ALGEBRAIC CALCULATION OF REACTIONS I Z I 



is probably easier to understand. The algebraic solution will be given 

 first. 



Algebraic Calculation of Reactions. In Table VII the values 



of the unit stress, P, in each member due to the external loads are given 

 p j^ 



in column 5 ; values of are given in column 6 ; values of the stress, 

 .ci 



U, in each member due to a unit horizontal thrust are given in column 



P U L 



8 ; and values of are given in column 9. The algebraic sum of 



the quantities in column 9 gives the total deformation, A = .956 

 inches at the point where the unit horizontal thrust was applied meas- 

 ured parallel to the line of action of the thrust. 



TABLE VII. 



Simple Truss with Vertical Loads 



In Table VIII similar values are given for the arch as a truss 

 with an assumed horizontal reaction of H 1 = 20000 Ihs. The algebraic 

 sum of the quantities in column 9 gives the total deformation, A' = 

 . 574 inches at the point where the horizontal thrust was applied. 



