1. If using an American code for code check, is there any parameter to define the material factor or is it already included?
2. I am performing concrete design for a beam per the ACI code and I encounter an error message : "LOCATION FOR DESIGN FOR SHEAR AT START OF MEMBER 2 IS BEYOND THE MIDPOINT OF MEMBER. DESIGN FOR SHEAR AND TORSION NOT PERFORMED." How can I get around this situation?
3. I am doing a footing design in STAAD.Pro 2002. I am unfamiliar with the term "dowel reinforcement". I am guessing that this is a term used by American engineers. Could you explain what that is?
4. My input file contains 2 load cases - case 1 and 2. For member 43, case 2 produces a larger value of shear force along local Y axis than case 1. However, the concrete design report indicates case 1 as being critical for shear design, and not case 2. How do you explain this?
5. Why is it that the concrete column interaction diagram is not plotted in the output although track 2 was specified?
6. I am performing concrete design for a beam per the ACI code. At the start as well as the end nodes of the member, the value "Vu" which is reported in the shear design output does not match the shear force Fy from the member end force output. Why is that?
7. When I perform concrete design on an element, the output contains expressions such as "LONG. REINF.", "TRANS. REINF.", "TOP", "BOTT.", etc. Can you explain what these terms mean?
8. When I perform concrete design on an element, the output reports reinforcement in terms of "SQ.MM/MM". Can you please explain why?
9. A floor slab has been modeled using 4-noded plate elements. The elements are subjected to pressure loading in the vertically downward direction. A concrete design has been performed on the elements. (See below for the reinforcement report for many of those elements.) Why is it that the moments as well as reinforcement are appearing on the top and not on the bottom of the plates?
10. For an existing concrete member, I need to compute the capacity of the section. How do I do this?
11. Can I change the strength reduction factors in the program? For example: For a tied concrete column, I assume that the current value is 0.70. Can it be changed to 0.65?
12. In concrete design per the ACI code, if the size of the concrete beam member which I am designing is limited and I need to have 2 rows of reinforcement in the top or the bottom of the beam, how do I input this request? Or Does Staad automatically output the data with the second row? have been trying to find this in the Manuals. I have seen LEVELS BUT IT DOES NOT SAY WHAT I NEED.
13. In concrete design per the ACI code, what does the following expression in the STAAD output file mean: BAR SIZE CAN NOT BE MATCHED TO MEET ALL REQUIREMENTS
14. How do I interpret the element design results per the ACI code
15. As part of the concrete column design output STAAD.Pro plots the Pn and Mn. Does Staad convert the Nominal Strength to Design Strength in order to check the column? Does it design for axial load plus biaxial bending ? How is the phi factor ascertained ?
16. I am trying to define a Slab Design brief from within the RC Designer ( Concrete Design mode ). The Main Reinforcement tab refers to directions like X and Y. How do I know which directions are these referring to and can I change it ? Also what does the terms “Top/Bottom” and “Outer” bars represent ?
17. I am designing a concrete column in STAAD.Pro but STAAD is only designing for the first load case in spite of the fact that the other cases have higher forces.

16. I am trying to define a Slab Design brief from within the RC Designer ( Concrete Design mode ). The Main Reinforcement tab refers to directions like X and Y. How do I know which directions are these referring to and can I change it ? Also what does the terms “Top/Bottom” and “Outer” bars represent ?

As far as X and Y direction are concerned, these are displayed on the slab itself when you go to the Concrete slab > Summary page within RC Designer. You can always change the direction of X and Y, if you want to, by going to the menu option Slab > Slab Axes. The resulting dialog box would provide option to define the X direction either by selecting two existing slab nodes or by selecting a component plate, in which case the X is aligned along the local X of the selected plate. Once you make the change, the graphics may not refresh. To refresh it, right click on the graphics window, choose Diagrams > General > uncheck the box for Design Axis> click Apply which should remove the axis plot. Now recheck the Design axis check box and click Apply. You will now see the modified orientation of X and Y. Outer bar simply denotes the bars which are closest to the top and bottom faces of the slab. Once the X and Y are established, you can use the right hand rule to find positive Z. The face in the direction of the positive Z would be the top face of the slab just like in STAAD.Pro. The opposite face would be considered the bottom face.

So if you have Outer bar direction set to “X” under Top Bar Criteria, it means that for the top face of the slab, the bars which are placed nearest to the face, are oriented along the X direction. The bars in Y would be inside the X direction bars.

17. I am designing a concrete column in STAAD.Pro but STAAD is only designing for the first load case in spite of the fact that the other cases have higher forces.

STAAD.pro designs the columns for all load cases. The reporting of critical case is not based on the highest member forces but is rather based on the highest reinforcement requirement. The load case that requires the Maximum Reinforcement is reported as the critical case.

Now , if it so happens that the reinforcement requirement is minimum for all the load cases, then only the first load case in the load list gets reported as the worst case. The reason being, no other load case that follows the first load case, requires higher reinforcement than what is required by the first load case in the list. The output should also contain a statement that "Only Minimum Steel Is required". 

To verify this, use separate load list & column design commands for a few load cases which you feel may be critical & check the reinforcement. You will find that the reinforcement requirements for all of these subsequent load cases are either the same as that required for the first load case (301 shown in the above figure) or are lesser than that required for the first load case.

See Also

Product TechNotes and FAQs

Structural Product TechNotes And FAQs

External Links

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