## Concrete Short Columns - Design Practices

**A short concrete column used in freeway design**

### Short Column Criteria:

To check if a short column is present then the following conditions must be met. Otherwise check to see if you fit under the Concrete Long Column Design type procedure. Ideally, solving for a short column will be easier than a long column.

**If the structure is part of a braced system then:**

{kl_u\over{r}}\le 34-12{M_1\over{M_2}}\le 40

**If the structure is part of a unbraced system then:**

{kl_u\over{r}}\le 22

*where:*

k = the effective length factor (can be conservatively taken as 1.0

l

M

M

r = radius of gyration

^{[1]})l

_{u}= clear height of the columnM

_{1}= the smaller absolute value of the two end moments acting on the columnM

_{2}= the larger absolute value of the two end moments acting on the columnr = radius of gyration

### Concrete Short Column Analysis

Several methods for concrete short column design have been provided below including:

- Concrete Tied Columns
- Concrete Spiral Columns
- Concrete Column Design for Small Eccentricity
- Concrete Column Design for Large Eccentricity
- Concrete Column Interaction Diagrams

### References:

- American Concrete Institute, "Building Code Requirements for Structural Concrete (ACI 318-05) and Commentary (ACI 318R-05)", 2005
- From Section 10.12.2