ENGINEERING – TRUCTURAL ENGINEERING β TEEL CALCULATOR
Moment Frame Drift
A precise tool.
What is the Moment Frame Drift & How does it work?
In a momentβframe building the lateral stiffness is primarily provided by the bending resistance of the column sections. When a horizontal load is applied, each story behaves similarly to a cantilever beam fixed at the base, and the resulting lateral drift can be estimated using elementary beam theory.
The cantilever method assumes that the frameβs shear deformation is negligible compared with flexural deformation, which is a reasonable approximation for steel moment frames with relatively stiff connections. By treating each story as an independent cantilever, the drift is directly related to the applied shear force, the story height, and the flexural rigidity of the column.
Using the classic beamβdeflection formula, the story drift (Ξ) is expressed as a function of the lateral load (P), story height (h), modulus of elasticity (E), and moment of inertia (I). This relationship provides a quick check for serviceability limits before detailed finiteβelement analysis.
\Delta = \frac{P ; h^{3}}{3 ; E ; I}
\Delta = lateral drift (in)
Parameters
Result
β
Frequently Asked Questions
What is the purpose of the Moment Frame Drift Calculator?
The calculator estimates the lateral drift in moment frame buildings by treating each story as a cantilever beam, assuming negligible shear deformation.
When is the cantilever method applicable for moment frames?
The cantilever method is applicable for steel moment frames with relatively stiff columns where shear deformation is much smaller than flexural deformation.
How does horizontal load affect a moment frame building?
A horizontal load causes each story of a moment frame building to behave like a cantilever beam, resulting in lateral drift that can be estimated using beam theory.
What factors are considered when calculating moment frame drift?
Factors include the stiffness of the columns, the height of the building, and the magnitude of the applied horizontal load.
Can this calculator be used for non-steel moment frames?
While primarily designed for steel moment frames, the principles can be adapted for other materials with similar properties and assumptions.
What is lateral drift in a building structure?
Lateral drift refers to the horizontal displacement of a building’s stories due to external forces like wind or earthquakes.
Why is shear deformation neglected in this calculation?
Shear deformation is neglected because it is typically much smaller than flexural deformation in stiff steel moment frames, making beam theory a reasonable approximation.
Results are for informational purposes only and do not constitute professional advice.