ORION 18: HOW TO MODEL, ANALYSE AND DESIGN A WAFFLE SLAB

For this tutorial, we are going to modify part of the model created in the 'LearningOrion' tutorial we have been using. We will remove slab '1S2' on the first suspended floor and replace it with a waffle slab. Let's start by revisiting our model.

Split view of the 'LearningOrion' tutorial model

Step 1

We go to 'Storey:St01', and select slab '1S2', then delete it.

NB: To easily select slabs, click on the dimension tag titled '1S2' as seen below for the main reinforcement bars.

Step 2

Next, click on the 'Ribbed Slab' signin the menu toolbar near the top of the screen.

In the 'Ribbed Slab Properties' dialog box that appears, Go to 'Type'. click the dropdown and select 'Grillage'.

The meaning of the different parameters 'bw', 'h', 'h-Slab' and 's-Block' are as shown below

'h' is the total height of the waffle beams

'h-Slab' is the height of the slab

'bw' is the width of the waffle

's-Block' is the distance between the waffles

Step 3

Click in the area where slab '1S2' so as to create the slab as shown below

Step 4

Next, we analyse the waffle slab. To do that, we run slab strips perpendicular to the ribs. Click 'Run', then 'Ribbed Slab Analysis' in the menu toolbar. Check the box for 'All Storeys' in the 'Ribbed Slab Analysis' dialog box, then click 'Design'.

Step 5

Now we design the waffle slab. To do so, Click 'Run' - 'Beam Section Design and Detailing' - 'Rib' to open the 'Rib Section Design and Detailing' dialog box and complete the design as was done for beam design

*Waffle slab image courtesy of IMCP

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