What is Sub-frame Analysis and Continuous Beam Analysis?

Introduction #

There are two methods used in structural engineering to analyze the behavior of a structure, particularly how the vertical or gravity loads are carried by the members of the structure. 

• Sub-frame analysis
• Continuous beam analysis

Sub-frame Analysis #

This method is done by dividing a complex or multi-story structure into a sub-frame level. Each sub-frame consists of the beams and columns at one level, together with the columns above and below. The beam-column joints are generally assumed to be fixed. This will calculate the bending moments, shear forces and deflections along the beam. In MiLA Structure, the sub-frame analysis runs by default.

Figure 1: Sub-frame analysis in MiLA Structure

In sub-frame analysis, moments are transferred at beam-column joints.

Continuous Beam Analysis #

Similarly, continuous beam analysis involves the calculation of the bending moments, shear forces and deflections along the length of the beam. At the beam – column joints, beams are generally assumed to be free to rotate. In MiLA Structure, users may opt to run the continuous beam analysis by selecting on the Continuous Beam Analysis button before running the analysis.

Figure 2: Continuous Beam Analysis in MiLA Structure