GRAIN- PRESSURES IKT STORAGE BINS. 



Table 2. — Steel factors for horizontal reinforcing in cylindrical concrete tanks. 

 [Areas of steel per foot in height per diameter squared.] 







a 









a 





H 





W 





H 





2)2 





D 









J) 









/s= 16000 



/a= 18000 



/s=20000 





/■3= 16000 



/s=lS000 



/b= 20000 



0.1 



0.000089 



0.000079 



0.000072 



2.3 



0. 000843 



0.000749 



0.000675 



.2 



170 



151 



136 



2.4 



853 



758 



682 



.3 



243 



216 



194 



2.5 



860 



765 



688 



.4 



309 



274 



247 



2.6 



868 



771 



694 



.5 



369 



328 



295 



2.7 



874 



777 



700 



.6 



423 



376 



338 



2.8 



881 



783 



705 



.7 



472 



419 



378 



2.9 



8,86 



787 



709 



.8 



516 



459 



413 



3.0 



.000891 



. 000792 



. 000713 



.9 



5.56 



494 



445 



3 1 



895 



795 



716 



1.0 



. 000593 



.000527 



.000474 



3 2 



899 



799 



719 



1.1 



625 



556 



500 



3.3 



903 



802 



722 



1.2 



655 



582 



524 



3.4 



906 



805 



725 



1.3 



682 



606 



546 



3.5 



909 



808 



727 



1.4 



706 



628 



565 



3.6 



912 



810 



729 



1..5 



728 



647 



583 



3.7 



914 



813 



731 



1.6 



748 



665 



599 



3.8 



917 



815 



733 



1.7 



760 



675 



608 



3.9 



918 



816 



735 



1.8 



783 



695 



626 



4.0 



. 000920 



.000818 



. 000736 



1.9 



797 



708 



638 



5.0 



931 



827 



745 



2.0 



.000811 



.000720 



.000649 



6.0 



935 



831 



748 



2.1 



823 



731 



658 



7.0 



936 



832 



749 



2.2 



833 



741 



667 



10.0 



. 000937 



. 000833 



. 000750 



[For use of this table, see Example 2, page 11. 



HORIZONTAL REINFORCING FOR STRAIGHT WALLS OF CONCRETE 



BINS. 



In all bins other than cylmdrical tanks the walls are designed as 

 slabs supporting at any given level a uniform load equal to the 

 lateral grain pressure at that point. 



Tables 3a, 3&, and 3c, for different allowable stresses in steel and 

 concrete, give the maximum resisting moments and the steel areas 

 required for different effective thicknesses of walls. Also, for dif- 

 ferent conditions of continuity, constants are listed for determining 

 the heights at which the size or spacing of the bars may be changed. 



In the following, the standard nomenclature for reinforced con- 

 crete is used also : Let — 



i== lateral pressure of the grain in pounds per square foot. 



Z=span of waU in feet. 



t = thickness of waU in inches. 



e = thickness of concrete outside of steel in inches. 



(^ = ^ — e = effective depth to steel in inches. 



a = area of steel per foot in height in square inches. 



J/= bending moment or resisting moment in inch pounds. 



m = coefficient of continuity for figuring bending moment. 



LxPxl2 



= 8 for simple spans M= 



= 10 for end spans — partial continuity Jf= 



LxPxl2 



10 



= 12 for intermediate spans — full continuity M-- 



LxPxl2 

 12 



