How do we determine column cross-sections?

P

Paul George

New Member
Hello, first of all. As someone who is just learning the profession, do we find the cross-section dimensions of the columns by hand one by one or by trial and error based on experience? Can we use other programs such as excel or other programs for this?
 
We call it experience, engineering intuition, or acquired talent. No auxiliary account is required. Choose yourself a minimum size (eg 30/40 - 30/50 ) Then you can do trial and error.
 
Thank you. For example, we determined the column as 30/50. Should we put the 30 cm we determined (taking into account all the columns in the building, since the column is not square) in the x direction or y direction? How can we calculate for this, taking into account the symmetry? How can we adjust all the columns in this way? is this also experience or not :D
 
You need to pay attention to the center of stiffness in the direction. It should be close even if it does not overlap the center of gravity. This is achieved by changing the faces of the non-symmetrical columns in the -x and -y directions. For example, in an axis using 30/50 columns, the 30 cm-long side should not always face the -x direction or always face the -y direction. If we cannot touch that axis due to architectural restrictions, we should apply this to other axis. When you do this, you will see that the center of rigidity and the center of gravity approach each other. Center of Rigidity: It is the resultant of shear forces such as wind and earthquake coming into the structure. I wish you good work.
 
You can follow a path like this until you have experience. Build your carrier system. Calculate the approximate vertical loads on the columns. Use 1.4 G+1.6 Q loading for vertical load calculation. Then, from the maximum vertical load formulation in Ts500 and Earthquake regulations, min. Calculate the column cross-sectional area.
 
It is useful to keep your Tx and Ty periods close to each other. In general, and approximately for each floor, the period is increased by 0.1s. That is, for a 5-storey building, Period = 0.5-0.6sec is good. You can arrange your carrier system, column sections and directions to capture these values. Consider a 5-storey building. Let the Tx period be 0.54sec and Ty=0.8sec. Here, while Tx is normal, Ty is too much. In such cases, you increase the stiffness in the Y direction and decrease the period to 0.5-0.6sec.
 
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