So, let’s talk about Preliminary Design. It is done through a utility called The Wizard. The Wizard can generate automatically the reinforcing layout for the entire structure. This reinforcing is explicitly defined:  number of rebars, size, length, location and spacing.

Let’s have a look. Here is the Wizard menu.

First, you can give yourself the benefit of a little extra Safety Factor. Considering that the Wizard provides you with actual reinforcing (not just minimum areas) a little leeway here, may get you out of trouble later. Next you assign your preferences for longitudinal and transverse reinforcing: cover, preferred diameters, preferred splice locations, etc. Beams, columns and walls are treated separately. 

With beams you have the option of forcing a small increase in the bottom reinforcing. This can be sweet if you want to provide for some moment redistribution. A more refined Moment Redistribution procedure, based on Eurocode provisions, is also available, as explained in a separate video.

Now that everything is set, let’s run the Wizard. 

Reinforcing is designed based on Strength and Detailing Provisions. If the seismic setting is active, Capacity Design is also imposed.  Note that the Wizard does not account for service conditions. These can be addressed directly in the editing phase.

The calculation algorithm automatically identifies continuity conditions along column lines or beam spans. The reinforcing is designed to remain continuous through supports, where possible. Not always the Wizard can reach a solution good for all load combinations and design requirements. At some locations, because of the many constraints, particularly the size of concrete sections, there could not be a solution.

To identify these emergencies, after the Wizard is done you should run design checks for all members and design areas of concern. If required, edit the model as necessary.

Done! This is what the results look like.

Note that columns are always designed with evenly spaced rebars. While correct, this reinforcing could be excessive when columns are in single bending. Again, you have the option to refine this reinforcing during the editing phase.

It should be noted that there is an infinite number of solutions where the reinforcing layout will satisfy code requirements. The choice of reinforcement is very personal. The solution proposed here is just one among many: by no means the best. Going through the subsequent editing phase is fundamental.

This is it. Thank you, for your attention. To the next Video!