects

Now, we move to define the Load on the wall. We can see, that two load cases and three combinations were already created. We 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. We will keep these values as default.

 

In Load impulses of LC2 (variable load case), we delete the load case LC4.

 

In LL3, we 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 we 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).

 

4 Reinforcement

 

Once the load has been defined, we can proceed to define the reinforcement.

We let the Design tools display the regions with tension/compression.

Linear analysis

First, we run the Linear Analysis.

To see the most compressed fields better, we can set the filter for Compression on -1.0 MPa in the top ribbon.

 

Topology optimization

Alternatively, we can use more advanced Topology Optimization tool to see how the most effective reinforcement layout should look like if we want to use 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 background with lighter colors to see if our reinforcement complies with tensioned fields. If we do not want to display them, just easily click on Design tool icon and it will be switched off.

 

We will exploit the 6 predefined items created by the template.

As we 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 door opening to bottom edge of window opening.

 

To elongate this inclined bar, click on it in scene and it will be chosen from list of reinforcement items or click on IB1 operation in the list. We modify the angle of rebar and edit top length. The small orange arrow in the scene points the top direction of the selected bar.

 

We will also extend GB2 to the top edge of the wall.

 

We can display the Real 3D view in the top ribbon if we switch off the Design tools buttons. This is the 3D representation of the reinforcement.

 

5 Calculation and Check

We proceed to calculate the project. We continue to Check in the navigator and press the Check button it the top ribbon. Analysis model is automatically generated, calculations are performed and we can check 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. We change the value so that only the concrete in compression over -1 MPa is marked red.

 

By changing the top tabs, we can display all the code checks. In the Summary, the main results for ULS/SLS are presented. We 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).

 

We 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, we start with click on Strength tab. This will open concrete ULS checks such as utilization in stress, stresses in principal direction, strains and also map of reduction factor kc. As noted above the table, C1 combination was used to check ULS.

 

If we want to see such results for reinforcement, we need to click on a row with Reinforcement title. This will change the ribbon options and also will unroll the table for results. We can display results for strains and stresses in each bar and their utilization.

 

In the Anchorage tab, we can show the results for bond model and anchorage of bars. This includes anchorage forces, total forces diagrams along the rebars, bond, and slip. We can see a Total force which is carried through the selected group bars.

 

The results of SLS checks can be found in Stress, Crack and Deflection tab. For the Stress limitation state, C2 combination was governing to check the concrete, while C3 to check the reinforcement.

 

Calculated crack widths can be displayed in Crack tab (combination C2). The calculated values are compared to the limit value wlim.

 

We can also look at the Deformed shape of the wall (top ribbon within the Deflection tab).

 

6 Report

At last, we go to the Report Preview/Print. IDEA StatiCa offers a fully customizable report to print out or save in editable format.

 

 

We have designed, optimized and code-checked the wall with the openings.

 

Keywords:

concrete, wall, wall with window opening, wall with door opening, prefab wall, load, load combinations, ULS, SLS, design, reinforcement, topology optimization, code-check, Eurocode, limit state, CSFM, stress field, non-linear analysis, load increment, concrete softening, tension stiffening, strength, anchorage, stress limitation, creep, crack width, deflection

 

Related articles and tutorials:

How to design and code-check prefab wall

Sample projects

A solution for walls and details of concrete structures