Structural design of a concrete corbel (EN)
1 New project
Launch IDEA StatiCa and select the application Detail.
Create a new project by clicking New. The Wizard window is opened, and you can start with a selection of proper concrete grade and cover. Then continue with Frame joints in Templates.
Then choose the template Column with bracket.
Change the cross-section of the column:
Change the Length of the left beam to 0.85 m.
After that, you can move the bearing plate BP1 to the center. To achieve that, change its X-position to 0.25 m.
Geometry has been finished, and you can move on to the Loads.
Two load cases and three combinations were automatically added. In order to be able to distinguish between short-term and long-term effects, it is necessary to set correctly permanent and variable load cases. The settings greatly impact the interpretation of ULS and SLS checks.
Modify the automatically added load case LC1 for permanent effects. In the Load impulses tab, you can see a point load applied on the bearing plate.
Change its value to -120 kN.
Now you need to adjust the internal forces according to the modified external load.
In general, you have to reach equilibrium at the intersection of the column and the corbel. This trimmed part of the structure does not know about the internal forces and the behavior of the rest of the model, so you input them manually. The convention of internal forces is displayed in the Data window.
Notice the change displayed in the main window on the right side. Here you can check if our internal forces correspond with the internal forces from the global analysis.
Switch back to Load impulses to modify the variable load case LC2 by changing the value of the vertical point load to -200 kN.
Add a new horizontal point load by clicking on the Plus button. The horizontal force should be in global X-direction and its value will be -40 kN.
Switch again to Internal forces and input the following:
You achieved the equilibrium, and the internal forces are corresponding with the global analysis, so you can move on to define the Combinations.
Go back to the tab Load cases & Combinations and choose combination C1. If you click on the pen icon, you can modify the combination rules.
The combination C1 has been already set as ULS combination, C2 as Quasi-permanent SLS combination, and C3 as Characteristic SLS combination. The partial factors should be set according to the table below:
Notice the unticked checkboxes for load cases. The calculations will be performed just for the ticked items, and by excluding load cases, you will speed up the calculation. Set the checks for the three combinations only.
The loads and combinations are all set, the next step is the design of reinforcement.
The next step is to reinforce the model. We will edit the reinforcement in the template, but at first, we look at the Topology Optimization in Design tools. The calculation uses an effective volume of the member (for example 40% in our case) and places this volume in the most effective way, so the created structure is the stiffest possible.
Red areas represent compression fields and blue areas are in tension. If you want to reinforce our detail based on these results, you can switch to Input/Edit.
Two stirrup groups and four groups of bars were already added by the template, you will only adjust them to your needs.
In the group GB3, change the number of layers to 5, their distance to 120 mm, and the diameter of bars to 8 mm.
Then change the diameter of GB4 to 20 mm and the number of bars in layer to 3:
You can check out the alignment of reinforcement using the Real 3D view.
Reinforcement is done, you can proceed to Checks.
5 Calculation and Check
Start the analysis by clicking on the Calculate button in the ribbon.
The analysis model is automatically generated, the calculations are performed and you can see the Summary of checks displayed together with the values of check results.
To go through the detailed checks of each component, start with the Strength tab. This will show concrete checks such as utilization in stress, the direction of principal stresses, strains, and also a map of reduction factor kc, which can be switched on the ribbon.
For detailed results of reinforcement, you need to click on the row Reinforcement. This will change the ribbon icons and also will unroll the table for results. You can display results for strains and stresses in each bar and their utilization.
All results can be displayed in the same way. Show the settings in the ribbon for SLS checks of Crack and Deflection. Besides the icons to switch between the results, there are settings in the ribbon to specify the limit value or display of results from short/long-term effects. Short-term effects are calculated considering elastic modulus Ecm. Long-term effects take into account the effect of creep of concrete, so we calculate with the effective elastic modulus Ec,eff.
6 Bill of material
Now, go to the Bill of material. You can export it to DXF and further edit – all the reinforcement is exported into blocks that can be exploded to polylines.
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 a corbel according to Eurocode.