TIMBER FLOORS. 



35 



crete as shown in (c) and (d), of steel filled with concrete as shown in (), (/), (g), (A), or of 

 concrete reinforced with Buckeye flooring as shown in (*') or Multiplex flooring as shown in (j). 



Timber Floors. The Yellow Pine Manufacturers Association has calculated the safe 

 span of yellow pine when used for mill floors with fiber stresses of 1,200 to 1, 800 Ib. per sq. in. 

 for live loads of 100 to 300 Ib. per sq. ft. in addition to the weight of the floor, Table V. In the 

 line in. irked " Deflection " is given the span which has a maximum deflection of one thirtieth of 

 an inch per foot of span for the various live loads. The modulus of elasticity of timber was taken 

 as 1 ,684,800 Ib. per sq. in. The table may be used for any kind of timber by using the proper 

 working stress. The maximum spans for fiber stresses less than 1,200 Ib. per sq. in. may be found 

 as follows: Required the maximum safe span for a timber floor 2\ in. thick for a fiber stress of 

 800 Ib. per sq. in. and a live load of 150 Ib. per sq. ft. The span is approximately the same as for 

 a fiber stress of 1,200 Ib. per sq. in. and a live load of 225 Ib. per sq. ft., = 6 ft. II in.; or for a 

 fiber stress of 1,600 Ib. per sq. in. and a live load of 300 Ib. per sq. ft., = 6 ft. n in. 



TABLE V. 



ALLOWABLE SPAN FOR TIMBER. FLOORS. 

 YELLOW PINE MANUFACTURERS ASSOCIATION. 



Waterproofing. For methods of waterproofing floors, walls, etc., see methods of waterproofing 

 bridge floors in Chapter IV. 



