Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams Solution

STEP 0: Pre-Calculation Summary
Formula Used
Laterally Unbraced Length for Plastic Analysis = (Radius of Gyration about Minor Axis*(5000+3000*(Smaller Moments of Unbraced Beam/Plastic Moment)))/Yield Stress of Steel
Lpd = (ry*(5000+3000*(M1/Mp)))/Fy
This formula uses 5 Variables
Variables Used
Laterally Unbraced Length for Plastic Analysis - (Measured in Meter) - Laterally Unbraced Length for Plastic Analysis is the distance between two ends of a member which is prevented from movement and contain plastic hinges.
Radius of Gyration about Minor Axis - (Measured in Meter) - Radius of Gyration about Minor Axis is the root mean square distance of the object's parts from either its center of mass or a given minor axis, depending on the relevant application.
Smaller Moments of Unbraced Beam - (Measured in Newton Meter) - Smaller Moments of Unbraced Beam is the smallest moment in the ends of beams which is unbraced.
Plastic Moment - (Measured in Newton Meter) - Plastic Moment is the moment at which the entire cross section has reached its yield stress.
Yield Stress of Steel - (Measured in Megapascal) - Yield Stress of Steel is the stress at which the material begins to deform plastically, meaning it will not return to its original shape when the applied force is removed.
STEP 1: Convert Input(s) to Base Unit
Radius of Gyration about Minor Axis: 20 Millimeter --> 0.02 Meter (Check conversion ​here)
Smaller Moments of Unbraced Beam: 100 Newton Millimeter --> 0.1 Newton Meter (Check conversion ​here)
Plastic Moment: 1000 Newton Millimeter --> 1 Newton Meter (Check conversion ​here)
Yield Stress of Steel: 250 Megapascal --> 250 Megapascal No Conversion Required
STEP 2: Evaluate Formula
Substituting Input Values in Formula
Lpd = (ry*(5000+3000*(M1/Mp)))/Fy --> (0.02*(5000+3000*(0.1/1)))/250
Evaluating ... ...
Lpd = 0.424
STEP 3: Convert Result to Output's Unit
0.424 Meter -->424 Millimeter (Check conversion ​here)
FINAL ANSWER
424 Millimeter <-- Laterally Unbraced Length for Plastic Analysis
(Calculation completed in 00.020 seconds)

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Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams
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Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams Formula

​LaTeX ​Go
Laterally Unbraced Length for Plastic Analysis = (Radius of Gyration about Minor Axis*(5000+3000*(Smaller Moments of Unbraced Beam/Plastic Moment)))/Yield Stress of Steel
Lpd = (ry*(5000+3000*(M1/Mp)))/Fy

What is a Plastic Hinge?

In the structural engineering beam theory, the term "Plastic Hinge" is used to describe the deformation of a section of a beam where plastic bending occurs. By inserting a plastic hinge at a plastic limit load into a statically determinate beam, a kinematic mechanism permitting an unbounded displacement of the system can be formed. It is known as the collapse mechanism.

How to Calculate Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams?

Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams calculator uses Laterally Unbraced Length for Plastic Analysis = (Radius of Gyration about Minor Axis*(5000+3000*(Smaller Moments of Unbraced Beam/Plastic Moment)))/Yield Stress of Steel to calculate the Laterally Unbraced Length for Plastic Analysis, The Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams formula is defined as the limiting lateral unbraced length of beams which are boxed in shape and of solid bars when plastic hinges are present. Laterally Unbraced Length for Plastic Analysis is denoted by Lpd symbol.

How to calculate Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams using this online calculator? To use this online calculator for Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams, enter Radius of Gyration about Minor Axis (ry), Smaller Moments of Unbraced Beam (M1), Plastic Moment (Mp) & Yield Stress of Steel (Fy) and hit the calculate button. Here is how the Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams calculation can be explained with given input values -> 424000 = (0.02*(5000+3000*(0.1/1)))/250000000.

FAQ

What is Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams?
The Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams formula is defined as the limiting lateral unbraced length of beams which are boxed in shape and of solid bars when plastic hinges are present and is represented as Lpd = (ry*(5000+3000*(M1/Mp)))/Fy or Laterally Unbraced Length for Plastic Analysis = (Radius of Gyration about Minor Axis*(5000+3000*(Smaller Moments of Unbraced Beam/Plastic Moment)))/Yield Stress of Steel. Radius of Gyration about Minor Axis is the root mean square distance of the object's parts from either its center of mass or a given minor axis, depending on the relevant application, Smaller Moments of Unbraced Beam is the smallest moment in the ends of beams which is unbraced, Plastic Moment is the moment at which the entire cross section has reached its yield stress & Yield Stress of Steel is the stress at which the material begins to deform plastically, meaning it will not return to its original shape when the applied force is removed.
How to calculate Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams?
The Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams formula is defined as the limiting lateral unbraced length of beams which are boxed in shape and of solid bars when plastic hinges are present is calculated using Laterally Unbraced Length for Plastic Analysis = (Radius of Gyration about Minor Axis*(5000+3000*(Smaller Moments of Unbraced Beam/Plastic Moment)))/Yield Stress of Steel. To calculate Maximum Laterally Unbraced Length for Plastic Analysis in Solid Bars and Box Beams, you need Radius of Gyration about Minor Axis (ry), Smaller Moments of Unbraced Beam (M1), Plastic Moment (Mp) & Yield Stress of Steel (Fy). With our tool, you need to enter the respective value for Radius of Gyration about Minor Axis, Smaller Moments of Unbraced Beam, Plastic Moment & Yield Stress of Steel and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.
How many ways are there to calculate Laterally Unbraced Length for Plastic Analysis?
In this formula, Laterally Unbraced Length for Plastic Analysis uses Radius of Gyration about Minor Axis, Smaller Moments of Unbraced Beam, Plastic Moment & Yield Stress of Steel. We can use 1 other way(s) to calculate the same, which is/are as follows -
  • Laterally Unbraced Length for Plastic Analysis = Radius of Gyration about Minor Axis*(3600+2200*(Smaller Moments of Unbraced Beam/Plastic Moment))/(Minimum Yield Stress of Compression Flange)
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