394 



Report S.A.A. Advancement of Science. 



square root of the moment M. For the law of power can then also 

 be substituted the proportion between the elongations and the strains, 

 so that we obtain the distribution of the strain as shown in Fig. 



» 2 



Figure III. 



No. 3. Through the equality of the tensile and compressive force, 

 and on condition that the elongations of the concrete and iron are 

 proportionate to the distance from the neutral axis, we obtain for 

 the calculation of the distance x of the neutral axis, the quadratic 

 equation : — 



x^ + 2fe X a X X = 2fe x a x h, 

 wherein 



Ee 



a = 



Ec 



10. 



Having obtained x, it is possible if Z represents tension, and D 

 compression, to find that 



M 



Z=D 



h-^ 



and 



de 



D 

 fe 



dc = 



2X D 



X 



respectively. 



This method thus enables the experimenter to determine in a 

 simple manner the strain of a given construction, but formulae can 

 also be given for calculating the dimensions of a construction to be 

 erected, namely : — 



, de + axdc 

 h = X 



do 

 fe: 



/ 



6M 



a(3 X de + 2 X a X dc) 

 h X dc^ X a 



2 X dc (de + a x dc) 



