Columns

The second structural element is column (compression member) ,this element which provide construction elevation and connects the footing with beams and slabs to transfer the loads .

types of columns according to braces :

1-braced column; this system prevent the side sway because of connection columns with beams , most of braced columns is made from steel , and this is one of it's good features and the other one is to carry lateral load like wind load and seismic load.

2-unbraced column; this types of column didn't prevent side sway and can't carry any of lateral loads .

types of columns according to column cross sectional shape :

1-Circular columns 

2-Rectangular columns

3-Square columns 

4-Hexagonal columns

types of columns according to column's length :

1-long columns : when the ratio of length to least cross sectional dimension is more than 12
2-short columns : when the ratio of length to least cross sectional dimensions is less than 12 and more than 3 

Buckling in columns 

The short columns will fail in compression before it reach buckling , but the long columns will fail firstly in buckling and this depends on many factors :

1-length of columns

2-cross section dimensions 

3-the fixity of column's end

4-slenderness ratio

ties in columns :

types of ties in columns :

1-rectangular ties

2-spiral tieds

we use ties in columns to :

1- bind and hold longitudinal bars .

2-prevent concrete from splitting outwards

3-resisting horizontal force (shear )

4-spiral ties are carrying 10% of the axial load on the column .

       columns reinforcement