How do you determine the collapse load of a continuous beam using plastic analysis?

To find collapse load: (1) Identify all possible collapse mechanisms by placing plastic hinges at locations of maximum moment, (2) For each mechanism, apply virtual work equation: external work = internal work, giving Sum(P*delta) = Sum(Mp*theta), (3) Solve for collapse load for each mechanism, (4) The actual collapse load is the minimum value. For a two-span continuous beam with uniform load, hinges form at interior support and within spans. The mechanism method or kinematic approach provides upper bound solutions.