A uniform beamoflength L, flexural rigidity EI and cross-sectional plastic moment Mp is built-in at both ends and carries a uniformly distributed load, w, which is gradually increased from zero until the beam collapses. Define the behaviour of the beam as it approaches collapse by deriving expressions for the deflection at the mid-point of the beam as a function of the distributed load, w, and the beam properties. Sketch the typical form of the resultant load-deflection curve.