18 STANDARD SPECIFICATIONS 



(d) Shear on: turned bolts and field rivets, when 



hand driven 9,000 Ibs. 



Field rivets, when power driven 1 1,000 ' ' 



Shop driven rivets and pins 12,000 " 



Plate girder webs, gross section 10,000 ' ' 



(e) Bearing on: turned bolts and field rivets, when 



hand driven 18,000 ' ' 



Field rivets, when power driven 22,000 ' ' 



Shop-driven rivets and pins 24,000 ' ' 



66. Pressure on Foundations. The pressure on masonry 

 foundations shall not exceed the following values in pounds per 

 square inch: 



Portland cement concrete 1:2: 4 and first-class sandstone 



or limestone masonry, including impact 400 Ibs. 



Portland cement concrete 1:2:0 (granitoid) and first -da-- 

 granite masonry, including impact 600 ' ' 



67. Pressure on Soils. For allowable pressures see Par. 20. 



68. Timber. For allowable stresses see Part VII. 



69. Expansion Rollers. 



Allowable pressure per lin.in GOOd 



where d = diameter of roller in inches. 



70. Cast Steel. The maximum stresses shall not exceed, in 

 Ibs, per square inch, for, 



Tension 16,000 Ibs. 



Compression (on blocks) 16,000 " 



Shear 10,000 ' ' 



71. Combined Stresses. All members in a structure exposed 

 to bending stresses from a transverse loading, due either to the 

 weight of the member itself, or to the weight of the floor system 

 when it rests directly on one of the chords, shall be designed for 

 the maximum combination of such stresses with the axial stresses, 

 including impact for each kind of loading, using an extreme 

 fiber stress of 16,000 Ibs. per sq.in. 



Where the bending stresses are due only to the weight of the 



