BLAR12054 Structural Design Processes

1.0 Moment Distribution Method

Using the Moment Distribution Method, the bending moments will be calculated for the frame shown in Figure 1. The findings will be checked against the formulae from (insert steel manual reference). Once the findings have been checked, a bending moment diagram will be provided.

Figure 1According to .. (), the process of carrying out the moment distribution method, consists of the following:1. Calculate the fixed-end moments (FEM)2. Find the relative stiffness3. Calculate the distribution factors (DF)4. Formulate a distribution table5. Sketch a bending moment diagramThe findings have been calculated using the following formulas (insert reference), with the numbers updated accordingly:Fixed-end moments for built-in beams

Relative stiffness

1.1Calculating fixed-end moments *The FEM at joint AB &DC are zero as they carry no load.

1.2Calculating the relative stiffness

1.3Calculating the distribution factors

Therefore, the distribution factors are summarised as follows: AB & DC = 0 (joints are locked) BA & BC = 0.714 & 0.286 respectively CB & CD = 0.714 & 0.286 respectively1.4Distribution table

1.5Checking against the formula in reading 2.1

1.6Bending Moment Diagram

Bending moment at mid-span for an unrestrained beam: