Page 218 - สะพานเครื่องหนุนมั่น

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2.4 Axial Compression
2.4.1 Stiffeners of plate girders : 27,000 psi

2.4.2 Columns for L/r ratios not greater than 120 :

2
f = 21,300 - 3/8 ( L )
r

L = Unsupported length in inches.
r = Least radius of gyration in inches

2.4.3 Splice material, gross section : 27,000 psi

2.5 Bearing
2.5.1 Rivets and turned bolts : 45,000 psi

2.5.2 Milled stiffeners : 27,000 psi

2.6 Welded constructions :
The allowable unit stress for all welds except fillet welds will be the same as that of the

base metal.

2.7 Bearing on masonry :
2.7.1 Granite : 1,200 psi

2.7.2 Sandstone and limestone : 600 psi

2.7.3 Concrete : 800 psi

2.7.4 Hard brick in cement mortar : 350 psi

2.8 Concrete construction.
2.8.1 28 -day strength : f' = 3,000 psi
c
2.8.2 Compression : f = 0.45 f' = 1,350 psi
c
c
2.8.3 Reinforcing Steel : fs = 24,000 psi

2.8.4 Bearing ( Steel in concrete ) f = 800 psi
B
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