336 



FORM WORK 



in this type of construction to make the forms for the slabs 

 of |-in. plain boards, frequently using tongued-and-grooved 

 material. 



FIG. 6 



Collapsible Forms. Several attempts have been made to 

 arrange the forms for a reinforced-concrete floor system so 

 that they will partly collapse and thus be easy to take down 

 or away from the concrete as soon as it has properly set. 

 One type of collapsible form is shown in Fig. 5. In this 

 construction, the side forms for the beams are embodied with 

 the slab centering by the construction of a collapsible box, 



which furnishes a 

 form that is the 

 exact shape of the 

 space between two 

 adjacent beams. 

 These boxes are 

 arranged with a 

 hinge c, and when 

 in place they rest 

 upon cap pieces d. 

 In order to take 

 down the forms, 

 the struts are re- 

 p IG 7 moved, and the 



form is allowed to 



double up on the hinges c and thus release itself from the 

 concrete. After the collapsible centering has been removed, 



