What is Online Frame Analysis?

Frame analysis is a fundamental process in structural engineering used to determine how a structure behaves under various loads. It involves calculating internal forces, such as bending moments, shear forces, and axial forces, as well as support reactions and displacements. This Frame Analysis Calculator Online is specifically designed to provide quick results for portal frames, which are widely used in industrial sheds, warehouses, and commercial buildings.

How to Use This Frame Calculator

To use this tool effectively, follow these simple steps:

• Enter Dimensions: Input the span length (horizontal distance between columns) and the height of the columns.
• Select Loading: Choose between a Uniformly Distributed Load (UDL) across the beam or a Point Load at the center.
• Define Stiffness: The ratio of the moment of inertia of the beam to the column significantly affects moment distribution. A ratio of 1 assumes equal member sizes.
• Support Conditions: Choose between Pinned (free to rotate) or Fixed (restrains rotation) bases.

Understanding the Results

The tool provides the horizontal thrust (H), which is the inward force pushing against the base supports, and the vertical reactions. For fixed frames, it also calculates the bending moments at the corners and the maximum span moment. These values are essential for sizing steel sections or designing reinforced concrete members. Using an online structural analysis tool speeds up the preliminary design phase, allowing engineers to iterate through different configurations quickly before moving to complex finite element analysis (FEA) software.

Frequently Asked Questions

Q: What is a Portal Frame?
A: A portal frame is a simple structure comprising columns and a horizontal or pitched rafter, connected by moment-resisting joints. It is highly efficient for creating large open spans.

Q: Why does the horizontal thrust change with stiffness?
A: In indeterminate structures, the distribution of forces depends on the relative stiffness of the members. A stiffer beam will attract more moment and change the horizontal reaction at the base.