Effective Length Factor Calculator

✖Effective Column Length of a column is the length of an equivalent pin-ended column that has the same load-carrying capacity and buckling behaviour as the actual column with different end conditions.ⓘ Effective Column Length [l]			+10% -10%
✖Actual Unbraced Length is the distance between ends of a structural member (such as a column) which are prevented from moving normal to the axis of the member, by bracing, by floor slabs, etc.ⓘ Actual Unbraced Length [l']			+10% -10%

✖Effective Length Factor is the factor used for the members in the frame. It depends on the ratio of compression member stiffness to the end restraint stiffness.ⓘ Effective Length Factor [k]

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Formula

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Effective Length Factor

Formula

`"k" = "l"/"l'"`

Example

`"0.75"="3000mm"/"4000mm"`

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Effective Length Factor Solution

STEP 0: Pre-Calculation Summary

Formula Used

Effective Length Factor = Effective Column Length/Actual Unbraced Length
k = l/l'
This formula uses 3 Variables

Variables Used

Effective Length Factor - Effective Length Factor is the factor used for the members in the frame. It depends on the ratio of compression member stiffness to the end restraint stiffness.
Effective Column Length - (Measured in Meter) - Effective Column Length of a column is the length of an equivalent pin-ended column that has the same load-carrying capacity and buckling behaviour as the actual column with different end conditions.
Actual Unbraced Length - (Measured in Meter) - Actual Unbraced Length is the distance between ends of a structural member (such as a column) which are prevented from moving normal to the axis of the member, by bracing, by floor slabs, etc.

STEP 1: Convert Input(s) to Base Unit

Effective Column Length: 3000 Millimeter --> 3 Meter (Check conversion here)
Actual Unbraced Length: 4000 Millimeter --> 4 Meter (Check conversion here)

STEP 2: Evaluate Formula

Substituting Input Values in Formula

k = l/l' --> 3/4

Evaluating ... ...

k = 0.75

STEP 3: Convert Result to Output's Unit

0.75 --> No Conversion Required

FINAL ANSWER

0.75 <-- Effective Length Factor

(Calculation completed in 00.004 seconds)

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Created by Chandana P Dev

NSS College of Engineering (NSSCE), Palakkad

Chandana P Dev has created this Calculator and 500+ more calculators!

Verified by Ishita Goyal

Meerut Institute of Engineering and Technology (MIET), Meerut

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< 6 Allowable-Stress Design for Building Columns Calculators

Safety Factor for Allowable Compressive Stress

Go Safety Factor = 5/3+((3*((Effective Length Factor*Effective Column Length)/Radius of Gyration))/(8*Factor for Allowable Stress Design))-((((Effective Length Factor*Effective Column Length)/Radius of Gyration)^3)/(8*Factor for Allowable Stress Design^3))

Allowable Compressive Stress when Slenderness Ratio is Less than Cc

Go Allowable Compression Stress = ((1-((((Effective Length Factor*Effective Column Length)/Radius of Gyration)^2)/(2*Factor for Allowable Stress Design^2)))*Yield Stress of Steel)/Safety Factor

Allowable Compressive Stress when Slenderness Ratio is Greater than Cc

Go Allowable Compression Stress = (12*pi^2*Modulus of Elasticity of Steel)/(23*((Effective Length Factor*Effective Column Length)/Radius of Gyration)^2)

Slenderness Ratio Used for Separation

Go Factor for Allowable Stress Design = sqrt((2*(pi^2)*Modulus of Elasticity of Steel)/Yield Stress of Steel)

Factor for Unbraced Segment of any Cross-Section

Go Factor for Allowable Stress Design = 1986.66/sqrt(Yield Stress of Steel)

Effective Length Factor

Go Effective Length Factor = Effective Column Length/Actual Unbraced Length

Effective Length Factor Formula

Effective Length Factor = Effective Column Length/Actual Unbraced Length
k = l/l'

Why is Effective Length Factor used?

The concept of the Effective Length factors of columns has been well-established and widely used by practicing engineers and plays an important role in compression member design. The effective length factor for braced columns varies from 0.5 to 1.0, whereas for unbraced columns, it can vary from 1 to infinity.

Define Radius of Gyration & Slenderness Ratio.

The radius of gyration is defined as the imaginary distance from the centroid at which the area of the cross-section is imagined to be focused on a point to obtain the same moment of inertia. It is the perpendicular distance from point mass to the axis of rotation.
The slenderness ratio can also be defined as the ratio of the effective length of the column to the minimum radius of gyration1. It serves as a measure of the column’s ability to withstand buckling pressure. In structural engineering, slenderness is a measure of the propensity of a column to buckle.

How to Calculate Effective Length Factor?

Effective Length Factor calculator uses Effective Length Factor = Effective Column Length/Actual Unbraced Length to calculate the Effective Length Factor, The Effective Length Factor formula is defined as the ratio of effective length of column to actual unbraced length. Effective Length Factor is denoted by k symbol.

How to calculate Effective Length Factor using this online calculator? To use this online calculator for Effective Length Factor, enter Effective Column Length (l) & Actual Unbraced Length (l') and hit the calculate button. Here is how the Effective Length Factor calculation can be explained with given input values -> 0.75 = 3/4.

FAQ

What is Effective Length Factor?

The Effective Length Factor formula is defined as the ratio of effective length of column to actual unbraced length and is represented as k = l/l' or Effective Length Factor = Effective Column Length/Actual Unbraced Length. Effective Column Length of a column is the length of an equivalent pin-ended column that has the same load-carrying capacity and buckling behaviour as the actual column with different end conditions & Actual Unbraced Length is the distance between ends of a structural member (such as a column) which are prevented from moving normal to the axis of the member, by bracing, by floor slabs, etc.

How to calculate Effective Length Factor?

The Effective Length Factor formula is defined as the ratio of effective length of column to actual unbraced length is calculated using Effective Length Factor = Effective Column Length/Actual Unbraced Length. To calculate Effective Length Factor, you need Effective Column Length (l) & Actual Unbraced Length (l'). With our tool, you need to enter the respective value for Effective Column Length & Actual Unbraced Length and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

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