with Lateral and Non-Axial Loads. 



207 



for the lateral loads only, it is necessary to draw the primary 

 deflexion diagram pQr. A base-line at is then taken such 

 that the area intercepted by the deflexion curve of the beam 

 which lies above the base-line is equal to the area of that 

 lying below the base-line. This diagram will then represent 

 to scale the bending moments induced in the beam by the 

 endlong load, supposing the beam to bend exactly to this 

 shape. Should further accuracy be desired the secondary 

 deflexion diagram may now be drawn and treated in a 

 similar manner, that is, a base-line selected which shall make 

 its total area equal to zero. 



When a beam is under an irregular lateral load and is at 

 the same time built in horizontally at the ends, an additional 

 condition must be fulfilled by all the bending moment 

 diagrams involved, whether due to the lateral system only 

 or to the endlong loadings. This condition, which arises 



AL. 



Bejretmg mo/ne/7? r/Zavra/Ti /#/• 

 loads W f W ? W 3 on?y. 



Pr/mary a'\f/ectw/z cxrye. 



CofG of 

 Def/ect/o/i I 





% 



from the fact that each support lies upon the tangent to the 

 beam at the other abutment, states that the moment of the 

 bending moment diagram about either end must be equal to 

 zero. If abc, fig. 3, represents the curve of bending moments 

 due to the lateral load acting upon the beam as a free-ended 



