78 STANDARD SPECIFICATIONS 



335. Removal of Forms: 



(a) The t'.me for removal of forms and shores, being an 

 extremely important consideration, shall be determined 

 in each case by the engineer after inspection. As a 

 guide the following important determinants are men- 

 tioned; size of structure and general dimensions of parts; 

 methods of mixing and proportions of mixture ; whether 

 slow or quick-setting cements are used; atmospheric 

 conditions; importance of live loading and its ratio 

 to the dead load; length of period between the removal 

 of forms and shores and the time when the maximum 

 loading may be attained, etc. But in any case the 

 supporting shores shall be left in place until their re- 

 moval is permitted by the engineer. 



\b) The minimum time for the removal of Forms (not the 

 supporting shores shall be as follows: 



For Bottom of Slabs 4 days, for spans of 4 ft. or less, plus 

 1 day extra for each additional foot of span. 



For Sides and Beams and Girders 7 days. 



For Columns 4 days. 



For Bridge Arches 28 days. 



f c) The minimum time for the removal of Shores shall be as 

 follows : 



For Bottoms of Beams and Girders 21 days, for spans of 

 10 ft. or less, plus one-half (i) day for each additional 

 foot of span. 



The original shores must in no case be taken down, replaced 

 or disturbed, until permitted by the Engineer. 



(d) When frosty weather occurs during the above periods an 



extension of time shall be made equal to its duration. 



(e) During the setting and before the removal of forms no 



extraneous loading shall be placed upon the concrete. 

 (/) The forms shall be removed with care so as not to deface 

 the structure or to disturb the remaining supports. 



LOADS 



336. Dead Load. The dead load consists of: 

 (a) The weight of the reinforced concrete, which shall be 

 taken at 150 Ibs. per cubic foot. 



