

ARCHES 59 



The position of wheel loads producing the maximum 

 moment is found by trial. 



Moment Influence Diagram for Two-hinged Arch with Solid 

 Web. For the solid arch the influence diagram is quite 

 simple as it is made up of the combination of the base 

 diagram and the diagram for H, corresponding to unit loads, 

 which is a smooth curve. The moment influence diagram 

 is shown by the shaded area in Fig. 38a. For any other 

 center of moments than the one indicated it is necessary 

 to change only the lines CB and DA. 



Vertical Shear for Two-hinged Arch with Solid Web. The 

 influence diagram for vertical shear is the same as explained 

 for simple trusses on two supports by making the length 

 of the cut stringer zero so that E and F of the base diagram 

 lie in the same vertical line. This diagram is shown in 

 Fig. 386. 



