Introduction

Question 1

Member that carry loads chiefly in compression. Also known as, compression members.

Answer 1

Columns

Question 2

Two primary types of elements

Answer 2

Flexural Members (Beams) & Compression Members (Columns)

Question 3

Columns maybe subjected to:

Answer 3

1. Axial load without moments (pure compression)
2. Axial load + Bending Moment/s

Question 4

Types of Columns

Answer 4

Tied, Spiral, & Composite

Question 5

A column having ties hold longitudinal bars in place, preventing them to buckle outward under load

Answer 5

Tied Column

Question 6

A column that provide a better seismic applications, more effective but much expensive than tied column

Answer 6

Spiral Column

Question 7

A continuous helical spiral made from nars or heavy wire is wrapped around the longitudinal bars.

Answer 7

Spiral Column

Question 8

Category of Column for which the strength is governed by the strength of the materials and the geometry of the cross section. Also, the preferable category.

Answer 8

Short Column

Question 9

Category of Column for whichmthe strength may be significantly reduced by lateral deflection.

Answer 9

Slender Column

Question 10

As Slenderness Ratios are increased, bending deformations will ____________.

Answer 10

increase

Question 11

The nominal strength Pn of a axially loaded column

Answer 11

Pn = Pcon + Pst
Pn = 0.85 f’c (Ag - Ast) + Ast fy

Question 12

Strength Reduction Factor, Φ of Tied and Spiral Column

Answer 12

Tied, Φ = 0.65
Spiral, Φ = 0.75

Question 13

Reduction Factor to account for accident/bending, α

Answer 13

Tied, α = 0.80
Spiral, α = 0.85

Question 14

Code Requirement for Tied Column

Answer 14

a. Reinforcement Ratio
b. Minimum number of Longitudinal bars
c. Minimum Diameter of Transverse bars
d. Tie Spacing
e. Rectiliniear Ties

Question 15

Code Requirement for Spiral Column

Answer 15

a. Reinforcement Ratio
b. Minimum number of Longitudinal bars
c. Minimum Diameter of Transverse bars
f. Spiral Reinforcement
g. Clear Spacing (Spiral Column)

Question 16

a. Reinforcement Ratio, 𝜌

Answer 16

𝜌 = Ast / Ag
1% ≤ 𝜌 ≤ 8%

Question 17

b. Minimum Number of Longitudinal bars

Answer 17

▪︎ 3 for Traingular Ties
▪︎ 4 for Rectangular Ties
▪︎ 6 for Spiral/ Circular Ties

Question 18

c. Minimum Diameter of Transverse bars

Answer 18

▪︎ min. of 10mm dia for ≤ 32mm dia Longitudinal bars
▪︎ min. of 12mm dia for ≥ 36mm dia Longitudinal bars
▪︎ min. of 12 mm dia for bundled Longitudinal bars

Question 19

d. Tie Spacing (Center-to-Center)

Answer 19

Smax = 16db (db for Longitudinal bars)
Smax = 48db (db for ties)
Smax = least dimension of column

Question 20

e. Rectilinear Ties

Answer 20

(Tied Column only)
▪︎ Spacing > 150 mm
▪︎ Lateral support angle should not be more than 135 degrees

Question 21

f. Spiral Reinforcement

Answer 21

𝜌s = 𝜌min

𝜌s = 4•as / s•Dc
𝜌min = 0.45 ((Ag/Ach) - 1) (f’c/fyt)

Ag = 0.25π (h)²
Ach = 0.25π (Dc)²
as = 0.25π (db-ties)²

Question 22

g. Clear Spacing (Spiral Column)

Answer 22

25mm or dagg < S < 75mm

Question 23

g. Clear Spacing for Spiral

Question 24

The point in the column cross section through which the resultant column load must pass to produce uniform strain at failure.

Answer 24

Plastic Centroid

Question 25

Represent the location of the resuktant force produced by the steel and concrete.

Answer 25

Plastic Centroid

Question 26

In this section, the plastic centroid coincides with the centroid of the column cross section.

Answer 26

Symmetrical sections

Question 27

In this section, the plastic centroid can be located by taking moments.

Answer 27

Unsymmetrical Sections

Question 28

Distance between Column Load and Plastic Centroid of Column.

Answer 28

Eccentricity