# Influence Lines for Beams Continuous Over Three Spans

*1. Introduction.
VARIOUS methods of solving continuous beam problems have been published, but all those known to the authors involve the drawing of complete bending moment diagrams for each position of the load. From these diagrams the influence quantities can be obtained by measurement and calculation. In the following paper, a method of drawing the influence lines directly is presented. The case of a three-span beam has been taken, as this is
very common in practice, but the method can easily be extended to more complicated cases. Some of the expressions appear a little cumbersome when symbols are used for the span lengths, but for actual numerical cases they are very simple, as will be seen by the example in Section (3).
R.J. Cornish
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Author(s): Cornish, R J;Jones, Eric

Keywords: beams;continuous structural members;analysis;influence line methods;worked examples