Analysis and Design of Slabs Contents

Slab Analysis and Design Procedure

Solid Slabs and Flat Slabs can be analysed and designed in ProtaStructure.  

General Procedure

1. Before designing the slabs, review the Slab Design Settings.
2. Slab reinforcements can be drawn automatically using  “ Slab Strips ” function the modelling tab, cutting through slabs to be analysed and designed. Suitable Slab Strip type must be defined so that the slabs can be analyzed with an appropriate method : 
  1. The “Analytical Strip” type employs the Moment Coefficient Method. The reinforcements will be drawn on the screen automatically.
  2. The “FE (Finite Element) Strip” type is used in conjunction with the results of an FE floor analysis which must be performed. Following, each slab strip should be updated by using “Update Steel Bars” as explained in following section.
  3. The “Manual Strip” type can be specified where reinforcement is to be placed directly without any design, i.e. the reinforcement manually entered. 
3. Go to Design Tab > choose " Slab Analysis & Design" to generate the report.
The ultimate load factors used in the slab analysis are obtained from the first load combination defined in the Standard Load Combination used in the analysis of the building. Therefore, when a customized load combination is used, special care must be taken to have the first combination to reflect the correct load factors.

Select Rebars Manually

User can manually adjust and select the rebars by right click on the rebars drawn > properties > adjust on Quantity, Diameter and/or Spacing. 

Arrange Steel Bars 

After drawing the appropriate slab strips, the slab rebars can be updated or deleted :
1.  Select one or multiple select slab strip on the plan view (by holding down CTRL key)
2. If no slab strip is selected, then it is assumed all slab strips are selected. 
3. Right click anywhere on the plan view > Choose " Arrange All Steel Bars" which will expose 2 options :  

1. Update Steel Bars

The “Update Steel Bars” option can be used for drawing steel bars of a slab for the first time or to update the steel bars already drawn. It basically act as "Delete and Re-select All Rebars".
If the steel bars required for a slab have changed as a result of a new analysis, then the “Update Steel Bars” option will update reinforcements drawn including the manually assigned rebars design based on the previous analysis.
If you increased some of the reinforcements manually then these bars will be changed by the updating procedure.

2. Delete Steel Bars

The “Delete Steel Bars” option erases all the steel bars drawn on the screen.

For Flat Slab analysis & design, please refer to this article :  Working with Flat Slabs
You may find it helpful to watch this video : Slab Design Options in ProtaStructure

Limitation of Slab Design

Slab design will not automatically design for deflection which is similar to beam design, it's checking for deflection only. User will be require to adjust the rebars  manually to pass the deflection check.




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